WorldWideScience

Sample records for binary orbit physical

  1. Capella (alpha Aurigae) revisited: New binary orbit, physical properties, and evolutionary state

    CERN Document Server

    Torres, Guillermo; Pavlovski, Kresimir; Dotter, Aaron

    2015-01-01

    Knowledge of the chemical composition and absolute masses of Capella are key to understanding the evolutionary state of this benchmark binary system comprising two giant stars. Previous efforts, including our own 2009 study, have largely failed to reach an acceptable agreement between the observations and current stellar evolution models, preventing us from assessing the status of the primary. Here we report a revision of the physical properties of the components incorporating recently published high-precision radial velocity measurements, and a new detailed chemical analysis providing abundances for more than 20 elements in both stars. We obtain highly precise (to about 0.3%) masses of 2.5687 +/- 0.0074 and 2.4828 +/- 0.0067 solar masses, radii of 11.98 +/- 0.57 and 8.83 +/- 0.33 solar radii, effective temperatures of 4970 +/- 50 K and 5730 +/- 60 K, and independently measured luminosities based on the orbital parallax (78.7 +/- 4.2 and 72.7 +/- 3.6 solar luminosities). We find an excellent match to stellar ...

  2. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- IX. Spotted pairs with red giants

    OpenAIRE

    Ratajczak, M.; Hełminiak, K. G.; Konacki, M.; Smith, A.M.S.; Kozłowski, S. K.; Espinoza, N.; Jordán, A.; Brahm, R.; Hempel, M; Anderson, D R; Hellier, C.

    2016-01-01

    We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V-, and I-band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of t...

  3. The orbital and physical parameters of the OW Gemiorum eclipsing binary

    CERN Document Server

    Gałan, C; Tomov, T; Kolev, D; Graczyk, D; Majcher, A; Janowski, J Ł; Cika?a, M

    2008-01-01

    We present our multicolour photometric data of the primary and secondary eclipses of OW Gem which took place in 1995, 2002 and 2006 as well as the new radial velocity data collected since 1993 by R.F. Griffin and A. Duquennoy. The Wilson - Devinney code was used for simultaneous solution of both photometric and spectroscopic data. A complete set of orbital and physical parameters of the components was obtained. The pair of values, eccentricity e=0.5286 and argument of periastron omega=140.73 degree give better compatibility of the moment of the secondary minimum with the observations relative to previous estimates.

  4. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- IX. Spotted pairs with red giants

    CERN Document Server

    Ratajczak, M; Konacki, M; Smith, A M S; Kozłowski, S K; Espinoza, N; Jordán, A; Brahm, R; Hempel, M; Anderson, D R; Hellier, C

    2016-01-01

    We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V-, and I-band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of the investigated systems (ASAS J184949-1518.7, BQ Aqr, and V1207 Cen) show the differential evolutionary phase of their components consisting of a main sequence star or a subgiant and a red giant, and thus constitute very informative objects in terms of testing stellar evolution models. Additionally, the systems show significant chromospheric activity of both components. They can be also classified as classical RS CVn-type stars. Besides the standard analysis of radial velocities and photometry, we applied spectral disenta...

  5. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - IX. Spotted pairs with red giants

    Science.gov (United States)

    Ratajczak, M.; Hełminiak, K. G.; Konacki, M.; Smith, A. M. S.; Kozłowski, S. K.; Espinoza, N.; Jordán, A.; Brahm, R.; Hempel, M.; Anderson, D. R.; Hellier, C.

    2016-09-01

    We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V-, and I-band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of the investigated systems (ASAS J184949-1518.7, BQ Aqr, and V1207 Cen) show the differential evolutionary phase of their components consisting of a main-sequence star or a subgiant and a red giant, and thus constitute very informative objects in terms of testing stellar evolution models. Additionally, the systems show significant chromospheric activity of both components. They can be also classified as classical RS CVn-type stars. Besides the standard analysis of radial velocities and photometry, we applied spectral disentangling to obtain separate spectra for both components of each analysed system which allowed for a more detailed spectroscopic study. We also compared the properties of red giant stars in binaries that show spots, with those that do not, and found that the activity phenomenon is substantially suppressed for stars with Rossby number higher than ˜1 and radii larger than ˜20 R⊙.

  6. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - IV. A 0.61 + 0.45 M_sun binary in a multiple system

    CERN Document Server

    Hełminiak, K G; Rozyczka, M; Kaluzny, J; Ratajczak, M; Borkowski, J; Sybilski, P; Muterspaugh, M W; Reichart, D E; Ivarsen, K M; Haislip, J B; Crain, J A; Foster, A C; Nysewander, M C; LaCluyze, A P

    2012-01-01

    We present the orbital and physical parameters of a newly discovered low-mass detached eclipsing binary from the All-Sky Automated Survey (ASAS) database: ASAS J011328-3821.1 A - a member of a visual binary system with the secondary component separated by about 1.4 seconds of arc. The radial velocities were calculated from the high-resolution spectra obtained with the 1.9-m Radcliffe/GIRAFFE, 3.9-m AAT/UCLES and 3.0-m Shane/HamSpec telescopes/spectrographs on the basis of the TODCOR technique and positions of H_alpha emission lines. For the analysis we used V and I band photometry obtained with the 1.0-m Elizabeth and robotic 0.41-m PROMPT telescopes, supplemented with the publicly available ASAS light curve of the system. We found that ASAS J011328-3821.1 A is composed of two late-type dwarfs having masses of M_1 = 0.612 +/- 0.030 M_sun, M_2 = 0.445 +/- 0.019 M_sun and radii of R_1 = 0.596 +/- 0.020 R_sun, R_2 = 0.445 +/- 0.024 R_sun, both show a substantial level of activity, which manifests in strong H_alp...

  7. Orbital and Physical Parameters of Visual Binary: WDS 17190-3459 ({\\alpha} 2000 = 17h 18m 56s and {\\delta} 2000 = - 34o 59' 22")

    CERN Document Server

    Nugraha, Rukman

    2010-01-01

    Since the Bosscha Observatory was established in 1923 researches on visual binary stars played an important role in astronomical studies in Indonesia. The visual binary of WDS 17190-3459 = MLO 4AB = HD156384 = HIP84709 was extensively observed at our observatory and other observatories. This system has already passed periastron three times since observed in the end of year 1876. The observation data is more than enough to construct an orbit. By using Thiele-Innes method we computed the orbit, and physical parameters are determined by using mass-luminosity relation. The result is presented in the table. Orbital Parameters: e = 0.578, P = 42.3 years, T = 1974.9, i = 132 o.7,{\\omega} = 247o.5, {\\Omega} = 318o.1, a = 1".713, mu = 8 o.51/years Physical Parameters:p = 0".134, Mbol1 = 6.7, Mbol2 = 7.4, M1 = 0.6 Mo, M2 = 0.5 Mo, q = 0.863. At time being there are several new methods for determining the orbit; for example the method of Gauss done by S\\"oderhjelm (1999) for calculating the orbit of the same stars WDS 1...

  8. The orbital elements and physical properties of the eclipsing binary BD+36 3317, a probable member of $\\delta$ Lyr cluster

    CERN Document Server

    Kıran, E; Değirmenci, Ö L; Wolf, M; Nemravová, J; Šlechta, M; Koubský, P

    2016-01-01

    Context. The fact that eclipsing binaries belong to a stellar group is useful, because the former can be used to estimate distance and additional properties of the latter, and vice versa. Aims. Our goal is to analyse new spectroscopic observations of BD$+36^\\circ3317$ along with the photometric observations from the literature and, for the first time, to derive all basic physical properties of this binary. We aim to find out whether the binary is indeed a member of the $\\delta$ Lyr open cluster. Methods. The spectra were reduced using the IRAF program and the radial velocities were measured with the program SPEFO. The line spectra of both components were disentangled with the program KOREL and compared to a grid of synthetic spectra. The final combined radial-velocity and photometric solution was obtained with the program PHOEBE. Results. We obtained the following physical elements of BD$+36^\\circ3317$: $M_1 = 2.24\\pm0.07 M_{\\odot}$, $M_2 = 1.52\\pm0.03 M_{\\odot}$, $R_1 = 1.76\\pm0.01 R_{\\odot}$, $R_2 = 1.46\\pm...

  9. Orbital and physical parameters of eclipsing binaries from the All-Sky Automated Survey catalogue - VI. AK Fornacis - a rare, bright K-type eclipsing binary

    CERN Document Server

    Hełminiak, K G; Ratajczak, M; Espinoza, N; Jordán, A; Konacki, M; Rabus, M

    2014-01-01

    We present the results of the combined photometric and spectroscopic analysis of a bright (V=9.14), nearby (d=31 pc), late-type detached eclipsing binary AK Fornacis. This P=3.981 d system has not been previously recognised as a double-lined spectroscopic binary, and this is the first full physical model of this unique target. With the FEROS, CORALIE and HARPS spectrographs we collected a number of high-resolution spectra in order to calculate radial velocities of both components of the binary. Measurements were done with our own disentangling procedure and the TODCOR technique, and were later combined with the photometry from the ASAS and SuperWASP archives. We also performed an atmospheric analysis of the component spectra with the Spectroscopy Made Easy (SME) package. Our analysis shows that AK For consists of two active, cool dwarfs having masses of $M_1=0.6958 \\pm 0.0010$ and $M_2=0.6355 \\pm 0.0007$ M$_\\odot$ and radii of $R_1=0.687 \\pm 0.020$ and $R_2=0.609 \\pm 0.016$ R$_\\odot$, slightly less metal abun...

  10. Orbital and physical parameters, and the distance of the eclipsing binary system OGLE-LMC-ECL-25658 in the Large Magellanic Cloud

    CERN Document Server

    Elgueta, S S; Gieren, W; Pietrzynski, G; Thompson, I B; Konorski, P; Pilecki, B; Villanova, S; Udalski, A; Soszynski, I; Suchomska, K; Karczmarek, P; Gorski, M; Wielgorski, P

    2016-01-01

    We present an analysis of a new detached eclipsing binary, OGLE-LMC-ECL-25658, in the Large Magellanic Cloud. The system consists of two late G-type giant stars on an eccentric orbit and orbital period of ~200 days. The system shows total eclipses and the components have similar temperatures, making it ideal for a precise distance determination. Using multi-color photometric and high resolution spectroscopic data, we have performed an analysis of light and radial velocity curves simultaneously using the Wilson Devinney code. We derived orbital and physical parameters of the binary with a high precision of < 1 %. The masses and surface metallicities of the components are virtually the same and equal to 2.23 +/- 0.02 M_sun and [Fe/H] = -0.63 +/- 0.10 dex. However their radii and rates of rotation show a distinct trace of differential stellar evolution. The distance to the system was calculated using an infrared calibration between V-band surface brightness and (V-K) color, leading to a distance modulus of (m...

  11. PHOEBE: PHysics Of Eclipsing BinariEs

    Science.gov (United States)

    Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick

    2011-06-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability.

  12. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - VIII. The totally-eclipsing double-giant system HD 187669

    CERN Document Server

    Hełminiak, K G; Konacki, M; Pilecki, B; Ratajczak, M; Pietrzyński, G; Sybilski, P; Villanova, S; Gieren, W; Pojmański, G; Konorski, P; Suchomska, K; Reichart, D E; Ivarsen, K M; B., J; Haislip,; LaCluyze, A P

    2014-01-01

    We present the first full orbital and physical analysis of HD 187669, recognized by the All-Sky Automated Survey (ASAS) as the eclipsing binary ASAS J195222-3233.7. We combined multi-band photometry from the ASAS and SuperWASP public archives and 0.41-m PROMPT robotic telescopes with our high-precision radial velocities from the HARPS spectrograph. Two different approaches were used for the analysis: 1) fitting to all data simultaneously with the WD code, and 2) analysing each light curve (with JKTEBOP) and RVs separately and combining the partial results at the end. This system also shows a total primary (deeper) eclipse, lasting for about 6 days. A spectrum obtained during this eclipse was used to perform atmospheric analysis with the MOOG and SME codes in order to constrain physical parameters of the secondary. We found that ASAS J195222-3233.7 is a double-lined spectroscopic binary composed of two evolved, late-type giants, with masses of $M_1 = 1.504\\pm0.004$ and $M_2=1.505\\pm0.004$ M$_\\odot$, and radii ...

  13. The Orbital and Physical Parameters, and the Distance of the Eclipsing Binary System OGLE-LMC-ECL-25658 in the Large Magellanic Cloud

    Science.gov (United States)

    Elgueta, S. S.; Graczyk, D.; Gieren, W.; Pietrzyński, G.; Thompson, I. B.; Konorski, P.; Pilecki, B.; Villanova, S.; Udalski, A.; Soszyński, I.; Suchomska, K.; Karczmarek, P.; Górski, M.; Wielgórski, P.

    2016-08-01

    We present an analysis of a new detached eclipsing binary, OGLE-LMC-ECL-25658, in the Large Magellanic Cloud (LMC). The system consists of two late G-type giant stars on an eccentric orbit with an orbital period of ˜200 days. The system shows total eclipses and the components have similar temperatures, making it ideal for a precise distance determination. Using multi-color photometric and high resolution spectroscopic data, we have performed an analysis of light and radial velocity curves simultaneously using the Wilson–Devinney code. We derived orbital and physical parameters of the binary with a high precision of \\lt 1%. The masses and surface metallicities of the components are virtually the same and equal to 2.23+/- 0.02 {M}ȯ and [{Fe}/{{H}}]\\=\\-0.63+/- 0.10 dex. However, their radii and rates of rotation show a distinct trace of differential stellar evolution. The distance to the system was calculated using an infrared calibration between V-band surface brightness and (V–K) color, leading to a distance modulus of (m-M)\\=\\18.452+/- 0.023 (statistical) ± 0.046 (systematic). Because OGLE-LMC-ECL-25658 is located relatively far from the LMC barycenter, we applied a geometrical correction for its position in the LMC disk using the van der Marel et al. model of the LMC. The resulting barycenter distance to the galaxy is {d}{{LMC}}\\=\\50.30+/- 0.53 (stat.) kpc, and is in perfect agreement with the earlier result of Pietrzyński et al.

  14. Orbital dynamics of binary boson star systems

    International Nuclear Information System (INIS)

    We extend our previous studies of head-on collisions of boson stars by considering orbiting binary boson stars. We concentrate on equal-mass binaries and study the dynamical behavior of boson/boson and boson/antiboson pairs. We examine the gravitational wave output of these binaries and compare with other compact binaries. Such a comparison lets us probe the apparent simplicity observed in gravitational waves produced by black hole binary systems. In our system of interest however, there is an additional internal freedom which plays a significant role in the system's dynamics, namely, the phase of each star. Our evolutions show rather simple behavior at early times, but large differences occur at late times for the various initial configurations

  15. Binary black hole circular orbits computed with COCAL

    CERN Document Server

    Tsokaros, Antonios

    2012-01-01

    In this work we present our first results of binary black hole circular orbits using {\\sc cocal}, the Compact Object CALculator. Using the 3+1 decomposition five equations are being solved under the assumptions of conformal flatness and maximal slicing. Excision is used and the appropriate apparent horizon boundary conditions are applied. The orbital velocity is determined by imposing a Schwarzschild behaviour at infinity. A sequence of equal mass black holes is obtained and its main physical characteristics are calculated.

  16. Early-type Eclipsing Binaries at Intermediate Orbital Periods

    CERN Document Server

    Moe, Maxwell

    2015-01-01

    We analyze 221 eclipsing binaries (EBs) in the Large Magellanic Cloud with B-type main-sequence (MS) primaries ($M_1$ $\\approx$ 4 - 14 M$_{\\odot}$) and orbital periods $P$ = 20 - 50 days that were photometrically monitored by the Optical Gravitational Lensing Experiment. We utilize our three-stage automated pipeline to (1) classify all 221 EBs, (2) fit physical models to the light curves of 130 detached well-defined EBs from which unique parameters can be determined, and (3) recover the intrinsic binary statistics by correcting for selection effects. We uncover two statistically significant trends with age. First, younger EBs tend to reside in dustier environments with larger photometric extinctions, an empirical relation that can be implemented when modeling stellar populations. Second, younger EBs generally have large eccentricities. This demonstrates that massive binaries at moderate orbital periods are born with a Maxwellian "thermal" orbital velocity distribution, which indicates they formed via dynamica...

  17. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- I. A sample of systems with components' masses between 1 and 2 M$_\\odot$

    CERN Document Server

    Hełminiak, K G; Ratajczak, M; Muterspaugh, M

    2009-01-01

    We derive the absolute physical and orbital parameters for a sample of 18 detached eclipsing binaries from the \\emph{All Sky Automated Survey} (ASAS) database based on the available photometry and our own radial velocity measurements. The radial velocities (RVs) are computed using spectra we collected with the 3.9-m Anglo-Australian Telescope and its \\emph{University College London Echelle Spectrograph} and the 1.9-m SAAO Radcliffe telescope and its \\emph{Grating Instrument for Radiation Analysis with a Fibre Fed Echelle}. In order to obtain as precise RVs as possible, most of the systems were observed with an iodine cell available at the AAT/UCLES and/or analyzed using the two-dimensional cross-correlation technique (TODCOR). The RVs were measured with TODCOR using synthetic template spectra as references. However, for two objects we used our own approach to the tomographic disentangling of the binary spectra to provide observed template spectra for the RV measurements and to improve the RV precision even mo...

  18. Orbits of Ten Visual Binary Stars

    Institute of Scientific and Technical Information of China (English)

    B.Novakovi(c)

    2007-01-01

    We present the orbits of ten visual binary stars:WDS 01015+6922.WDS 01424-0645,WDS 01461+6349,WDS 04374-0951,WDS 04478+5318,WDS 05255-0033,WDS 05491+6248,WDS 06404+4058,WDS 07479-1212,and WDS 18384+0850.We have also determined their masses,dynamical parallaxes and ephemerides.

  19. Spectroscopic Orbits for Kepler FOV Eclipsing Binaries

    Science.gov (United States)

    Matson, Rachel A.; Gies, Douglas R.; Williams, Stephen J.; Guo, Zhao

    2013-02-01

    We are currently involved in a four year program of precise eclipsing binary photometry with the NASA Kepler Observatory. Our goal is to search for variations in minimum light timing for intermediate mass eclipsing binaries. Such periodic variations will reveal the reflex motion caused by any distant, low mass object that orbits the close binary. it Kepler's unprecedented accuracy and continuous observations provide a unique opportunity to detect the low mass companions that are predicted to result from the angular momentum of the natal cloud. The goal of this proposal is to obtain blue spectra of short period (0.9-6d) eclipsing binaries, derive radial velocities, and produce a double-lined spectroscopic orbit (as well as estimates of the stellar effective temperatures, gravities, and metallicities). Combined with the it Kepler light curve, we will determine very accurate masses and radii for the members of the close binary, which will yield the mass-inclination product M_3 sin i for any companions detected by light travel time or other effects. An extended sample of eclipsing binaries with longer periods (up to 50d) is now being investigated to test whether the presence of a tertiary companion declines with increasing period. We propose to obtain a single spectrum at quadrature for the brightest 48 stars in this expanded sample to characterize the effective temperatures and total mass contained in these systems.

  20. Orbital eccentricities in primordial black holes binaries

    CERN Document Server

    Cholis, Ilias; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on timescales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO a...

  1. Detectability of orbital motion in stellar binary and planetary microlenses

    Science.gov (United States)

    Penny, Matthew T.; Mao, Shude; Kerins, Eamonn

    2011-03-01

    A standard binary microlensing event light curve allows just two parameters of the lensing system to be measured: the mass ratio of the companion to its host and the projected separation of the components in units of the Einstein radius. However, other exotic effects can provide more information about the lensing system. Orbital motion in the lens is one such effect, which, if detected, can be used to constrain the physical properties of the lens. To determine the fraction of binary-lens light curves affected by orbital motion (the detection efficiency), we simulate light curves of orbiting binary star and star-planet (planetary) lenses and simulate the continuous, high-cadence photometric monitoring that will be conducted by the next generation of microlensing surveys that are beginning to enter operation. The effect of orbital motion is measured by fitting simulated light-curve data with standard static binary microlensing models; light curves that are poorly fitted by these models are considered to be detections of orbital motion. We correct for systematic false positive detections by also fitting the light curves of static binary lenses. For a continuous monitoring survey without intensive follow-up of high-magnification events, we find the orbital motion detection efficiency for planetary events with caustic crossings to be 0.061 ± 0.010, consistent with observational results, and 0.0130 ± 0.0055 for events without caustic crossings (smooth events). Similarly, for stellar binaries, the orbital motion detection efficiency is 0.098 ± 0.011 for events with caustic crossings and is 0.048 ± 0.006 for smooth events. These result in combined (caustic-crossing and smooth) orbital motion detection efficiencies of 0.029 ± 0.005 for planetary lenses and 0.070 ± 0.006 for stellar binary lenses. We also investigate how various microlensing parameters affect the orbital motion detectability. We find that the orbital motion detection efficiency increases as the binary

  2. The EBLM Project I-Physical and orbital parameters, including spin-orbit angles, of two low-mass eclipsing binaries on opposite sides of the Brown Dwarf limit

    CERN Document Server

    Triaud, Amaury H M J; Anderson, David R; Cargile, Phill; Cameron, Andrew Collier; Doyle, Amanda P; Faedi, Francesca; Gillon, Michaël; Chew, Yilen Gomez Maqueo; Hellier, Coel; Jehin, Emmanuel; Maxted, Pierre; Naef, Dominique; Pepe, Francesco; Pollacco, Don; Queloz, Didier; Ségransan, Damien; Smalley, Barry; Stassun, Keivan; Udry, Stéphane; West, Richard G

    2012-01-01

    This paper introduces a series of papers aiming to study the dozens of low mass eclipsing binaries (EBLM), with F, G, K primaries, that have been discovered in the course of the WASP survey. Our objects are mostly single-line binaries whose eclipses have been detected by WASP and were initially followed up as potential planetary transit candidates. These have bright primaries, which facilitates spectroscopic observations during transit and allows the study of the spin-orbit distribution of F, G, K+M eclipsing binaries through the Rossiter-McLaughlin effect. Here we report on the spin-orbit angle of WASP-30b, a transiting brown dwarf, and improve its orbital parameters. We also present the mass, radius, spin-orbit angle and orbital parameters of a new eclipsing binary, J1219-39b (1SWAPJ121921.03-395125.6, TYC 7760-484-1), which, with a mass of 95 +/- 2 Mjup, is close to the limit between brown dwarfs and stars. We find that both objects orbit in planes that appear aligned with their primaries' equatorial plane...

  3. The disruption of multiplanet systems through resonance with a binary orbit.

    Science.gov (United States)

    Touma, Jihad R; Sridhar, S

    2015-08-27

    Most exoplanetary systems in binary stars are of S-type, and consist of one or more planets orbiting a primary star with a wide binary stellar companion. Planetary eccentricities and mutual inclinations can be large, perhaps forced gravitationally by the binary companion. Earlier work on single planet systems appealed to the Kozai-Lidov instability wherein a sufficiently inclined binary orbit excites large-amplitude oscillations in the planet's eccentricity and inclination. The instability, however, can be quenched by many agents that induce fast orbital precession, including mutual gravitational forces in a multiplanet system. Here we report that orbital precession, which inhibits Kozai-Lidov cycling in a multiplanet system, can become fast enough to resonate with the orbital motion of a distant binary companion. Resonant binary forcing results in dramatic outcomes ranging from the excitation of large planetary eccentricities and mutual inclinations to total disruption. Processes such as planetary migration can bring an initially non-resonant system into resonance. As it does not require special physical or initial conditions, binary resonant driving is generic and may have altered the architecture of many multiplanet systems. It can also weaken the multiplanet occurrence rate in wide binaries, and affect planet formation in close binaries. PMID:26310763

  4. Physical Structure of Four Symbiotic Binaries

    Science.gov (United States)

    Kenyon, Scott J. (Principal Investigator)

    1997-01-01

    Disk accretion powers many astronomical objects, including pre-main sequence stars, interacting binary systems, and active galactic nuclei. Unfortunately, models developed to explain the behavior of disks and their surroundings - boundary layers, jets, and winds - lack much predictive power, because the physical mechanism driving disk evolution - the viscosity - is not understood. Observations of many types of accreting systems are needed to constrain the basic physics of disks and provide input for improved models. Symbiotic stars are an attractive laboratory for studying physical phenomena associated with disk accretion. These long period binaries (P(sub orb) approx. 2-3 yr) contain an evolved red giant star, a hot companion, and an ionized nebula. The secondary star usually is a white dwarf accreting material from the wind of its red giant companion. A good example of this type of symbiotic is BF Cygni: our analysis shows that disk accretion powers the nuclear burning shell of the hot white dwarf and also manages to eject material perpendicular to the orbital plane (Mikolajewska, Kenyon, and Mikolajewski 1989). The hot components in other symbiotic binaries appear powered by tidal overflow from a very evolved red giant companion. We recently completed a study of CI Cygni and demonstrated that the accreting secondary is a solar-type main sequence star, rather than a white dwarf (Kenyon et aL 1991). This project continued our study of symbiotic binary systems. Our general plan was to combine archival ultraviolet and optical spectrophotometry with high quality optical radial velocity observations to determine the variation of line and continuum sources as functions of orbital phase. We were very successful in generating orbital solutions and phasing UV+optical spectra for five systems: AG Dra, V443 Her, RW Hya, AG Peg, and AX Per. Summaries of our main results for these systems appear below. A second goal of our project was to consider general models for the

  5. First Law of Mechanics for Compact Binaries on Eccentric Orbits

    CERN Document Server

    Tiec, Alexandre Le

    2015-01-01

    Using the canonical Arnowitt-Deser-Misner Hamiltonian formalism, a "first law of mechanics" is established for binary systems of point masses moving along generic stable bound (eccentric) orbits. This relationship is checked to hold within the post-Newtonian approximation to general relativity, up to third (3PN) order. Several applications are discussed, including the use of gravitational self-force results to inform post-Newtonian theory and the effective one-body model for eccentric-orbit compact binaries.

  6. First law of mechanics for compact binaries on eccentric orbits

    Science.gov (United States)

    Le Tiec, Alexandre

    2015-10-01

    Using the canonical Arnowitt-Deser-Misner Hamiltonian formalism, a "first law of mechanics" is established for binary systems of point masses moving along generic stable bound (eccentric) orbits. This relationship is checked to hold within the post-Newtonian approximation to general relativity, up to third order. Several applications are discussed, including the use of gravitational self-force results to inform post-Newtonian theory and the effective one-body model for eccentric-orbit compact binaries.

  7. ALIGNMENT OF SUPERMASSIVE BLACK HOLE BINARY ORBITS AND SPINS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M. Coleman [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 (United States); Krolik, Julian H., E-mail: miller@astro.umd.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2013-09-01

    Recent studies of accretion onto supermassive black hole binaries suggest that much, perhaps most, of the matter eventually accretes onto one hole or the other. If so, then for binaries whose inspiral from {approx}1 pc to {approx}10{sup -3}-10{sup -2} pc is driven by interaction with external gas, both the binary orbital axis and the individual black hole spins can be reoriented by angular momentum exchange with this gas. Here we show that, unless the binary mass ratio is far from unity, the spins of the individual holes align with the binary orbital axis in a time {approx}few-100 times shorter than the binary orbital axis aligns with the angular momentum direction of the incoming circumbinary gas; the spin of the secondary aligns more rapidly than that of the primary by a factor {approx}(m{sub 1}/m{sub 2}){sup 1/2} > 1. Thus the binary acts as a stabilizing agent, so that for gas-driven systems, the black hole spins are highly likely to be aligned (or counteraligned if retrograde accretion is common) with each other and with the binary orbital axis. This alignment can significantly reduce the recoil speed resulting from subsequent black hole merger.

  8. Orbital eccentricities in primordial black holes binaries

    OpenAIRE

    Cholis, Ilias; Kovetz, Ely D.; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B.; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly ecce...

  9. The orbital elements and physical properties of the eclipsing binary BD+36°3317, a probable member of δ Lyrae cluster

    Science.gov (United States)

    Kıran, E.; Harmanec, P.; Değirmenci, Ö. L.; Wolf, M.; Nemravová, J.; Šlechta, M.; Koubský, P.

    2016-03-01

    Context. The fact that eclipsing binaries belong to a stellar group is useful, because the former can be used to estimate distance and additional properties of the latter, and vice versa. Aims: Our goal is to analyse new spectroscopic observations of BD+ 36°3317 along with the photometric observations from the literature and, for the first time, to derive all basic physical properties of this binary. We aim to find out whether the binary is indeed a member of the δ Lyr open cluster. Methods: The spectra were reduced using the IRAF program and the radial velocities were measured with the program SPEFO. The line spectra of both components were disentangled with the program KOREL and compared to a grid of synthetic spectra. The final combined radial-velocity and photometric solution was obtained with the program PHOEBE. Results: We obtained the following physical elements of BD+36°3317: M1 = 2.24 ± 0.07 M⊙, M2 = 1.52 ± 0.03 M⊙, R1 = 1.76 ± 0.01 R⊙, R2 = 1.46 ± 0.01 R⊙, log L1 = 1.52 ± 0.08 L⊙, log L2 = 0.81 ± 0.07 L⊙. We derived the effective temperatures Teff,1 = 10 450 ± 420 K, Teff,2 = 7623 ± 328 K. Both components are located close to zero age main sequence in the Hertzsprung-Russell (HR) diagram and their masses and radii are consistent with the predictions of stellar evolutionary models. Our results imply the average distance to the system d̅ = 330 ± 29 pc. We re-investigated the membership of BD+ 36°3317 in the δ Lyr cluster and confirmed it. The distance to BD+ 36°3317, given above, therefore represents an accurate estimate of the true distance for δ Lyr cluster. Conclusions: The reality of the δ Lyr cluster and the cluster membership of BD+ 36°3317 have been reinforced.

  10. Bayesian analysis of exoplanet and binary orbits

    CERN Document Server

    Schulze-Hartung, Tim; Henning, Thomas

    2012-01-01

    We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A.

  11. Resolved astrometric orbits of ten O-type binaries

    CERN Document Server

    Bouquin, J -B Le; Gosset, E; De Becker, M; Duvert, G; Absil, O; Anthonioz, F; Berger, J -P; Ertel, S; Grellmann, R; Guieu, S; Kervella, P; Rabus, M; Willson, M

    2016-01-01

    Our long term aim is to derive model-independent stellar masses and distances for long period massive binaries by combining apparent astrometric orbit with double-lined radial velocity amplitudes (SB2). We follow-up ten O+O binaries with AMBER, PIONIER and GRAVITY at the VLTI. Here, we report about 130 astrometric observations over the last 7 years. We combine this dataset with distance estimates to compute the total mass of the systems. We also compute preliminary individual component masses for the five systems with available SB2 radial velocities. Nine over the ten binaries have their three dimensional orbit well constrained. Four of them are known colliding wind, non-thermal radio emitters, and thus constitute valuable targets for future high angular resolution radio imaging. Two binaries break the correlation between period and eccentricity tentatively observed in previous studies. It suggests either that massive star formation produce a wide range of systems, or that several binary formation mechanisms ...

  12. Be discs in binary systems I. Coplanar orbits

    CERN Document Server

    Panoglou, Despina; Vieira, Rodrigo G; Cyr, Isabelle H; Jones, Carol E; Okazaki, Atsuo T; Rivinius, Thomas

    2016-01-01

    Be stars are surrounded by outflowing circumstellar matter structured in the form of decretion discs. They are often members of binary systems, where it is expected that the decretion disc interacts both radiatively and gravitationally with the companion. In this work we study how various orbital (period, mass ratio, eccentricity) and disc (viscosity) parameters affect the disc structure in coplanar systems. We simulate such binaries with the use of a smoothed particle hydrodynamics code. The main effects of the secondary on the disc are its truncation and the accumulation of material inwards of truncation. In circular or nearly circular prograde orbits, the disc maintains a rotating, constant in shape, configuration, which is locked to the orbital phase. The disc is smaller in size, more elongated and more massive for low viscosity parameter, small orbital separation and/or high mass ratio. Highly eccentric orbits are more complex, with the disc structure and total mass strongly dependent on the orbital phas...

  13. Bayesian Statistical Approach To Binary Asteroid Orbit Determination

    Science.gov (United States)

    Dmitrievna Kovalenko, Irina; Stoica, Radu S.

    2015-08-01

    Orbit determination from observations is one of the classical problems in celestial mechanics. Deriving the trajectory of binary asteroid with high precision is much more complicate than the trajectory of simple asteroid. Here we present a method of orbit determination based on the algorithm of Monte Carlo Markov Chain (MCMC). This method can be used for the preliminary orbit determination with relatively small number of observations, or for adjustment of orbit previously determined.The problem consists on determination of a conditional a posteriori probability density with given observations. Applying the Bayesian statistics, the a posteriori probability density of the binary asteroid orbital parameters is proportional to the a priori and likelihood probability densities. The likelihood function is related to the noise probability density and can be calculated from O-C deviations (Observed minus Calculated positions). The optionally used a priori probability density takes into account information about the population of discovered asteroids. The a priori probability density is used to constrain the phase space of possible orbits.As a MCMC method the Metropolis-Hastings algorithm has been applied, adding a globally convergent coefficient. The sequence of possible orbits derives through the sampling of each orbital parameter and acceptance criteria.The method allows to determine the phase space of every possible orbit considering each parameter. It also can be used to derive one orbit with the biggest probability density of orbital elements.

  14. HIPPARCOS PHOTOCENTRIC ORBITS OF 72 SINGLE-LINED SPECTROSCOPIC BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Ren Shulin; Fu Yanning, E-mail: rensl@pmo.ac.cn, E-mail: fyn@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2013-03-15

    By fitting the Hipparcos Intermediate Astrometric Data (HIAD), photocentric orbits can be obtained for the single-lined spectroscopic binaries (SB1s). In previous work, a simplifying approximation used in the fitting process was that the photocenter coincides with the primary, but simple arguments based on a mass-luminosity relation show that this approximation will introduce non-negligible deviation into photocentric orbits of a few SB1s. By fitting the revised HIAD without the approximation, the present paper tries to provide reliable photocentric orbits for those SB1s in the 9th Catalogue of Orbits of Spectroscopic Binaries having a reliable spectroscopic orbit of period between 50 days and 3.2 years. After a stringent assessment and screening process, we finally accept the photocentric orbits of 72 systems. Among these results, 37 orbits are obtained here for the first time. So far, only three of these systems are resolved with a known relative orbit. For each of them, the paired photocentric and relative orbits are in reasonably good agreement. For the 25 systems with a main-sequence primary, the masses of component stars and the semimajor axes of relative orbits are estimated for the purpose of planning ground-based observations.

  15. Towards the field binary population: Influence of orbital decay on close binaries

    CERN Document Server

    Korntreff, Christina; Pfalzner, Susanne

    2012-01-01

    Surveys of the binary populations in the solar neighbourhood have shown that the periods of G- and M-type stars are log-normally distributed. However, observations of young binary populations suggest a log-uniform distribution. Clearly some process(es) change the period distribution over time. Most stars form in star clusters, in which two important dynamical processes occur: i) gas-induced orbital decay of embedded binary systems and ii) destruction of soft binaries in three-body interactions. The emphasis here is on orbital decay which has been largely neglected so far. Using a combination of Monte-Carlo and dynamical nbody modelling it is demonstrated here that the cluster dynamics destroys the number of wide binaries, but leaves short-period binaries basically undisturbed even for a initially log-uniform distribution. By contrast orbital decay significantly reduces the number and changes the properties of short-period binaries, but leaves wide binaries largely uneffected. Until now it was unclear whether ...

  16. Three-dimensional orbit and physical parameters of HD 6840

    International Nuclear Information System (INIS)

    HD 6840 is a double-lined visual binary with an orbital period of ∼7.5 years. By fitting the speckle interferometric measurements made by the 6 m BTA telescope and 3.5 m WIYN telescope, Balega et al. gave a preliminary astrometric orbital solution of the system in 2006. Recently, Griffin derived a precise spectroscopic orbital solution from radial velocities observed with OPH and Cambridge Coravel. However, due to the low precision of the determined orbital inclination, the derived component masses are not satisfying. By adding the newly collected astrometric data in the Fourth Catalog of Interferometric Measurements of Binary Stars, we give a three-dimensional orbit solution with high precision and derive the preliminary physical parameters of HD 6840 via a simultaneous fit including both astrometric and radial velocity measurements. (paper)

  17. Simplified solution to determination of a binary orbit

    OpenAIRE

    Asada, Hideki; Akasaka, Toshio; Kudoh, Kazuya

    2006-01-01

    We present a simplified solution to orbit determination of a binary system from astrometric observations. An exact solution was found by Asada, Akasaka and Kasai by assuming no observational errors. We extend the solution considering observational data. The generalized solution is expressed in terms of elementary functions, and therefore requires neither iterative nor numerical methods.

  18. Stable Conic-Helical Orbits of Planets around Binary Stars: Analytical Results

    Science.gov (United States)

    Oks, E.

    2015-05-01

    Studies of planets in binary star systems are especially important because it was estimated that about half of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges. One-planet binary star systems (OBSS) have a limited analogy to objects studied in atomic/molecular physics: one-electron Rydberg quasimolecules (ORQ). Specifically, ORQ, consisting of two fully stripped ions of the nuclear charges Z and Z‧ plus one highly excited electron, are encountered in various plasmas containing more than one kind of ion. Classical analytical studies of ORQ resulted in the discovery of classical stable electronic orbits with the shape of a helix on the surface of a cone. In the present paper we show that despite several important distinctions between OBSS and ORQ, it is possible for OBSS to have stable planetary orbits in the shape of a helix on a conical surface, whose axis of symmetry coincides with the interstellar axis; the stability is not affected by the rotation of the stars. Further, we demonstrate that the eccentricity of the stars’ orbits does not affect the stability of the helical planetary motion if the center of symmetry of the helix is relatively close to the star of the larger mass. We also show that if the center of symmetry of the conic-helical planetary orbit is relatively close to the star of the smaller mass, a sufficiently large eccentricity of stars’ orbits can switch the planetary motion to the unstable mode and the planet would escape the system. We demonstrate that such planets are transitable for the overwhelming majority of inclinations of plane of the stars’ orbits (i.e., the projections of the planet and the adjacent start on the plane of the sky coincide once in a while). This means that conic-helical planetary orbits at binary stars can be detected photometrically. We consider, as an example, Kepler-16 binary stars to provide illustrative numerical data on the possible parameters and the

  19. Orbital Architectures of Planet-Hosting Binary Systems

    Science.gov (United States)

    Dupuy, Trent J.; Kratter, Kaitlin M.

    2016-01-01

    We present the first results from our Keck AO astrometric monitoring of Kepler Prime Mission planet-hosting binary systems. Observational biases in exoplanet discovery have long left the frequency, properties, and provenance of planets in most binary systems largely unconstrained. Recent results from our ongoing survey of a volume-limited sample of Kepler planet hosts indicate that binary companions at solar-system scales of 20-100 AU suppress the occurrence of planetary systems at a rate of 30-100%. However, some planetary systems do survive in binaries, and determining these systems' orbital architectures is key to understanding why. As a demonstration of this new approach to testing ideas of planet formation, we present a detailed analysis of the triple star system Kepler-444 (HIP 94931) that hosts five Ganymede- to Mars-sized planets. By combining our high-precision astrometry with radial velocities from HIRES we discover a highly eccentric stellar orbit that would have made this a seemingly hostile site for planet formation. This either points to an extremely robust and efficient planet formation mechanism or a rare case of favorable initial conditions. Such broader implications will be addressed by determining orbital architectures for our larger statistical sample of Kepler planet-hosting systems that have stellar companions on solar system scales.

  20. Five New and Three Improved Mutual Orbits of Transneptunian Binaries

    CERN Document Server

    Grundy, W M; Nimmo, F; Roe, H G; Buie, M W; Porter, S B; Benecchi, S D; Stephens, D C; Levison, H F; Stansberry, J A

    2011-01-01

    We present three improved and five new mutual orbits of transneptunian binary systems (58534) Logos-Zoe, (66652) Borasisi-Pabu, (88611) Teharonhiawako-Sawiskera, (123509) 2000 WK183, (149780) Altjira, 2001 QY297, 2003 QW111, and 2003 QY90 based on Hubble Space Telescope and Keck 2 laser guide star adaptive optics observations. Combining the five new orbit solutions with 17 previously known orbits yields a sample of 22 mutual orbits for which the period P, semimajor axis a, and eccentricity e have been determined. These orbits have mutual periods ranging from 5 to over 800 days, semimajor axes ranging from 1,600 to 37,000 km, eccentricities ranging from 0 to 0.8, and system masses ranging from 2 x 10^17 to 2 x 10^22 kg. Based on the relative brightnesses of primaries and secondaries, most of these systems consist of near equal-sized pairs, although a few of the most massive systems are more lopsided. The observed distribution of orbital properties suggests that the most loosely-bound transneptunian binary syst...

  1. A census of transient orbital resonances encountered during binary inspiral

    CERN Document Server

    Ruangsri, Uchupol

    2013-01-01

    Transient orbital resonances have recently been identified as potentially important to the inspiral of small bodies into large black holes. These resonances occur as the inspiral evolves through moments in which two fundamental orbital frequencies, $\\Omega_\\theta$ and $\\Omega_r$, are in a small integer ratio to one another. Previous work has demonstrated that a binary's parameters are "kicked" each time the inspiral passes through a resonance, changing the orbit's characteristics relative to a model that neglects resonant effects. In this paper, we use exact Kerr geodesics coupled to an accurate but approximate model of inspiral to survey orbital parameter space and estimate how commonly one encounters long-lived orbital resonances. We find that the most important resonances last for a few hundred orbital cycles at mass ratio $10^{-6}$, and that resonances are almost certain to occur during the time that a large mass ratio binary would be a target of gravitational-wave observations. Resonances appear to be ub...

  2. Interacting Binaries with Eccentric Orbits. III. Orbital Evolution due to Direct Impact and Self-Accretion

    CERN Document Server

    Sepinsky, J F; Kalogera, V; Rasio, F A

    2010-01-01

    The rapid circularization and synchronization of the stellar components in an eccentric binary system at the onset of mass transfer is a fundamental assumption common to all binary stellar evolution and population synthesis codes, even though the validity of this assumption is questionable both theoretically and observationally. Here we calculate the evolution of the orbital elements of an eccentric binary through the direct three-body integration of a massive particle ejected through the inner Lagrangian point of the donor star at periastron. The trajectory of this particle leads to three possible outcomes: direct accretion onto the companion star within a single orbit, self-accretion back onto the donor star within a single orbit, or a quasi-periodic orbit around the companion star, possibly leading to the formation of a disk. We calculate the secular evolution of the binary orbit in the first two cases and conclude that direct impact accretion can increase as well as decrease the orbital semi-major axis an...

  3. Parallax and orbital effects in astrometric microlensing with binary sources

    CERN Document Server

    Nucita, A A; Ingrosso, G; Giordano, M; Manni, L

    2016-01-01

    In gravitational microlensing, binary systems may act as lenses or sources. Identifying lens binarity is generally easy especially in events characterized by caustic crossing since the resulting light curve exhibits strong deviations from smooth single-lensing light curve. On the contrary, light curves with minor deviations from a Paczy\\'nski behaviour do not allow one to identify the source binarity. A consequence of the gravitational microlensing is the shift of the position of the multiple image centroid with respect to the source star location - the so called astrometric microlensing signal. When the astrometric signal is considered, the presence of a binary source manifests with a path that largely differs from that expected for single-source events. Here, we investigate the astrometric signatures of binary sources taking into account their orbital motion and the parallax effect due to the Earth motion, which turn out not to be negligible in most cases. We also show that considering the above-mentioned e...

  4. Accurate and efficient waveforms for compact binaries on eccentric orbits

    CERN Document Server

    Huerta, E A; McWilliams, Sean T; O'Shaughnessy, Richard; Yunes, Nicolas

    2014-01-01

    Compact binaries that emit gravitational waves in the sensitivity band of ground-based detectors can have non-negligible eccentricities just prior to merger, depending on the formation scenario. We develop a purely analytic, frequency-domain model for gravitational waves emitted by compact binaries on orbits with small eccentricity, which reduces to the quasi-circular post-Newtonian approximant TaylorF2 at zero eccentricity and to the post-circular approximation of Yunes et al. (2009) at small eccentricity. Our model uses a spectral approximation to the (post-Newtonian) Kepler problem to model the orbital phase as a function of frequency, accounting for eccentricity effects up to ${\\cal{O}}(e^8)$ at each post-Newtonian order. Our approach accurately reproduces an alternative time-domain eccentric waveform model for eccentricities $e\\in [0, 0.4]$ and binaries with total mass less than 12 solar masses. As an application, we evaluate the signal amplitude that eccentric binaries produce in different networks of e...

  5. Shrinking binary and planetary orbits by Kozai cycles with tidal friction

    CERN Document Server

    Fabrycky, Daniel

    2007-01-01

    At least two arguments suggest that the orbits of a large fraction of binary stars and extrasolar planets shrank by 1-2 orders of magnitude after formation: (i) the physical radius of a star shrinks by a large factor from birth to the main sequence, yet many main-sequence stars have companions orbiting only a few stellar radii away, and (ii) in current theories of planet formation, the region within ~0.1 AU of a protostar is too hot and rarefied for a Jupiter-mass planet to form, yet many "hot Jupiters" are observed at such distances. We investigate orbital shrinkage by the combined effects of secular perturbations from a distant companion star (Kozai oscillations) and tidal friction. We integrate the relevant equations of motion to predict the distribution of orbital elements produced by this process. Binary stars with orbital periods of 0.1 to 10 days, with a median of ~2 d, are produced from binaries with much longer periods (10 d to 10^5 d), consistent with observations indicating that most or all short-p...

  6. Tidal torque induced by orbital decay in compact object binaries

    CERN Document Server

    Dall'Osso, Simone

    2012-01-01

    As we observe in the moon-earth system, tidal interactions in binaries can lead to angular momentum exchange. The presence of viscosity is generally regarded as the condition for such transfer to happen. In this paper, we how a dynamical mechanism can cause a persistent torque between the binary components, even for inviscid bodies. This preferentially occurs at the final stage of coalescence of compact binaries, when the orbit shrinks by gravitational waves on a timescale shorter than the viscous timescale. The total orbital energy transferred to the secondary is a few 10^(-3) of its binding energy. We further show that this persistent torque induces a differentially rotating quadrupolar perturbation. Specializing to the case of a neutron star, we find that the free energy associated with this non-equilibrium state can be at least ~ 5 \\times 10^(46) erg just prior to coalescence. This energy is likely stored in internal fluid motions, with a sizable amount of differential rotation. Thus, a preexisting magnet...

  7. Mass and orbit constraints of the gamma-ray binary LS 5039

    CERN Document Server

    Szalai, T; Kiss, L L; Matthews, J M; Vinkó, J; Kiss, Cs

    2011-01-01

    We present the results of space-based photometric and ground-based spectroscopic observing campaigns on the gamma-ray binary LS 5039. The new orbital and physical parameters of the system are similar to former results, except we found a lower eccentricity. Our MOST-data show that any broad-band optical photometric variability at the orbital period is below the 2 mmag level. Light curve simulations support the lower value of eccentricity and imply that the mass of the compact object is higher than 1.8 solar masses.

  8. Changes in the orbital periods of close binary stars

    International Nuclear Information System (INIS)

    A number of close binary stars show erratic changes in their orbital periods on time scales of order 5-10 yr. Recently it has been proposed that the period changes are the result of changes in the quadrupole moment of one star, caused in turn by an alteration of the internal structure of that star. Magnetic pressure, which either distorts the shape of the star or changes its tidally induced quadrupole moment, is suggested as the driving force behind the alteration. Here, the amount of energy required to distort one component of a binary and match the observed period changes is estimated. The rate at which energy is produced or lost is governed by the thermal time scale of the star, and the estimates indicate that the observed period changes would take at least 1000 yr for the tidal quadrupole mechanism, and of order 60 yr to match a period change in V471 Tau which took only 4 yr. 16 refs

  9. Circumbinary disk, an efficient medium extracting orbital angular momentum in close binaries

    Institute of Scientific and Technical Information of China (English)

    CHEN WenCong; ZENG QingGuo

    2009-01-01

    The loss of orbital angular momentum plays an important role in the mass transfer and orbital evolution of close binaries. The traditional mechanisms of orbital angular momentum loss consist of gravitational wave radiation, mass loss and magnetic braking. However, a small fraction of the mass outflow may form a thin circumbinary disk (CB disk) located in the orbital plane of the binary during mass exchange. The tide torques caused by the gravitational interaction between a CB disk and a binary system brake binary effectively, and extract the orbital angular momentum from the binary system. In this study, numerical calculations for the evolution of the white dwarf binary show that a CB disk is an efficient medium extracting orbital angular momentum even if the mass loss is very small. Finally, some theo-retical research and observational progress on CB disks are presented.

  10. Orbital evolution of mass-transferring eccentric binary systems. I. Phase-dependent evolution

    OpenAIRE

    Dosopoulou, Fani; Kalogera, Vicky

    2016-01-01

    Observations reveal that mass-transferring binary systems may have non-zero orbital eccentricities. The time-evolution of the orbital semi-major axis and eccentricity of mass-transferring eccentric binary systems is an important part of binary evolution theory and has been widely studied. However, various different approaches and assumptions on the subject have made the literature difficult to comprehend and comparisons between different orbital element time-evolution equations not easy to ma...

  11. Binary evolution using the theory of osculating orbits: conservative Algol evolution

    OpenAIRE

    Davis, P J; Siess, L.; Deschamps, R.

    2014-01-01

    Our aim is to calculate the evolution of Algol binaries within the framework of the osculating orbital theory, which considers the perturbing forces acting on the orbit of each star arising from mass exchange via Roche lobe overflow (RLOF). The scheme is compared to results calculated from a `classical' prescription. Using our stellar binary evolution code BINSTAR, we calculate the orbital evolution of Algol binaries undergoing case A and case B mass transfer, by applying the osculating schem...

  12. Physical parameters of eclipsing binary components, discovered by STEREO

    Science.gov (United States)

    Belcheva, Maya; Markov, Haralambi; Tsvetanov, Zlatan; Iliev, Ilian; Stateva, Ivanka

    2015-01-01

    Using photometric observations made with the Heliospheric Imager 1 onboard NASA's STEREO mission a list of eclipsing binary systems was prepared which can be observed with the Coude spectrograph of the National Astronomical Observatory of Bulgaria, Smolyan, Bulgaria. The epoch and orbital period of each system were determined. The full complement of data consist of light curves extracted from STEREO HI-1 cameras photometry, wide coverage Echelle spectra obtained with the ARCES spectrograph at Apache Point Observatory, New Mexico, USA, for stellar characterization and Coude spectra with R ≈ 15000 and R ≈ 30000 obtained at NAO Rozhen for radial velocity curves. Here we present preliminary results from applying the Wilson-Devinney models for the determination of some physical parameters of three SB2 eclipsing binary systems - HD 103694, HD 185990, and HD 214688.

  13. Physical parameters of components in close binary systems: V

    CERN Document Server

    Zola, S; Zakrzewski, B; Kjurkchieva, D P; Marchev, D V; Baran, A; Rucinski, S M; Ogloza, W; Siwak, M; Koziel, D; Drozdz, M; Pokrzywka, B

    2009-01-01

    The paper presents combined spectroscopic and photometric orbital solutions for ten close binary systems: CN And, V776 Cas, FU Dra, UV Lyn, BB Peg, V592 Per, OU Ser, EQ Tau, HN UMa and HT Vir. The photometric data consist of new multicolor light curves, while the spectroscopy has been recently obtained within the radial velocity program at the David Dunlap Observatory (DDO). Absolute parameters of the components for these binary systems are derived. Our results confirm that CN And is not a contact system. Its configuration is semi-detached with the secondary component filling its Roche lobe. The configuration of nine other systems is contact. Three systems (V776 Cas, V592 Per and OU Ser) have high (44-77%) and six (FU Dra, UV Lyn, BB Peg, EQ Tau, HN UMa and HT Vir) low or intermediate (8-32%) fill-out factors. The absolute physical parameters are derived.

  14. Parallax and Orbital Effects in Astrometric Microlensing with Binary Sources

    Science.gov (United States)

    Nucita, A. A.; De Paolis, F.; Ingrosso, G.; Giordano, M.; Manni, L.

    2016-06-01

    In gravitational microlensing, binary systems may act as lenses or sources. Identifying lens binarity is generally easy, in particular in events characterized by caustic crossing since the resulting light curve exhibits strong deviations from a smooth single-lensing light curve. In contrast, light curves with minor deviations from a Paczyński behavior do not allow one to identify the source binarity. A consequence of gravitational microlensing is the shift of the position of the multiple image centroid with respect to the source star location — the so-called astrometric microlensing signal. When the astrometric signal is considered, the presence of a binary source manifests with a path that largely differs from that expected for single source events. Here, we investigate the astrometric signatures of binary sources taking into account their orbital motion and the parallax effect due to the Earth’s motion, which turn out not to be negligible in most cases. We also show that considering the above-mentioned effects is important in the analysis of astrometric data in order to correctly estimate the lens-event parameters.

  15. Near-earth binaries and triples: Origin and evolution of spin-orbital properties

    OpenAIRE

    J. Fang; Margot, JL

    2012-01-01

    In the near-Earth asteroid population, binary and triple systems have been discovered with mutual orbits that have significant eccentricities as well as large semimajor axes. All known systems with eccentric orbits and all widely separated primary-satellite pairs have rapidly rotating satellites. Here, we study processes that can elucidate the origin of these spin-orbital properties. Binary formation models based on rotational fissioning can reproduce asynchronous satellites on orbits with hi...

  16. Conic-Helical Orbits of Planets around Binary Stars do not Exist

    CERN Document Server

    Egan, Greg

    2015-01-01

    Oks proposes the existence of stable planetary orbits around binary stars, in the shape of a helix on a conical surface whose axis of symmetry coincides with the interstellar axis. We show that planetary orbits initially meeting this description will not continue to do so as the binary pair rotates.

  17. Fast and Accurate Computation Tools for Gravitational Waveforms from Binary Sistems with any Orbital Eccentricity

    CERN Document Server

    Pierro, V; Spallicci, A D; Laserra, E; Recano, F

    2001-01-01

    The relevance of orbital eccentricity in the detection of gravitational radiation from (steady state) binary stars is emphasized. Computationnally effective fast and accurate)tools for constructing gravitational wave templates from binary stars with any orbital eccentricity are introduced, including tight estimation criteria of the pertinent truncation and approximation errors.

  18. The third post-Newtonian gravitational waveforms for compact binary systems in general orbits: instantaneous terms

    CERN Document Server

    Mishra, Chandra Kant; Iyer, Bala R

    2015-01-01

    We compute the instantaneous contributions to the spherical harmonic modes of gravitational waveforms from compact binary systems in general orbits up to the third post-Newtonian order. We further extend these results for compact binaries in quasi-elliptical orbits using the 3PN quasi-Keplerian representation of the conserved dynamics of compact binaries in eccentric orbits. Using the multipolar post-Minkowskian formalism, starting from the different mass and current type multipole moments, we compute the spin weighted spherical harmonic decomposition of the instantaneous part of the gravitational waveform. These are terms which are functions of the retarded time and do not depend on the history of the binary evolution. Together with the hereditary part, which depends on the binary's dynamical history, these waveforms form the basis for construction of accurate templates for the detection of gravitational wave signals from binaries moving in quasi-elliptical orbits.

  19. Spectroscopic orbital elements for the helium-rich subdwarf binary PG 1544+488

    Science.gov (United States)

    Şener, H. T.; Jeffery, C. S.

    2014-05-01

    PG 1544+488 is an exceptional short-period spectroscopic binary containing two subdwarf B stars. It is also exceptional because the surfaces of both components are extremely helium-rich. We present a new analysis of spectroscopy of PG 1544+488 obtained with the William Herschel Telescope. We obtain improved orbital parameters and atmospheric parameters for each component. The orbital period P = 0.496 ± 0.002 d, dynamical mass ratio MB/MA = 0.911 ± 0.015 and spectroscopic radius ratio RB/RA = 0.939 ± 0.004 indicate a binary consisting of nearly identical twins. The data are insufficient to distinguish any difference in surface composition between the components, which are slightly metal-poor (1/3 solar) and carbon-rich (0.3 per cent by number). The latter indicates that the hotter component, at least, has ignited helium. The best theoretical model for the origin of PG 1544+488 is by the ejection of a common envelope from a binary system in which both components are giants with helium cores of nearly equal mass. Since precise tuning is necessary to yield two helium cores of similar masses at the same epoch, the mass ratio places very tight constraints on the dimensions of the progenitor system and on the physics of the common-envelope ejection mechanism.

  20. Time-domain inspiral templates for spinning compact binaries in quasi-circular orbits described by their orbital angular momenta

    International Nuclear Information System (INIS)

    We present a prescription to compute the time-domain gravitational wave (GW) polarization states associated with spinning compact binaries inspiraling along quasi-circular orbits. We invoke the orbital angular momentum L rather than its Newtonian counterpart LN to describe the binary orbits while the two spin vectors are freely specified in an inertial frame associated with the initial direction of the total angular momentum. We show that the use of L to describe the orbits leads to additional 1.5PN order amplitude contributions to the two GW polarization states compared to the LN-based approach and discuss few implications of our approach. Furthermore, we provide a plausible prescription for GW phasing based on certain theoretical considerations and which may be treated as the natural circular limit to GW phasing for spinning compact binaries in inspiraling eccentric orbits (Gopakumar A and Schäfer G 2011 Phys. Rev. D 84 124007). (paper)

  1. The Five Planets in the Kepler-296 Binary System All Orbit the Primary: A Statistical and Analytical Analysis

    OpenAIRE

    Barclay, Thomas; Quintana, Elisa V.; Adams, Fred C.; Ciardi, David R.; Huber, Daniel; Foreman-Mackey, Daniel; Montet, Benjamin T.; Caldwell, Douglas

    2015-01-01

    Kepler-296 is a binary star system with two M-dwarf components separated by 0.2 arcsec. Five transiting planets have been confirmed to be associated with the Kepler-296 system; given the evidence to date, however, the planets could in principle orbit either star. This ambiguity has made it difficult to constrain both the orbital and physical properties of the planets. Using both statistical and analytical arguments, this paper shows that all five planets are highly likely to orbit the primary...

  2. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    Energy Technology Data Exchange (ETDEWEB)

    Marchis, F.; Cuk, M. [Carl Sagan Center at the SETI Institute, Mountain View, CA 94043 (United States); Durech, J. [Astronomical Institute, Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic); Castillo-Rogez, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vachier, F.; Berthier, J. [IMCCE-Obs de Paris, F-75014 Paris (France); Wong, M. H.; Kalas, P.; Duchene, G. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Van Dam, M. A. [Flat Wavefronts, Christchurch 8140 (New Zealand); Hamanowa, H. [Hamanowa Observatory, Motomiya, Fukushima 969-1204 (Japan); Viikinkoski, M., E-mail: fmarchis@seti.org [Tampere University of Technology, FI-33101 Tampere (Finland)

    2014-03-10

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.

  3. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    International Nuclear Information System (INIS)

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin

  4. Orbital Period Variations in Eclipsing Post Common Envelope Binaries

    CERN Document Server

    Parsons, S G; Copperwheat, C M; Dhillon, V S; Littlefair, S P; Hickman, R D G; Maxted, P F L; Gänsicke, B T; Unda-Sanzana, E; Colque, J P; Barraza, N; Sánchez, N; Monard, L A G

    2010-01-01

    We present high speed ULTRACAM photometry of the eclipsing post common envelope binaries DE CVn, GK Vir, NN Ser, QS Vir, RR Cae, RX J2130.6+4710, SDSS 0110+1326 and SDSS 0303+0054 and use these data to measure precise mid-eclipse times in order to detect any period variations. We detect a large (~ 250 sec) departure from linearity in the eclipse times of QS Vir which Applegate's mechanism fails to reproduce by an order of magnitude. The only mechanism able to drive this period change is a third body in a highly elliptical orbit. However, the planetary/sub-stellar companion previously suggested to exist in this system is ruled out by our data. Our eclipse times show that the period decrease detected in NN Ser is continuing, with magnetic braking or a third body the only mechanisms able to explain this change. The planetary/sub-stellar companion previously suggested to exist in NN Ser is also ruled out by our data. Our precise eclipse times also lead to improved ephemerides for DE CVn and GK Vir. The width of a...

  5. On the orbital parameters of Be/X-ray binaries in the Small Magellanic Cloud

    CERN Document Server

    Townsend, L J; Corbet, R H D; Hill, A B

    2011-01-01

    The orbital motion of a neutron star about its optical companion presents a window through which to study the orbital parameters of that binary system. This has been used extensively in the Milky Way to calculate these parameters for several high-mass X-ray binaries. Using several years of RXTE PCA data, we derive the orbital parameters of four Be/X-ray binary systems in the SMC, increasing the number of systems with orbital solutions by a factor of three. We find one new orbital period, confirm a second and discuss the parameters with comparison to the Galactic systems. Despite the low metallicity in the SMC, these binary systems sit amongst the Galactic distribution of orbital periods and eccentricities, suggesting that metallicity may not play an important role in the evolution of high-mass X-ray binary systems. A plot of orbital period against eccentricity shows that the supergiant, Be and low eccentricity OB transient systems occupy separate regions of the parameter space; akin to the separated regions o...

  6. The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries

    CERN Document Server

    Brown, Warren R; Kilic, Mukremin; Kenyon, Scott J; Prieto, Carlos Allende

    2016-01-01

    We present the discovery of 15 extremely low mass (5 < log{g} < 7) white dwarf candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted ELM Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 Msun mean and 0.25 Msun dispersion. Thus extremely low mass white dwarfs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the white dwarf binaries have a total mass below the Chandrasekhar mass and thus are not Type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive white dwarfs and stable mass transfer AM CVn binaries.

  7. Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

    DEFF Research Database (Denmark)

    Van Eylen, Vincent; Winn, Joshua N.; Albrecht, Simon

    2016-01-01

    . Here we seek evidence for the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler. This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure...

  8. The Five Planets in the Kepler-296 Binary System All Orbit the Primary: A Statistical and Analytical Analysis

    CERN Document Server

    Barclay, Thomas; Adams, Fred C; Ciardi, David R; Huber, Daniel; Foreman-Mackey, Daniel; Montet, Benjamin T; Caldwell, Douglas

    2015-01-01

    Kepler-296 is a binary star system with two M-dwarf components separated by 0.2 arcsec. Five transiting planets have been confirmed to be associated with the Kepler-296 system; given the evidence to date, however, the planets could in principle orbit either star. This ambiguity has made it difficult to constrain both the orbital and physical properties of the planets. Using both statistical and analytical arguments, this paper shows that all five planets are highly likely to orbit the primary star in this system. We performed a Markov-Chain Monte Carlo simulation using a five transiting planet model, leaving the stellar density and dilution with uniform priors. Using importance sampling, we compared the model probabilities under the priors of the planets orbiting either the brighter or the fainter component of the binary. A model where the planets orbit the brighter component, Kepler-296A, is strongly preferred by the data. Combined with our assertion that all five planets orbit the same star, the two outer p...

  9. Equilibrium, Stability and Orbital Evolution of Close Binary Systems

    CERN Document Server

    Lai, D; Shapiro, S L

    1993-01-01

    We present a new analytic study of the equilibrium and stability properties of close binary systems containing polytropic components. Our method is based on the use of ellipsoidal trial functions in an energy variational principle. We consider both synchronized and nonsynchronized systems, constructing the compressible generalizations of the classical Darwin and Darwin-Riemann configurations. Our method can be applied to a wide variety of binary models where the stellar masses, radii, spins, entropies, and polytropic indices are all allowed to vary over wide ranges and independently for each component. We find that both secular and dynamical instabilities can develop before a Roche limit or contact is reached along a sequence of models with decreasing binary separation. High incompressibility always makes a given binary system more susceptible to these instabilities, but the dependence on the mass ratio is more complicated. As simple applications, we construct models of double degenerate systems and of low-ma...

  10. On the Physical Processes in Contact Binary Systems

    Institute of Scientific and Technical Information of China (English)

    Run-Qian Huang; Han-Feng Song; Shao-Lan Bi

    2007-01-01

    Three important physical processes occurring in contact binary systems are studied.The first one is the effect of spin, orbital rotation and tide on the structure of the components,which includes also the effect of meridian circulation on the mixing of the chemical elements in the components. The second one is the mass and energy exchange between the components.To describe the energy exchange, a new approach is introduced based on the understanding that the exchange is due to the release of the potential, kinetic and thermal energy of the exchanged mass. The third is the loss of mass and angular momentum through the outer Lagrangian point. The rate of mass loss and the angular momentum carried away by the lost mass are discussed. To show the effects of these processes, we follow the evolution of a binary system consisting of a 12M⊙ and a 5M⊙ star with mass exchange between the components and mass loss via the outer Lagrangian point, both with and without considering the effects of rotation and tide. The result shows that the effect of rotation and tide advances the start of the semi-detached and the contact phases, and delays the end of the hydrogen-burning phase of the primary. Furthermore, it can change not only the occurrence of mass and angular momentum loss via the outer Lagrangian point, but also the contact or semi-contact status of the system. Thus, this effect can result in the special phenomenon of short-term variations occurring over a slow increase of the orbital period. The occurrence of mass and angular momentum loss via the outer Lagrangian point can affect the orbital period of the system significantly, but this process can be influenced, even suppressed out by the effect of rotation and tide. The mass and energy exchange occurs in the common envelope. The net result of the mass exchange process is a mass transfer from the primary to the secondary during the whole contact phase.

  11. Orbital Evolution of Mass-transferring Eccentric Binary Systems. I. Phase-dependent Evolution

    Science.gov (United States)

    Dosopoulou, Fani; Kalogera, Vicky

    2016-07-01

    Observations reveal that mass-transferring binary systems may have non-zero orbital eccentricities. The time evolution of the orbital semimajor axis and eccentricity of mass-transferring eccentric binary systems is an important part of binary evolution theory and has been widely studied. However, various different approaches to and assumptions on the subject have made the literature difficult to comprehend and comparisons between different orbital element time evolution equations not easy to make. Consequently, no self-consistent treatment of this phase has ever been included in binary population synthesis codes. In this paper, we present a general formalism to derive the time evolution equations of the binary orbital elements, treating mass loss and mass transfer as perturbations of the general two-body problem. We present the self-consistent form of the perturbing acceleration and phase-dependent time evolution equations for the orbital elements under different mass loss/transfer processes. First, we study the cases of isotropic and anisotropic wind mass loss. Then, we proceed with non-isotropic ejection and accretion in a conservative as well as a non-conservative manner for both point masses and extended bodies. We compare the derived equations with similar work in the literature and explain the existing discrepancies.

  12. Orbital Parameters of Binary Radio Pulsars : Revealing Their Structure, Formation, Evolution and Dynamic History

    CERN Document Server

    Bagchi, Manjari

    2010-01-01

    Orbital parameters of binary radio pulsars reveal the history of the pulsars' formation and evolution including dynamic interactions with other objects. Advanced technology has enabled us to determine these orbital parameters accurately in most of the cases. Determination of post-Keplerian parameters of double neutron star binaries (especially of the double pulsar) provide clean tests of GTR and in the future may lead us to constrain the dense matter EoS. For binary pulsars with MS or WD companions, knowledge about the values of the orbital parameters as well as of the spin periods and the masses of the pulsars and the companions might be useful to understand the evolutionary history of the systems. As accreting neutron star binaries lead to orbit circularization due to the tidal coupling during accretion, their descendants i.e. binary MSPs are expected to be in circular orbits. On the other hand, dense stellar environments inside globular clusters (GCs) cause different types of interactions of single stars w...

  13. Orbit and spin evolution of synchronous binary stars on the main sequence

    Institute of Scientific and Technical Information of China (English)

    Lin-Sen Li

    2012-01-01

    A set of synchronous equations are derived from a set of non-synchronous equations.The analytical solutions are given by solving the set of differential equations.The results of the evolutionary trend of the spin-orbit interaction are that the semi-major axis gradually shrinks with time; the orbital eccentricity gradually decreases with time until orbital circularization occurs; the orbital period gradually shortens with time and the rotational angular velocity of the primary component gradually speeds up with time before the orbit achieves circularization.The theoretical results are applied to evolution of the orbit and spin of synchronous binary stars Algol A and B that are on the main sequence.The circularization time,lifetime and the evolutionary numerical solutions of orbit and spin when circularization time occurs are estimated for Algol A and B.

  14. Orbital evolution of mass-transferring eccentric binary systems. I. Phase-dependent evolution

    CERN Document Server

    Dosopoulou, Fani

    2016-01-01

    Observations reveal that a large amount of close binary systems have a finite eccentricity. The time-evolution of the orbital semi-major axis and eccentricity of mass-transferring eccentric binary systems is an important part of binary evolution theory and has been widely studied. However, various different approaches and assumptions on the subject have made the literature difficult to comprehend and comparisons between different orbital element time-evolution equations not easy to make. Consequently, no self-consistent treatment of this phase has been ever included in binary population synthesis codes. In this paper, we present a general formalism to derive the time-evolution equations of the binary orbital elements, treating mass-loss and mass-transfer as perturbations to the general two-body problem. We present the self-consistent form of the perturbing acceleration and the phase-dependent time-evolution equations for the orbital elements under different mass-loss/transfer processes. First, we study the ca...

  15. SPECKLE INTERFEROMETRY AND ORBITS OF 'FAST' VISUAL BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Tokovinin, Andrei, E-mail: atokovinin@ctio.noao.edu [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile)

    2012-08-15

    Results of speckle observations at the 4.1 m SOAR telescope in 2012 (158 measures of 121 systems, 27 non-resolutions) are reported. The aim is to follow fast orbital motion of recently discovered or neglected close binaries and sub-systems. Here, eight previously known orbits are defined better, two more are completely revised, and five orbits are computed for the first time. Using differential photometry from Hipparcos or speckle and the standard relation between mass and absolute magnitude, the component's masses and dynamical parallaxes are estimated for all 15 systems with new or updated orbits. Two astrometric binaries HIP 54214 and 56245 are resolved here for the first time, another eight are measured. We highlight several unresolved pairs that may actually be single despite multiple historic measures, such as 104 Tau and f Pup AB. Continued monitoring is needed to understand those enigmatic cases.

  16. Binary neutron star merger simulations with different initial orbital frequency and equation of state

    Science.gov (United States)

    Maione, F.; De Pietri, R.; Feo, A.; Löffler, F.

    2016-09-01

    We present results from three-dimensional general relativistic simulations of binary neutron star coalescences and mergers using public codes. We considered equal mass models where the baryon mass of the two neutron stars is 1.4{M}ȯ , described by four different equations of state (EOS) for the cold nuclear matter (APR4, SLy, H4, and MS1; all parametrized as piecewise polytropes). We started the simulations from four different initial interbinary distances (40,44.3,50, and 60 km), including up to the last 16 orbits before merger. That allows us to show the effects on the gravitational wave (GW) phase evolution, radiated energy and angular momentum due to: the use of different EOS, the orbital eccentricity present in the initial data and the initial separation (in the simulation) between the two stars. Our results show that eccentricity has a major role in the discrepancy between numerical and analytical waveforms until the very last few orbits, where ‘tidal’ effects and missing high-order post-Newtonian coefficients also play a significant role. We test different methods for extrapolating the GW signal extracted at finite radii to null infinity. We show that an effective procedure for integrating the Newman–Penrose {\\psi }4 signal to obtain the GW strain h is to apply a simple high-pass digital filter to h after a time domain integration, where only the two physical motivated integration constants are introduced. That should be preferred to the more common procedures of introducing additional integration constants, integrating in the frequency domain or filtering {\\psi }4 before integration.

  17. Orbital Period Variations in Eclipsing Post Common Envelope Binaries

    OpenAIRE

    Parsons, S. G.; Marsh, T. R.; Copperwheat, C. M.; Dhillon, V S; Littlefair, S. P.; Hickman, R. D. G.; Maxted, P. F. L.; Gänsicke, B. T.; Unda-Sanzana, E.; Colque, J. P.; Barraza, N.; Sánchez, N.; Monard, L. A. G.

    2010-01-01

    We present high speed ULTRACAM photometry of the eclipsing post common envelope binaries DE CVn, GK Vir, NN Ser, QS Vir, RR Cae, RX J2130.6+4710, SDSS 0110+1326 and SDSS 0303+0054 and use these data to measure precise mid-eclipse times in order to detect any period variations. We detect a large (~ 250 sec) departure from linearity in the eclipse times of QS Vir which Applegate's mechanism fails to reproduce by an order of magnitude. The only mechanism able to drive this period change is a thi...

  18. Probing evolution of binaries influenced by the spin–orbit resonances

    International Nuclear Information System (INIS)

    We evolve isolated comparable mass spinning compact binaries experiencing Schnittman’s post-Newtonian spin–orbit resonances in an inertial frame associated with j0, the initial direction of the total angular momentum. We argue that accurate gravitational wave (GW) measurements of the initial orientations of the two spins and orbital angular momentum from j0 should allow us to distinguish between the two possible families of spin–orbit resonances. Therefore, these measurements have the potential to provide direct observational evidence of possible binary formation scenarios. The above statements should also apply for binaries that do not remain in a resonant plane when they become detectable by GW interferometers. The resonant plane, characterized by the vanishing scalar triple product involving the two spins and the orbital angular momentum, naturally appears in the one parameter family of equilibrium solutions, discovered by Schnittman. We develop a prescription to compute the time-domain inspiral templates for binaries residing in these resonant configurations and explore their preliminary data analysis consequences. (paper)

  19. Orbital period changes and the higher-order multiplicity fraction amongst SuperWASP eclipsing binaries

    CERN Document Server

    Lohr, M E; Payne, S G; West, R G; Wheatley, P J

    2015-01-01

    Orbital period changes of binary stars may be caused by the presence of a third massive body in the system. Here we have searched the archive of the Wide Angle Search for Planets (SuperWASP) project for evidence of period variations in 13927 eclipsing binary candidates. Sinusoidal period changes, strongly suggestive of third bodies, were detected in 2% of cases; however, linear period changes were observed in a further 22% of systems. We argue on distributional grounds that the majority of these apparently linear changes are likely to reflect longer-term sinusoidal period variations caused by third bodies, and thus estimate a higher-order multiplicity fraction of 24% for SuperWASP binaries, in good agreement with other recent figures for the fraction of triple systems amongst binary stars in general.

  20. Accretion and Orbital Inspiral in Gas-assisted Supermassive Black Hole Binary Mergers

    Science.gov (United States)

    Rafikov, Roman R.

    2016-08-01

    Many galaxies are expected to harbor binary supermassive black holes (SMBHs) in their centers. Their interaction with the surrounding gas results in the accretion and exchange of angular momentum via tidal torques, facilitating binary inspiral. Here, we explore the non-trivial coupling between these two processes and analyze how the global properties of externally supplied circumbinary disks depend on the binary accretion rate. By formulating our results in terms of the angular momentum flux driven by internal stresses, we come up with a very simple classification of the possible global disk structures, which differ from the standard constant \\dot{M} accretion disk solution. The suppression of accretion by the binary tides, leading to a significant mass accumulation in the inner disk, accelerates binary inspiral. We show that once the disk region strongly perturbed by the viscously transmitted tidal torque exceeds the binary semimajor axis, the binary can merge in less than its mass-doubling time due to accretion. Thus, unlike the inspirals driven by stellar scattering, the gas-assisted merger can occur even if the binary is embedded in a relatively low-mass disk (lower than its own mass). This is important for resolving the “last parsec” problem for SMBH binaries and understanding powerful gravitational wave sources in the universe. We argue that the enhancement of accretion by the binary found in some recent simulations cannot persist for a long time and should not affect the long-term orbital inspiral. We also review existing simulations of SMBH binary–disk coupling and propose a numerical setup which is particularly well suited to verifying our theoretical predictions.

  1. Frequency and time domain inspiral templates for comparable mass compact binaries in eccentric orbits

    CERN Document Server

    Tanay, Sashwat; Gopakumar, Achamveedu

    2016-01-01

    Inspiraling compact binaries with non-negligible orbital eccentricities are plausible gravitational wave (GW) sources for the upcoming network of GW observatories. In this paper, we present two prescriptions to compute post-Newtonian (PN) accurate inspiral templates for such binaries. First, we adapt and extend the post-circular scheme of Yunes {\\it et al.} [Phys. Rev. D 80, 084001 (2009)] to obtain a Fourier-domain inspiral approximant that incorporates the effects of PN-accurate orbital eccentricity evolution. This results in a fully analytic frequency-domain inspiral waveform with Newtonian amplitude and 2PN order Fourier phase while incorporating eccentricity effects up to sixth order at each PN order. The importance of incorporating eccentricity evolution contributions to the Fourier phase in a PN consistent manner is also demonstrated. Second, we present an accurate and efficient prescription to incorporate orbital eccentricity into the quasi-circular time-domain {\\texttt{TaylorT4}} approximant at 2PN o...

  2. The ELM Survey. VII. Orbital Properties of Low-Mass White Dwarf Binaries

    Science.gov (United States)

    Brown, Warren R.; Gianninas, A.; Kilic, Mukremin; Kenyon, Scott J.; Allende Prieto, Carlos

    2016-02-01

    We present the discovery of 15 extremely low-mass (5\\lt {log}g\\lt 7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted extremely low-mass Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 M⊙ mean and 0.25 M⊙ dispersion. Thus extremely low-mass WDs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD binaries have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn binaries. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

  3. Extremely fast orbital decay of the black hole X-ray binary Nova Muscae 1991

    CERN Document Server

    Hernández, J I González; Rebolo, R; Casares, J

    2016-01-01

    We present new medium-resolution spectroscopic observations of the black hole X-ray binary Nova Muscae 1991 taken with X-Shooter spectrograph installed at the 8.2m-VLT telecope. These observations allow us to measure the time of inferior conjunction of the secondary star with the black hole in this system that, together with previous measurements, yield an orbital period decay of $\\dot P=-20.7\\pm12.7$ ms yr$^{-1}$ ($-24.5\\pm15.1$ $\\mu $s per orbital cycle). This is significantly faster than those previously measured in the other black hole X-ray binaries A0620-00 and XTE J1118+480. No standard black hole X-ray binary evolutionary model is able to explain this extremely fast orbital decay. At this rate, the secondary star would reach the event horizon (as given by the Schwarzschild radius of about 32 km) in roughly 2.7 Myr. This result has dramatic implications on the evolution and lifetime of black hole X-ray binaries.

  4. 2.5PN kick from black-hole binaries in circular orbit: Nonspinning case

    CERN Document Server

    Mishra, Chandra Kant; Iyer, Bala R

    2013-01-01

    Using the Multipolar post-Minskowskian formalism, we compute the linear momentum flux from black-hole binaries in circular orbits and having no spins. The total linear momentum flux contains various types of instantaneous (which are functions of the retarded time) and hereditary (which depends on the dynamics of the binary in the past) terms both of which are analytically computed. In addition to the inspiral contribution, we use a simple model of plunge to compute the kick or recoil accumulated during this phase.

  5. Spectra disentangling applied to the Hyades binary Theta^2 Tau AB: new orbit, orbital parallax and component properties

    CERN Document Server

    Torres, K B V; Frémat, Y; Hensberge, H; Lebreton, Y; Y.,; Skoda, P

    2010-01-01

    Theta^2 Tauri is a detached and single-lined interferometric-spectroscopic binary as well as the most massive binary system of the Hyades cluster. The system revolves in an eccentric orbit with a periodicity of 140.7 days. The secondary has a similar temperature but is less evolved and fainter than the primary. It is also rotating more rapidly. Since the composite spectra are heavily blended, the direct extraction of radial velocities over the orbit of component B was hitherto unsuccessful. Using high-resolution spectroscopic data recently obtained with the Elodie (OHP, France) and Hermes (ORM, La Palma, Spain) spectrographs, and applying a spectra disentangling algorithm to three independent data sets including spectra from the Oak Ridge Observatory (USA), we derived an improved spectroscopic orbit and refined the solution by performing a combined astrometric-spectroscopic analysis based on the new spectroscopy and the long-baseline data from the Mark III optical interferometer. As a result, the velocity amp...

  6. Einstein@Home Discovery of a PALFA Millisecond Pulsar in an Eccentric Binary Orbit

    CERN Document Server

    Knispel, B; Stappers, B W; Freire, P C C; Lazarus, P; Allen, B; Aulbert, C; Bock, O; Bogdanov, S; Brazier, A; Camilo, F; Cardoso, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J S; Eggenstein, H -B; Fehrmann, H; Ferdman, R; Hessels, J W T; Jenet, F A; Karako-Argaman, C; Kaspi, V M; van Leeuwen, J; Lorimer, D R; Lynch, R; Machenschalk, B; Madsen, E; McLaughlin, M A; Patel, C; Ransom, S M; Scholz, P; Siemens, X; Spitler, L G; Stairs, I H; Stovall, K; Swiggum, J K; Venkataraman, A; Wharton, R S; Zhu, W W

    2015-01-01

    We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 ($P=4.3$ ms) in a binary system with an eccentric ($e=0.08$) orbit in Pulsar ALFA survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 $M_\\odot$ and is most likely a white dwarf. Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities $e < 0.001$. However, four recently discovered binary MSPs have orbits with larger eccentricities ($0.03 < e < 0.4$); PSR J1950+2414 is only the fifth such system to be discovered. The upper limits for the the intrinsic spin period derivative and inferred surface magnetic field strength are comparable to those of the general MSP population. The large eccentricities of these systems are not compatible with the predictions of the standard recycling scenario: som...

  7. On angular momentum transfer in binary systems. [stellar orbital period change

    Science.gov (United States)

    Wilson, R. E.; Stothers, R.

    1975-01-01

    The maximum limit for the conversion of orbital angular momentum into rotational angular momentum of the mass-gaining component in a close binary system is derived. It is shown that this conversion process does not seriously affect the rate of orbital period change and can be neglected in computing the mass transfer rate. Integration of this limit over the entire accretion process results in a value for the maximum accumulated rotational angular momentum that is 3 to 4 times larger than that implied by the observed underluminosity of stars in such systems as Mu(1) Sco, V Pup, SX Aur, and V356 Sgr. It is suggested that shell stars and emission-line stars in binary systems may be produced when the core angular momentum is transferred into an envelope having a rotational angular momentum close to the maximum limit.-

  8. The final spin from binary black holes in quasi-circular orbits

    CERN Document Server

    Hofmann, Fabian; Rezzolla, Luciano

    2016-01-01

    We revisit the problem of predicting the spin magnitude and direction of the black hole resulting from the merger of two black holes with arbitrary masses and spins inspiralling in quasi-circular orbits. We do this by analyzing a catalog of 641 recent numerical-relativity simulations collected from the literature and spanning a large variety of initial conditions. By combining information from the post-Newtonian approximation, the extreme mass-ratio limit and perturbative calculations, we improve our previously proposed phenomenological formulae for the final remnant spin. In contrast with alternative suggestions in the literature, and in analogy with our previous expressions, the new formula is a simple algebraic function of the initial system parameters and is not restricted to binaries with spins aligned/anti-aligned with the orbital angular momentum, but can be employed for fully generic binaries. The accuracy of the new expression is significantly improved, especially for almost extremal progenitor spins...

  9. Ballistic orbits in Schwarzschild space-time and gravitational waves from EMR binary mergers

    International Nuclear Information System (INIS)

    We describe a special class of ballistic geodesics in Schwarzschild space-time, extending to the horizon in the infinite past and future of observer time, which are characterized by the property that they are in 1–1 correspondence, and completely degenerate in energy and angular momentum, with stable circular orbits. We derive analytic expressions for the source terms in the Regge–Wheeler and Zerilli–Moncrief equations for a point-particle moving on such a ballistic orbit, and compute the gravitational waves emitted during the infall in an extreme mass ratio black-hole binary coalescence. In this way a geodesic approximation to the plunge phase of compact binaries is obtained. (paper)

  10. Improved orbits and parallaxes for eight visual binaries with unrealistic previous masses using the Hipparcos parallax

    CERN Document Server

    Docobo, J A; Malkov, O Yu; Campo, P P; Chulkov, D A

    2016-01-01

    Improved orbits are presented for the visual binaries WDS 02366+1227, WDS 02434-6643, WDS 03244-1539, WDS 08507+1800, WDS 09128-6055, WDS 11532-1540, WDS 17375+2419, and WDS 22408-0333. The latest orbits for these binaries were demonstrating a great inconsistency between the systemic mass obtained through Kepler's Third Law and that calculated as a sum of their components' mass through standard mass-luminosity and mass-spectrum relationships. Our improvement allowed us to obtain consistent systemic masses for WDS 02434-6643 and WDS 09128-6055 without a need for changing the Hipparcos parallax. For the remaining 6 pairs, we suggest the use of their dynamical parallax as a reliable distance estimate unless more precise parallax is reported. Astrophysical and dynamical properties of individual objects are discussed.

  11. Line Shapes Emitted from Spiral Structures around Symmetric Orbits of Supermassive Binary Black Holes

    CERN Document Server

    Smailagić, Marijana

    2016-01-01

    Variability of active galactic nuclei is not well understood. One possible explanation is existence of supermassive binary black holes (SMBBH) in their centres. It is expected that major mergers are common in the Universe. It is expected that each supermassive black hole of every galaxy eventually finish as a SMBBH system in the core of newly formed galaxy. Here we model the emission line profiles of active galactic nuclei (AGN) assuming that the flux and emission line shapes variation are induced by supermassive binary black hole systems (SMBBH). We assume that accreting gas inside of circumbinary (CB) disk is photo ionized by mini accretion disk emission around each SMBBH. We calculate variations of emission line flux, shifts and shapes for different parameters of SMBBH orbits. We consider cases with different masses and inclinations for circular orbits and measure the effect to the shape of emission line profiles and flux variability.

  12. Line Shapes Emitted from Spiral Structures around Symmetric Orbits of Supermassive Binary Black Holes

    Indian Academy of Sciences (India)

    M. Smailagić; E. Bon

    2015-12-01

    Variability of active galactic nuclei is not well understood. One possible explanation is existence of supermassive binary black holes (SMBBH) in their centres. It is expected that major mergers are common in the Universe. It is expected that each supermassive black hole of every galaxy eventually finish as a SMBBH system in the core of newly formed galaxy. Here we model the emission line profiles of active galactic nuclei (AGN) assuming that the flux and emission line shape variations are induced by supermassive binary black hole systems (SMBBH). We assume that the accreting gas inside the circumbinary (CB) disk is photo ionized by mini accretion disk emission around each SMBBH. We calculate variations of emission line flux, shifts and shapes for different parameters of SMBBH orbits. We consider cases with different masses and inclinations for circular orbits and measure the effect to the shape of emission line profiles and flux variability.

  13. The Final Spin from Binary Black Holes in Quasi-circular Orbits

    Science.gov (United States)

    Hofmann, Fabian; Barausse, Enrico; Rezzolla, Luciano

    2016-07-01

    We revisit the problem of predicting the spin magnitude and direction of the black hole (BH) resulting from the merger of two BHs with arbitrary masses and spins inspiraling in quasi-circular orbits. We do this by analyzing a catalog of 619 recent numerical-relativity simulations collected from the literature and spanning a large variety of initial conditions. By combining information from the post-Newtonian approximation, the extreme mass-ratio limit, and perturbative calculations, we improve our previously proposed phenomenological formulae for the final remnant spin. In contrast with alternative suggestions in the literature, and in analogy with our previous expressions, the new formula is a simple algebraic function of the initial system parameters and is not restricted to binaries with spins aligned/anti-aligned with the orbital angular momentum but can be employed for fully generic binaries. The accuracy of the new expression is significantly improved, especially for almost extremal progenitor spins and for small mass ratios, yielding an rms error σ ≈ 0.002 for aligned/anti-aligned binaries and σ ≈ 0.006 for generic binaries. Our new formula is suitable for cosmological applications and can be employed robustly in the analysis of the gravitational waveforms from advanced interferometric detectors.

  14. A search for substellar objects orbiting the sdB eclipsing binary HS 0705+6700

    Science.gov (United States)

    Qian, S.-B.; Shi, G.; Zola, S.; Koziel-Wierzbowska, D.; Winiarski, M.; Szymanski, T.; Ogloza, W.; Li, L.-J.; Zhu, L.-Y.; Liu, L.; He, J.-J.; Liao, W.-P.; Zhao, E.-G.; Wang, J.-J.; Zhang, J.; Jiang, L.-Q.

    2013-12-01

    By using 78 newly determined timings of light minima together with those collected from the literature, we analysed the changes in the observed minus calculated (O-C) diagram in HS 0705+6700, a short-period (2.3 h) eclipsing binary that consists of a very hot subdwarf B-type (sdB) star and a very cool fully convective red dwarf. We confirmed the cyclic variation in the O-C and refined the parameters of the circumbinary brown dwarf (reported to orbit the binary system in 2009) by analysing the changes for the light travel time effect that arises from the gravitational influence of the third body. Our results indicate the lower mass limit of the third body to be M3 sin i' = 33.7(±1.6) MJup. This companion would be a brown dwarf if its orbital inclination is larger than 27.7° and it is orbiting the central eclipsing binary with an eccentricity e ˜ 0.2 at a separation of about 3.7(±0.1) au.

  15. Black Hole Spin-Orbit Misalignment in Galactic X-ray Binaries

    CERN Document Server

    Fragos, T; Rantsiou, E; Belczynski, K

    2010-01-01

    In black hole X-ray binaries, a misalignment between the spin axis of the black hole and the orbital angular momentum can occur during the supernova explosion that forms the compact object. In this letter we present population synthesis models of Galactic black hole X-ray binaries, and study the probability density function of the misalignment angle, and its dependence on our model parameters. In our modeling, we also take into account the evolution of misalignment angle due to accretion of material onto the black hole during the X-ray binary phase. The major factor that sets the misalignment angle for X-ray binaries is the natal kick that the black hole may receive at its formation. However, large kicks tend to disrupt binaries, while small kicks allow the formation of XRBs and naturally select systems with small misalignment angles. Our calculations predict that the majority (>67%) of Galactic field BH XRBs have rather small (>10 degrees) misalignment angles, while some systems may reach misalignment angles...

  16. WIYN open cluster study. LX. Spectroscopic binary orbits in NGC 6819

    Energy Technology Data Exchange (ETDEWEB)

    Milliman, Katelyn E.; Mathieu, Robert D.; Gosnell, Natalie M. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street Madison, WI 53706 (United States); Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Meibom, Søren [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Platais, Imants, E-mail: milliman@astro.wisc.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2014-08-01

    We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1° field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10{sup 4} days to be 22% ± 3% and a tidal circularization period of 6.2{sub −1.1}{sup +1.1} days for NGC 6819.

  17. DC CIRCUIT POWERED BY ORBITAL MOTION: MAGNETIC INTERACTIONS IN COMPACT OBJECT BINARIES AND EXOPLANETARY SYSTEMS

    International Nuclear Information System (INIS)

    The unipolar induction DC circuit model, originally developed by Goldreich and Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such a model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to the breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultracompact white dwarf binaries, we find that unipolar induction does not provide adequate energy dissipation to explain the observed X-ray luminosities of several sources. For exoplanetary systems containing close-in Jupiters or super-Earths, the magnetic torque and energy dissipation induced by the orbital motion are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 103 G.

  18. The Orbit of Transneptunian Binary Manwe and Thorondor and Their Upcoming Mutual Events

    Science.gov (United States)

    Grundy, W. M.; Benecchi, S. D.; Porter, S. B.; Noll, K. S.

    2014-01-01

    A new Hubble Space Telescope observation of the 7:4 resonant transneptunian binary system (385446) Manwe has shown that, of two previously reported solutions for the orbit of its satellite Thorondor, the prograde one is correct. The orbit has a period of 110.18 +/- 0.02 days, semimajor axis of 6670 +/- 40 km, and an eccentricity of 0.563 +/- 0.007. It will be viewable edge-on from the inner Solar System during 2015- 2017, presenting opportunities to observe mutual occultation and eclipse events. However, the number of observable events will be small, owing to the long orbital period and expected small sizes of the bodies relative to their separation. This paper presents predictions for events observable from Earth-based telescopes and discusses the associated uncertainties and challenges.

  19. X-ray Spectroscopy of the High Mass X-ray Binary Pulsar Centaurus X-3 over its Binary Orbit

    CERN Document Server

    Naik, Sachindra; Ali, Zulfikar

    2011-01-01

    We present a comprehensive spectral analysis of the high mass X-ray binary (HMXB) pulsar Centaurus X-3 with the Suzaku observatory covering nearly one orbital period. The light curve shows the presence of extended dips which are rarely seen in HMXBs. These dips are seen up to as high as ~40 keV. The pulsar spectra during the eclipse, out-of-eclipse, and dips are found to be well described by a partial covering power-law model with high energy cut-off and three Gaussian functions for 6.4 keV, 6.7 keV, and 6.97 keV iron emission lines. The dips in the light curve can be explained by the presence of an additional absorption component with high column density and covering fraction, the values of which are not significant during the rest of the orbital phases. The iron line parameters during the dips and eclipse are significantly different compared to those during the rest of the observation. During the dips, the iron line intensities are found to be lesser by a factor of 2--3 with significant increase in the line...

  20. Spectroscopic Orbital Elements for the Helium-Rich Subdwarf Binary PG1544+488

    CERN Document Server

    Şener, H Tuğça

    2014-01-01

    PG1544+488 is an exceptional short-period spectroscopic binary containing two subdwarf B stars. It is also exceptional because the surfaces of both components are extremely helium-rich. We present a new analysis of spectroscopy of PG1544+488 obtained with the William Herschel Telescope. We obtain improved orbital parameters and atmospheric parameters for each component. The orbital period $P=0.496\\pm0.002$\\,d, dynamical mass ratio $M_{\\rm B}/M_{\\rm A}=0.911\\pm0.015$, and spectroscopic radius ratio $R_{\\rm B}/R_{\\rm A}=0.939\\pm0.004$ indicate a binary consisting of nearly identical twins. The data are insufficient to distinguish any difference in surface composition between the components, which are slightly metal-poor (1/3 solar) and carbon-rich (0.3% by number). The latter indicates that the hotter component, at least, has ignited helium. The best theoretical model for the origin of PG1544+488 is by the ejection of a common envelope from a binary system in which both components are giants with helium cores o...

  1. Binary Orbits as the Driver of Gamma-Ray Emission and Mass Ejection in Classical Novae

    Science.gov (United States)

    Chomiuk, Laura; Linford, Justin D.; Yang, Jun; O'Brien, T. J.; Paragi, Zsolt; Mioduszewski, Amy J.; Beswick, R. J.; Cheung, C. C.; Mukai, Koji; Nelson, Thomas

    2014-01-01

    Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10 (sup -4) solar masses of material at velocities exceeding 1,000 kilometers per second.However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at giga-electronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion..At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are gamma-ray emitters.

  2. Orbital motion and mass flow in the interacting binary Be star HR 2142

    Science.gov (United States)

    Peters, G. J.

    1983-01-01

    The discovery of an unusual, periodic, two-component shell phase of short duration in the 'classical' Be star HR2142 (HD41335, MWC133) offered convincing evidence that this object is a mass-transfer binary system. A model based solely on the phase-dependent behavior of the hydrogen shell lines in this 80(d).860 binary was developed by Peters and Polidan (1973) and by Peters (1976). The present investigation is concerned with a refinement to the earlier model, taking into account the utilization of an orbital solution obtained from measurements of the wings of the broad photospheric features observed in the rapidly rotating primary. Velocities and equivalent widths from the sharp 'shell' lines, presumably formed in or near the gas stream, provide additional information on the mass flow in the Balmer-line-formation region.

  3. Spin-orbit precession for eccentric black hole binaries at first order in the mass ratio

    CERN Document Server

    Akcay, Sarp; Dolan, Sam

    2016-01-01

    We consider spin-orbit ("geodetic") precession for a compact binary in strong-field gravity. Specifically, we compute $\\psi$, the ratio of the accumulated spin-precession and orbital angles over one radial period, for a spinning compact body orbiting a non-rotating black hole. We show that $\\psi$ can be computed for eccentric orbits in both the gravitational self-force and post-Newtonian frameworks, and that the results appear to be consistent. We present a post-Newtonian expansion for $\\psi$ at next-to-next-to-leading order, and a Lorenz-gauge gravitational self-force calculation for $\\psi$ at first order in the mass ratio. The latter provides new numerical data in the strong-field regime to inform the Effective One-Body model of the gravitational two-body problem. We conclude that $\\psi$ complements the Detweiler redshift $z$ as a key invariant quantity characterizing eccentric orbits in the gravitational two-body problem.

  4. On the Orbit of Visual Binary ADS 8119 AB ({\\alpha} = 11h18m10s.9 and {\\delta}=+31o31'44".9)

    CERN Document Server

    Siregar, S

    2010-01-01

    Xi UrsaMajoris ({\\xi} Uma) historically is one of the most important double star inconstellation Ursa Major, found by Sir William Herschel on May, 2, 1780 and the first binary successfully determined by using the principle of two body problem in 1828 by Savary. This star consists of two pair wide binary ADS8119 AB; in this case HD 98231(ADS8119 A) as primary and HD98230 (ADS 8119 B) as secondary. We have collected the observational data consist of separation angular ({\\rho}) and position angle ({\\theta}) fromthe observations in 1780 up to 2005 taken from Bosscha Observatory and other Observatories in the world. This paper presents the recent status of orbit binary system ADS 8119. By using Thiele Van den Bos method and empirical formula Strand's Mass-Luminosity relation we have determined the orbit and mass of ADS 8119AB. The result is; Orbital and Physical Element of ADS 8119 AB. Dynamical Elements, Orbit Orientation, Masses-Parallax; P = 60 years, e = 0.426, T = 1935.8, i = 110o9, {\\Omega} = 104o.7, {\\omega...

  5. Dynamical analyses of the companions orbiting eclipsing binaries - I. SW Lacertae

    Science.gov (United States)

    Yuan, Jinzhao; Şenavci, Hakan Volkan

    2014-03-01

    New mid-eclipse times of the short-period eclipsing binary SW Lacertae are reported, and two cyclical variations are found in the corresponding O - C diagram. The proposed light-travel time model is refined. The best fit suggests that two possible circumbinary companions are in a near 3:1 mean-motion resonance with periods of 27.01 and 82.61 yr. Based on the best-fitting solution, we have studied the stabilities of the two companions moving on a series of mutually inclined orbits. The results show that no orbital configurations can survive for >1000 yr. Then, non-Keplerian corrections to the initial conditions and the more distant K-dwarf companion discovered by Ruciński, Pribulla & van Kerkwijk, moving on assumed circular orbits with wide ranges of orbital inclinations, are considered in our numerical simulations. The outcome similarly reveals that the whole system is yet short-term unstable. Perhaps, one or both cyclical variations in the mid-eclipse times are attributed to irregular mass exchange and/or magnetic cycles in the magnetically active W UMa system. Despite this, the instability of the system may also arise from the large uncertainties in orbital parameters. So, secular observations of this target are needed to determine the eccentricity of the outmost companion and the orbital period of the middle companion with much higher precision. Our results suggest that, if the two inner companions do exist, they should be on mutually inclined orbits of >100°, with the minimum masses of 0.62 and 1.94 M⊙ for the innermost and middle components, respectively. Our work demonstrates that it is important and necessary to perform dynamical analyses before a discovery of two or more circumbinary companions is announced.

  6. Evolution of low-mass close binaries with orbital angular momentum losses

    Energy Technology Data Exchange (ETDEWEB)

    Tutukov, A.V.; Ergma, E.V.; Fedorova, A.V.; Yungelson, L.R.

    1986-07-01

    The evolution of secondary components in close binary systems with compact primary components is calculated with allowance for orbital angular momentum loss by means of a magnetic stellar wind and gravitational wave radiation. Stars with chemical compositions corresponding to disk and bulge objects are considered. The influence of induced stellar wind on the evolution of secondary components is investigated. The results of the calculations make it possible to explain the period distribution of cataclysmic variables and matter transfer rates observed in them and in low-mass x-ray sources.

  7. THE SPECTROSCOPIC ORBITS OF FIVE SOLAR-TYPE, SINGLE-LINED BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Fekel, Francis C.; Rajabi, Samira; Muterspaugh, Matthew W.; Williamson, Michael H., E-mail: fekel@evans.tsuniv.edu, E-mail: samira@coe.tsuniv.edu, E-mail: matthew1@coe.tsuniv.edu, E-mail: michael.h.williamson@gmail.com [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Boulevard, Box 9501, Nashville, TN 37209 (United States)

    2013-04-15

    We have determined spectroscopic orbits for five single-lined spectroscopic binaries, HD 100167, HD 135991, HD 140667, HD 158222, HD 217924. Their periods range from 60.6 to 2403 days and the eccentricities from 0.20 to 0.84. Our spectral classes for the stars confirm that they are of solar type, F9-G5, and all are dwarfs. Their [Fe/H] abundances, determined spectroscopically, are close to the solar value and on average are 0.12 greater than abundances from a photometric calibration. Four of the five stars are rotating faster than their predicted pseudosynchronous rotational velocities.

  8. Next-to-leading tail-induced spin–orbit effects in the gravitational radiation flux of compact binaries

    International Nuclear Information System (INIS)

    The imprint of nonlinearities in the propagation of gravitational waves—the tail effect—is responsible for new spin contributions to the energy flux and orbital phasing of spinning black hole binaries. The spin–orbit (linear in spin) contribution to this effect is currently known at leading post-Newtonian (PN) order, namely 3PN for maximally spinning black holes on quasi-circular orbits. In the present work, we generalize these tail-originated spin–orbit terms to the next-to-leading 4PN order. This requires in particular extending previous results on the dynamical evolution of precessing compact binaries. We show that the tails represent the only spin–orbit terms at that order for quasi-circular orbits, and we find perfect agreement with the known result for a test particle around a Kerr black hole, computed by perturbation theory. The BH-horizon absorption terms have to be added to the PN result computed here. Our work completes the knowledge of the spin–orbit effects to the phasing of compact binaries up to the 4PN order, and will allow the building of more faithful PN templates for the inspiral phase of black hole binaries, improving the capabilities of ground-based and space-based gravitational wave detectors. (paper)

  9. Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos II. Preliminary orbits for six astrometric binaries

    CERN Document Server

    Gontcharov, G A

    2016-01-01

    Based on a direct combination of the Hipparcos data with astrometric ground-based observational catalogues having epochs between 1938 and 1999 the preliminary orbits and component masses are calculated for 6 binaries with no previous orbit calculation: $\\iota$~Vir (HIP~69701) with period of 55 years, photocentric semi-major axis of 200 mas, relative semi-major axis of 830 mas and a dwarf secondary of 0.6 solar masses; $\\gamma$~UMa (HIP~58001) -- 20.5 years, 90 mas, 460 mas and a dwarf secondary of 0.8 solar masses; $\\kappa$~Del (HIP~101916) -- 45 years, 100 mas, 520 mas and a dwarf secondary of 0.4 solar masses; 20~Oph (HIP~82369) -- 35.5 years, 140 mas, 460 mas and a dwarf secondary of 0.8 solar masses; $\\mu$~Ser (HIP~77516) -- 36 years, 110 mas, 350 mas and a secondary of 2.3 solar masses; as well as a possible new component of Mizar~A ($\\zeta$~UMa, HIP~65378) -- 36.5 years, 180 mas, 780 mas, 1.5 solar masses. The latter may be a pair of dwarfs.

  10. Highest Occupied Molecular Orbital of Cyclopentanone by Binary (e, 2e) Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-Feng; NING Chuan-Gang; DENG Jing-Kang; REN Xue-Guang; SU Guo-Lin; YANG Tie-Cheng; HUANG Yan-Ru

    2006-01-01

    @@ We report the first measurements of the momentum profiles of highest occupied molecular orbital (HOMO) and the complete valence shell binding energy spectra of cyclopentanone with impact energies of 600 and 1200 eV by a binary (e, 2e) spectrometer. The experimental momentum profiles of the HOMO orbital are compared with the theoretical momentum distribution calculated using the Hartree-Fock and density functional theory methods with various basis sets. However, none of these calculations gives a completely satisfactory description of the momentum distributions of the HOMO 7b2. The inadequacy of the calculations could result in the intensity difference of the second maximum at p ~l.2a.u. between the experiment and the theory. The discrepancy between experimental and theoretical data in the low-momentum region is explained with the distorted wave effect.

  11. First visual orbit for the prototypical colliding-wind binary WR 140

    CERN Document Server

    Monnier, J D; Pedretti, E; Millan-Gabet, R; Berger, J P; Traub, W; Schloerb, F P; Brummelaar, T ten; McAlister, H; Ridgway, S; Sturmann, L; Sturmann, J; Turner, N; Baron, F; Kraus, S; Tannirkulam, A; Williams, P M

    2011-01-01

    Wolf-Rayet stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample. Here we report the first visual orbit for WR 140(=HD193793), a WC7+O5 binary system known for its periodic dust production episodes triggered by intense colliding winds near periastron passage. The IOTA and CHARA interferometers resolved the pair of stars in each year from 2003--2009, covering most of the highly-eccentric, 7.9 year orbit. Combining our results with the recent improved double-line spectroscopic orbit of Fahed et al. (2011), we find the WR 140 system is located at a distance of 1.67 +/- 0.03 kpc, composed of a WR star with M_WR = 14.9 +/- 0.5 Msun and an O star with M_O = 35.9 +/- 1.3 Msun. Our precision orbit yields key parameters with uncertainties times 6 smaller than previous work and paves the way for detailed modeling of the system. Our newly measured ...

  12. Photoelectric Radial Velocities, Paper XVIII Spectroscopic Orbits for Another 52 Binaries in the Hyades Field

    Indian Academy of Sciences (India)

    R. F. Griffin

    2012-03-01

    Spectroscopic orbits are presented for 52 stars in the Hyades field, of which 41 prove to be actual members of the Hyades (with some reservations in two cases). Most of the stars concerned have not had orbits published for them previously. Three of them are of higher multiplicity. The already-known double-lined eclipsing system van Bueren 22 is demonstrated to be a triple system, as was obliquely announced 25 years ago; its `outer’ orbit, which has a period of about 8 years, is now determined. Van Bueren 75 is already known to be triple, but here the visual secondary is shown to be the (single-lined) spectroscopic sub-system, and an independent spectroscopic solution is given for the 40-year orbit of what has hitherto been regarded as the `visual’ pair. Van Bueren 102, for which a close visual companion was discovered comparatively recently, is a single-lined binary whose -velocity has shown a steady drift over at least the last 30 (probably 50) years. Three stars, vB 39, 50 and 59, have notably high eccentricities of 0.85, 0.98 and 0.94, respectively; they have quite long periods (especially vB 50, which is over 100 years), and every one of them contrived to pass the whole of its recent periastron passage (about 180° of true anomaly) between seasons, at the time of year when the Hyades are unobservable!

  13. FIRST VISUAL ORBIT FOR THE PROTOTYPICAL COLLIDING-WIND BINARY WR 140

    International Nuclear Information System (INIS)

    Wolf-Rayet (WR) stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample. Here we report the first visual orbit for WR 140 (= HD193793), a WC7+O5 binary system known for its periodic dust production episodes triggered by intense colliding winds near periastron passage. The Infrared-Optical Telescope Array and Center for High Angular Resolution Astronomy interferometers resolved the pair of stars in each year from 2003 to 2009, covering most of the highly eccentric, 7.9 year orbit. Combining our results with the recently improved double-line spectroscopic orbit of Fahed et al., we find the WR 140 system is located at a distance of 1.67 ± 0.03 kpc, composed of a WR star with MWR = 14.9 ± 0.5 M☉ and an O star with MO = 35.9 ± 1.3 M☉. Our precision orbit yields key parameters with uncertainties ∼6× smaller than previous work and paves the way for detailed modeling of the system. Our newly measured flux ratios at the near-infrared H and Ks bands allow a spectral energy distribution decomposition and analysis of the component evolutionary states.

  14. On the Orbit of Visual Binary WDS 01158-6853 I-27CD (SAO248342)

    CERN Document Server

    Siregar, S

    2010-01-01

    WDS 01158-6853 I-27CD=SA0 248342 has the proper motion +404. in right ascension and 105. in declination. Magnitude of each star is 7.84 for primary and 8.44 for secondary, separated by 320. from the quadruple system Kappa Tuc=LDS 42 = HJ 3423 AB. The visual binary star of WDS 01158-6853 I-27CD is historically one of the most important double star in constellation Tucana. We have collected the observational data consisting of separation angular ({\\rho}) and position angle ({\\theta}) from the observations of 1897 up to 2001 taken at the Bosscha Observatory and other Observatories in the world. This study presents the recent status of orbit binary system WDS 01158-6853 I-27CD. By using Thiele Van den Bos method and empirical formula of Strand's Mass-Luminosity relation we have determined the orbit and mass of WDS 01158-6853 I-27CD. The results are; P=85.288 years, e=0.053, T =1911.23, i=27.93, {\\Omega}=52.83, {\\omega}=10.73, M1=0.7 Mo, M2=0.5 Mo, p=0".0589

  15. Orbital evolution of mass-transferring eccentric binary systems. II. Secular Evolution

    CERN Document Server

    Dosopoulou, Fani

    2016-01-01

    Finite eccentricities in mass-transferring eccentric binary systems can be explained taking into account mass-loss and mass-transfer processes that often occur in these systems. These processes can be treated as perturbations to the general two-body problem. The time-evolution equations for the semi-major axis and the eccentricity derived from perturbative methods are in general phase-dependent. The osculating semi-major axis and eccentricity change over the orbital timescale and they are not easy to implement in binary evolution codes like MESA. However, the secular orbital element evolution equations can be simplified averaging over the rapidly varying true anomalies. In this paper, we derive the secular time-evolution equations for the semi-major axis and the eccentricity for various mass-loss/transfer processes using either the adiabatic approximation or the assumption of delta-function mass-loss/transfer at periastron. We begin with the cases of isotropic and anisotropic wind mass-loss. We continue with ...

  16. Gravitational Radiation Damping and Evolution of the Orbit of Compact Binary Stars (Solution by the Second Perturbation Method)

    Indian Academy of Sciences (India)

    Lin-Sen Li

    2014-06-01

    The influence of the gravitational radiation damping on the evolution of the orbital elements of compact binary stars is examined by using the method of perturbation. The perturbation equations with the true anomaly as an independent variable are given. This effect results in both the secular and periodic variation of the semi-major axis, the eccentricity, the mean longitude at the epoch and the mean longitude. However, the longitude of periastron exhibits no secular variation, but only periodic variation. The effect of secular variation of the orbit would lead to collapse of the system of binary stars. The deduced formulae are applied to the calculation of secular variation of the orbital elements for three compact binary stars: PSR 1913+16, PSR J0737-3039 and M33X-7. The results obtained are discussed.

  17. V346 Centauri: Early-type eclipsing binary with apsidal motion and abrupt change of orbital period

    Science.gov (United States)

    Mayer, Pavel; Harmanec, Petr; Wolf, Marek; Nemravová, Jana; Prša, Andrej; Frémat, Yves; Zejda, Miloslav; Liška, Jiři; Juryšek, Jakub; Hoňková, Kateřina; Mašek, Martin

    2016-06-01

    New physical elements of the early B-type eclipsing binary V346 Cen are derived using the HARPS spectra downloaded from the ESO archive and also numerous photometric observations from various sources. A model of the observed times of primary and secondary minima that fits them best is a combination of the apsidal motion and an abrupt decrease in the orbital period from 6.^d322123 to 6.^d321843 (shortening by 24 s), which occurred somewhere around JD 2 439 000. Assumption of a secularly decreasing orbital period provides a significantly worse fit. Local times of minima and the final solution of the light curve were obtained with the program PHOEBE. Radial velocities of both binary components, free of line blending, were derived via 2D cross-correlation with a program built on the principles of the program TODCOR. The oxygen lines in the secondary spectra are weaker than those in the model spectra of solar chemical composition. Using the component spectra disentangled with the program KOREL, we find that both components rotate considerably faster than would correspond to the synchronization at periastron. The apside rotation known from earlier studies is confirmed and compared to the theoretical value. Based on observations made with the ESO telescopes at the La Silla Paranal Observatory under programmes ID 083.D-0040(A), 085.C-0614(A), and 178.D-0361(B).Tables A.2-A.6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A129

  18. The ARAUCARIA project. OGLE-LMC-CEP-1718: An exotic eclipsing binary system composed of two classical overtone cepheids in a 413 day orbit

    Energy Technology Data Exchange (ETDEWEB)

    Gieren, Wolfgang; Pilecki, Bogumił; Pietrzyński, Grzegorz; Graczyk, Dariusz; Gallenne, Alexandre, E-mail: wgieren@astro-udec.cl, E-mail: pietrzyn@astrouw.edu.pl, E-mail: darek@astro-udec.cl, E-mail: dgallenne@astro-udec.cl, E-mail: bpilecki@astro-udec.cl [Departamento de Astronomia, Universidad de Concepción, Casilla 160-C, Concepción (Chile); and others

    2014-05-10

    We have obtained extensive high-quality spectroscopic observations of the OGLE-LMC-CEP-1718 eclipsing binary system in the Large Magellanic Cloud that Soszyński et al. had identified as a candidate system for containing two classical Cepheids in orbit. Our spectroscopic data clearly demonstrate binary motion of the Cepheids in a 413 day eccentric orbit, rendering this eclipsing binary system the first ever known to consist of 2 classical Cepheid variables. After disentangling the four different radial velocity variations in the system, we present the orbital solution and the individual pulsational radial velocity curves of the Cepheids. We show that both Cepheids are extremely likely to be first overtone pulsators and determine their respective dynamical masses, which turn out to be equal to within 1.5%. Since the secondary eclipse is not observed in the orbital light curve, we cannot derive the individual radii of the Cepheids, but the sum of their radii derived from the photometry is consistent with overtone pulsation for both variables. The existence of two equal-mass Cepheids in a binary system having different pulsation periods (1.96 and 2.48 days, respectively) may pose an interesting challenge to stellar evolution and pulsation theories, and a more detailed study of this system using additional data sets should yield deeper insight about the physics of stellar evolution of Cepheid variables. Future analysis of the system using additional near-infrared photometry might also lead to a better understanding of the systematic uncertainties in current Baade-Wesselink techniques of distance determinations to Cepheid variables.

  19. Pulsar Timing Residuals Induced by Gravitational Waves from Single Non-evolving Supermassive Black Hole Binaries with Elliptical Orbits

    International Nuclear Information System (INIS)

    The pulsar timing residuals induced by gravitational waves from non-evolving single binary sources with general elliptical orbits are analyzed. For different orbital eccentricities, the timing residuals present different properties. The standard deviations of the timing residuals induced by a fixed gravitational wave source are calculated for different values of the eccentricity. We also analyze the timing residuals of PSR J0437-4715 induced by one of the best known single gravitational wave sources, the supermassive black hole binary in the blazar OJ287

  20. A circumbinary planet in orbit around the short-period white dwarf eclipsing binary RR Cae

    Science.gov (United States)

    Qian, S.-B.; Liu, L.; Zhu, L.-Y.; Dai, Z.-B.; Fernández Lajús, E.; Baume, G. L.

    2012-05-01

    By using six newly determined mid-eclipse times together with those collected from the literature, we have found that the observed minus calculated (O-C) curve of RR Cae shows a cyclic change with a period of 11.9 yr and an amplitude of 14.3 s while it undergoes an upward parabolic variation [revealing a long-term period increase at a rate of ?]. The cyclic change was analysed for the light-travel-time effect that arises from the gravitational influence of a third companion. The mass of the third body was determined to be M3sin i'= 4.2(± 0.4) MJup, suggesting that it is a circumbinary giant planet when its orbital inclination is larger than 17?6. The orbital separation of the circumbinary planet from the central eclipsing binary is about 5.3(± 0.6) au. The period increase is opposite to the changes caused by angular momentum loss via magnetic braking or/and gravitational radiation; and it cannot be explained by the mass transfer between both components because of its detached configuration. These indicate that the observed upward parabolic change is only a part of a long-period (longer than 26.3 yr) cyclic variation, which may reveal the presence of another giant circumbinary planet in a wide orbit.

  1. Binary neutron star merger simulations with different initial orbital frequency and equation of state

    CERN Document Server

    Maione, Francesco; Feo, Alessandra; Löffler, Frank

    2016-01-01

    We present results from three-dimensional general relativistic simulations of binary neutron star coalescences and mergers using public codes. We considered equal mass models where the baryon mass of the two Neutron Stars (NS) is $1.4M_{\\odot}$, described by four different equations of state (EOS) for the cold nuclear matter (APR4, SLy, H4, and MS1; all parametrized as piecewise polytropes). We started the simulations from four different initial interbinary distances ($40, 44.3, 50$, and $60$ km), including up to the last 16 orbits before merger. That allows to show the effects on the gravitational wave phase evolution, radiated energy and angular momentum due to: the use of different EOSs, the orbital eccentricity present in the initial data and the initial separation (in the simulation) between the two stars. Our results show that eccentricity has a major role in the discrepancy between numerical and analytical waveforms until the very last few orbits, where "tidal" effects and missing high-order post-Newto...

  2. Orbital motions and light curves of young binaries XZ Tau and VY Tau

    CERN Document Server

    Dodin, A V; Zharova, A V; Lamzin, S A; Malogolovets, E V; Roe, J M

    2015-01-01

    The results of our speckle interferometric observations of young binaries VY Tau and XZ Tau are presented. For the first time, we found a relative displacement of VY Tau components as well as a preliminary orbit for XZ Tau. It appeared that the orbit is appreciably non-circular and is inclined by $i \\lesssim 47^o$ from the plane of the sky. It means that the rotation axis of XZ Tau A and the axis of its jet are significantly non-perpendicular to the orbital plane. We found that the average brightness of XZ Tau had been increasing from the beginning of the last century up to the mid-thirties and then it decreased by $\\Delta B > 2$ mag. The maximal brightness has been reached significantly later on the time of periastron passage. The total brightness of XZ Tau's components varied in a non-regular way from 1970 to 1985 when eruptions of hot gas from XZ Tau A presumably had occurred. In the early nineties the variations became regular following which a chaotic variability had renewed. We also report that a flare ...

  3. The Evolution of Planet-Disk Systems That Are Mildly Inclined to the Orbit of a Binary Companion

    CERN Document Server

    Lubow, Stephen H

    2015-01-01

    We determine the evolution of a giant planet-disk system that orbits a member of a binary star system and is mildly inclined with respect to the binary orbital plane. The planet orbit and disk are initially mutually coplanar. We analyze the evolution of the planet and the disk by analytic means and hydrodynamic simulations. We generally find that the planet and the disk do not remain coplanar unless the disk mass is very large or the gap that separates the planet from the disk is very small. The relative planet-disk tilt undergoes secular oscillations whose initial amplitudes are typically of order the initial disk tilt relative to the binary orbital plane for disk masses ~1% of the binary mass or less. The effects of a secular resonance and the disk tilt decay enhance the planet-disk misalignment. The secular resonance plays an important role for disk masses greater than the planet mass. At later times, the accretion of disk gas by the planet causes its orbit to evolve towards alignment, if the disk mass is ...

  4. Wind-wind collision in the Carinae binary system II: Constrains to the binary orbital parameters from radio emission near periastron passage

    OpenAIRE

    Abraham, Z.; Falceta-Goncalves, D.; Dominici, T. P.; A. Caproni; Jatenco-Pereira, V.

    2005-01-01

    In this paper we use the 7 mm and 1.3 mm light curves obtained during the 2003.5 low excitation phase of the eta Carinae system to constrain the possible parameters of the binary orbit. To do that we assumed that the mm wave emission is produced in a dense disk surrounding the binary system; during the low excitation phase, which occurs close to periastron, the number of ionizing photons decreases, producing the dip in the radio emission. On the other hand, due to the large eccentricity, the ...

  5. Next-to-next-to-leading order spin–orbit effects in the gravitational wave flux and orbital phasing of compact binaries

    International Nuclear Information System (INIS)

    We compute the next-to-next-to-leading order spin–orbit contributions in the total energy flux emitted in gravitational waves by compact binary systems. Such contributions correspond to the post-Newtonian order 3.5PN for maximally spinning compact objects. Continuing our recent work on the next-to-next-to-leading spin–orbit terms at the 3.5PN order in the equations of motion, we obtain the spin–orbit terms in the multipole moments of the compact binary system up to the same order within the multipolar post-Newtonian wave generation formalism. Our calculation of the multipole moments is valid for general orbits and in an arbitrary frame, the moments are then reduced to the center-of-mass frame and the resulting energy flux is specialized to quasi-circular orbits. The test-mass limit of our final result for the flux agrees with the already known Kerr black hole perturbation limit. Furthermore, the various multipole moments of the compact binary reduce in the one-body case to those of a single-boosted Kerr black hole. We briefly discuss the implications of our result for the gravitational wave flux in terms of the binary’s phase evolution, and address its importance for the future detection and parameter estimation of signals in gravitational wave detectors. (paper)

  6. The Effects of High-Velocity Supernova Kicks on the Orbital Properties and Sky Distributions of Neutron Star Binaries

    OpenAIRE

    Brandt, W. N.; Podsiadlowski, Ph.

    1994-01-01

    We systematically investigate the effects of high supernova kick velocities on the orbital parameters of post-supernova neutron-star binaries. Using Monte- Carlo simulations, we determine the post-supernova distributions of orbital parameters for progeneitors of HMXBs and LMXBs. With the recent distribution of pulsar birth velocities by Lyne & Lorimer (1994), only about 27% of massive systems remain bound after the supernova, of which about 26% immediately experience dynamical mass transfer a...

  7. Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

    CERN Document Server

    Madura, Thomas I; Owocki, Stanley P; Groh, Jose H; Okazaki, Atsuo T; Russell, Christopher M P

    2011-01-01

    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA {\\theta} that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38 degrees, and the temporal variations in emission seen at negative slit PAs, the binary ...

  8. BLACK HOLE SPIN-ORBIT MISALIGNMENT IN GALACTIC X-RAY BINARIES

    International Nuclear Information System (INIS)

    In black hole (BH) X-ray binaries (XRBs), a misalignment between the spin axis of the BH and the orbital angular momentum can occur during the supernova explosion that forms the compact object. In this Letter, we present population synthesis (PS) models of Galactic BH XRBs and study the probability density function of the misalignment angle and its dependence on our model parameters. In our modeling, we also take into account the evolution of the misalignment angle due to accretion of material onto the BH during the XRB phase. The major factor that sets the misalignment angle for XRBs is the natal kick that the BH may receive at its formation. However, large kicks tend to disrupt binaries, while small kicks allow the formation of XRBs and naturally select systems with small misalignment angles. Our calculations predict that the majority (>67%) of Galactic field BH XRBs have rather small (∼0) misalignment angles, while some systems may reach misalignment angles as high as ∼900 and even higher. These results are robust among all PS models. The assumption of small misalignment angles is extensively used to observationally estimate BH spin magnitudes, and for the first time we are able to confirm this assumption using detailed PS calculations.

  9. Initial Data for Binary Neutron Stars with Arbitrary Spin and Orbital Eccentricity

    Science.gov (United States)

    Tsatsin, Petr; Marronetti, Pedro

    2013-04-01

    The starting point of any general relativistic numerical simulation is a solution of the Hamiltonian and momentum constraint. One characteristic of the Binary Neutron Star (BNS) initial data problem is that, unlike the case of binary black holes, there are no formalisms that permit the construction of initial data for stars with arbitrary spins. For many years, the only options available have been systems either with irrotational or corotating fluid. Ten years ago, Marronetti & Shapiro (2003) introduced an approximation that would produce such arbitrarily spinning systems. More recently, Tichy (2012) presented a new formulation to do the same. However, all these data sets are bound to have a non-zero eccentricity that results from the fact the stars' velocity have initial null radial components. We present here a new approximation for BNS initial data for systems that possess arbitrary spins and arbitrary radial and tangential velocity components. The latter allows for the construction of data sets with arbitrary orbital eccentricity. Through the fine-tuning of the radial component, we were able to reduce the eccentricity by a factor of several compared to that of standard helical symmetry data sets such as those currently used in the scientific community.

  10. Orbit Display's Use of the Physics Application Framework

    International Nuclear Information System (INIS)

    At the SLAC National Accelerator Laboratory (SLAC) the Controls Department (CD) is developing a physics application framework based on the Java(tm) programming language developed by Sun Microsystems. This paper will discuss the first application developed using this approach: a new Orbit Display. The software is being developed by several individuals in reusable Java packages. It relies on the Experimental Physics and Industrial Control System (EPICS) toolkit for data collection and XAL - A Java based Hierarchy for Application Programming for model parameters. The Orbit Display tracks and displays electron paths through the Linac Coherent Light Source (LCLS) in both a graphical, beam line plot, and tabular format. It contains many features that may be unique to SLAC and is meant to be used both in the control room and by individuals in their offices or at home. Unique features include BSA Beam Synchronous Acquisition (BSA), Orbit Fitting, and Buffered Acquisition.

  11. An Analytic Method to determine Habitable Zones for S-Type Planetary Orbits in Binary Star Systems

    CERN Document Server

    Eggl, Siegfried; Georgakarakos, Nikolaos; Gyergyovits, Markus; Funk, Barbara

    2012-01-01

    With more and more extrasolar planets discovered in and around binary star systems, questions concerning the determination of the classical Habitable Zone arise. Do the radiative and gravitational perturbations of the second star influence the extent of the Habitable Zone significantly, or is it sufficient to consider the host-star only? In this article we investigate the implications of stellar companions with different spectral types on the insolation a terrestrial planet receives orbiting a Sun-like primary. We present time independent analytical estimates and compare these to insolation statistics gained via high precision numerical orbit calculations. Results suggest a strong dependence of permanent habitability on the binary's eccentricity, as well as a possible extension of Habitable Zones towards the secondary in close binary systems.

  12. AN ANALYTIC METHOD TO DETERMINE HABITABLE ZONES FOR S-TYPE PLANETARY ORBITS IN BINARY STAR SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Eggl, Siegfried; Pilat-Lohinger, Elke; Gyergyovits, Markus; Funk, Barbara [Institute for Astronomy, University of Vienna, Tuerkenschanzstr. 17, A-1180 Vienna (Austria); Georgakarakos, Nikolaos, E-mail: siegfried.eggl@univie.ac.at, E-mail: elke.pilat-lohinger@univie.ac.at [128 V. Olgas str., Thessaloniki 546 45 (Greece)

    2012-06-10

    With more and more extrasolar planets discovered in and around binary star systems, questions concerning the determination of the classical habitable zone have arisen. Do the radiative and gravitational perturbations of the second star influence the extent of the habitable zone significantly, or is it sufficient to consider the host star only? In this article, we investigate the implications of stellar companions with different spectral types on the insolation a terrestrial planet receives orbiting a Sun-like primary. We present time-independent analytical estimates and compare them to insolation statistics gained via high precision numerical orbit calculations. Results suggest a strong dependence of permanent habitability on the binary's eccentricity, as well as a possible extension of habitable zones toward the secondary in close binary systems.

  13. Masses of the components of SB2 binaries observed with Gaia - III. Accurate SB2 orbits for 10 binaries and masses of HIP 87895

    Science.gov (United States)

    Kiefer, F.; Halbwachs, J.-L.; Arenou, F.; Pourbaix, D.; Famaey, B.; Guillout, P.; Lebreton, Y.; Nebot Gómez-Morán, A.; Mazeh, T.; Salomon, J.-B.; Soubiran, C.; Tal-Or, L.

    2016-05-01

    In anticipation of the Gaia astrometric mission, a large sample of spectroscopic binaries has been observed since 2010 with the Spectrographe pour l'Observation des PHénomènes des Intérieurs Stellaires et des Exoplanètes spectrograph at the Haute-Provence Observatory. Our aim is to derive the orbital elements of double-lined spectroscopic binaries (SB2s) with an accuracy sufficient to finally obtain the masses of the components with relative errors as small as 1 per cent when the astrometric measurements of Gaia are taken into account. In this paper, we present the results from five years of observations of 10 SB2 systems with periods ranging from 37 to 881 d. Using the TODMOR algorithm, we computed radial velocities from the spectra, and then derived the orbital elements of these binary systems. The minimum masses of the components are then obtained with an accuracy better than 1.2 per cent for the 10 binaries. Combining the radial velocities with existing interferometric measurements, we derived the masses of the primary and secondary components of HIP 87895 with an accuracy of 0.98 and 1.2 per cent, respectively.

  14. Masses of the components of SB2 binaries observed with Gaia. III. Accurate SB2 orbits for 10 binaries and masses of HIP 87895

    CERN Document Server

    Kiefer, Flavien; Arenou, Frédéric; Pourbaix, Dimitri; Famaey, Benoit; Guillout, Patrick; Lebreton, Yveline; Gómez-Morán, Ada Nebot; Mazeh, Tsevi; Salomon, Jean-Baptiste; Soubiran, Caroline; Tal-Or, Lev

    2016-01-01

    In anticipation of the Gaia astrometric mission, a large sample of spectroscopic binaries has been observed since 2010 with the SOPHIE spectrograph at the Haute--Provence Observatory. Our aim is to derive the orbital elements of double-lined spectroscopic binaries (SB2s) with an accuracy sufficient to finally obtain the masses of the components with relative errors as small as 1 % when the astrometric measurements of Gaia are taken into account. In this paper we present the results from five years of observations of 10 SB2 systems with periods ranging from 37 to 881 days. Using the TODMOR algorithm we computed radial velocities from the spectra, and then derived the orbital elements of these binary systems. The minimum masses of the components are then obtained with an accuracy better than 1.2 % for the ten binaries. Combining the radial velocities with existing interferometric measurements, we derived the masses of the primary and secondary components of HIP 87895 with an accuracy of 0.98 % and 1.2 % respect...

  15. An orbital period investigation of the Algol-type eclipsing binary VW Hydrae

    Institute of Scientific and Technical Information of China (English)

    Jia Zhang; Sheng-Bang Qian; Boonrucksar Soonthornthum

    2009-01-01

    Orbital period variations of the Algol-type eclipsing binary, VW Hydrae, are analyzed based on one newly determined eclipse time and the other times of light minima collected from the literature. It is discovered that the orbital period shows a continuous increase at a rate of dP/dt = +6.34×10-7 d yr-1 while it undergoes a cyclic change with an amplitude of 0.0639 d and a period of 51.5 yr. After the long-term period increase and the large-amphtude period oscillation were subtracted from the O-C curve, the residuals of the photoelectric and CCD data indicate a small-amplitude cyclic variation with a period of 8.75 yr and a small amplitude of 0.0048d. The continuous period increase indicates a conservative mass transfer at a rate of dM2/dt = 7.89×10-8 M⊙ yr-1 from the secondary to the primary. The period increase may be caused by a combination of the mass transfer from the secondary to the primary and the angular momentum transfer from the binary system to the circumbinary disk. The two cyclic period oscillations can be explained by light-travel time effects via the presence of additional bodies. The small-amplitude periodic change indicates the existence of a less massive component with mass M3 > 0.53 M⊙, while the large-amplitude one is caused by the presence of a more massive component with mass M4 > 2.84 M⊙. The ultraviolet source in the system reported by Kviz & Rufener (1987) may be one of the additional components, and it is possible that the more massive one may be an unseen neutron star or black hole. The rapid period increase and the possibility of the presence of two additional components in the binary make it a very interesting system to study. New photometric and high-resolution spectroscopic observations and a detailed investigation of those data are required in the future.

  16. Asteroseismic probing of internal rotation in hot B subdwarf stars: Testing spin-orbit synchronism in two close binary systems

    International Nuclear Information System (INIS)

    We present internal rotation profiles derived from asteroseismology for the hot pulsating B subdwarf stars PG 1336-018 and Feige 48. These two pulsators are primaries of close binary systems of known orbital period and, therefore, provide laboratories to test, for the first time, spin-orbit synchronization as a function of depth. We show that PG 1336-018 and Feige 48 clearly rotate as solid bodies with periods equal to their orbital periods from the surface down to at least ∼ 0.5 and ∼ 0.3 their radius, respectively. Deep tidal locking has therefore developed within the relatively short lifetime of these stars (∼ 108 yr).

  17. Eccentric orbital motion of compact binaries with aligned spins and angular momentum under higher order spin coupling

    CERN Document Server

    Tessmer, Manuel; Schaefer, Gerhard

    2010-01-01

    A quasi-Keplerian parameterisation for the solutions of second post-Newtonian (PN) accurate equations of motion for spinning compact binaries is obtained including leading order spin-spin and next-to-leading order spin-orbit interactions. Rotational deformation of the compact objects is incorporated. For arbitrary mass ratios the spin orientations are taken to be parallel or anti-parallel to the orbital angular momentum vector. The emitted gravitational wave forms are given in analytic form up to 2PN point particle, 1.5PN spin orbit and 1PN spin-spin contributions, where the spins are counted of 0PN order.

  18. Orbital Period Determinations for Four SMC Be/X-ray Binaries

    CERN Document Server

    Schurch, M P E; McBride, V A; Townsend, L J; Udalski, A; Haberl, F; Corbet, R H D

    2010-01-01

    We present an optical and X-ray study of four Be/X-ray binaries located in the Small Magellanic Cloud (SMC). OGLE I-band data of up to 11 years of semi-continuous monitoring has been analysed for SMC X-2, SXP172 and SXP202B, providing both a measurement of the orbital period (Porb = 18.62, 68.90, and 229.9 days for the pulsars respectively) and a detailed optical orbital profile for each pulsar. For SXP172 this has allowed a direct comparison of the optical and X-ray emission seen through regular RXTE monitoring, revealing that the X-ray outbursts precede the optical by around 7 days. Recent X-ray studies by XMM-Newton have identified a new source in the vicinity of SXP15.3 raising doubt on the identification of the optical counterpart to this X-ray pulsar. Here we present a discussion of the observations that led to the proposal of the original counterpart and a detailed optical analysis of the counterpart to the new X-ray source, identifying a 21.7 d periodicity in the OGLE I-band data. The optical characte...

  19. V474 Car: A Rare Halo RS CVn Binary in Retrograde Galactic Orbit

    CERN Document Server

    Bubar, Eric J; Jensen, Eric L N; Walter, Frederick M

    2011-01-01

    We report the discovery that the star V474 Car is an extremely active, high velocity halo RS CVn system. The star was originally identified as a possible pre-main sequence star in Carina, given its enhanced stellar activity, rapid rotation (10.3 days), enhanced Li, and absolute magnitude that places it above the main sequence. However, its extreme radial velocity (264 km s$^{-1}$) suggested that this system was unlike any previously known pre-MS system. Our detailed spectroscopic analysis of echelle spectra taken with the CTIO 4-m finds that V474 Car is both a spectroscopic binary with orbital period similar to the photometric rotation period, and metal poor ([Fe/H] $\\simeq -$0.99). The star's Galactic orbit is extremely eccentric (e $\\simeq$ 0.93) with perigalacticon of only $\\sim$0.3 kpc of the Galactic center - and its eccentricity and smallness of its perigalacticon are only surpassed by $\\sim$0.05%, of local F/G-type field stars. The observed characteristics are consistent with V474 Car being a high velo...

  20. Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir

    CERN Document Server

    Qian, S -B; Dai, Z -B; Lajús, E Fernández; Xiang, F -Y; He, J -J

    2011-01-01

    We report here the tentative discovery of a Jovian planet in orbit around the rapidly pulsating subdwarf B-type (sdB-type) eclipsing binary NY Vir. By using new determined eclipse times together with those collected from the literature, we detect that the observed-calculated (O-C) curve of NY Vir shows a small-amplitude cyclic variation with a period of 7.9\\,years and a semiamplitude of 6.1\\,s, while it undergoes a downward parabolic change (revealing a period decrease at a rate of $\\dot{P}=-9.2\\times{10^{-12}}$). The periodic variation was analyzed for the light-travel time effect via the presence of a third body. The mass of the tertiary companion was determined to be $M_3\\sin{i^{\\prime}}=2.3(\\pm0.3)$\\,$M_{Jupiter}$ when a total mass of 0.60\\,$M_{\\odot}$ for NY Vir is adopted. This suggests that it is most probably a giant circumbinary planet orbiting NY Vir at a distance of about 3.3 astronomical units (AU). Since the rate of period decrease can not be explained by true angular momentum loss caused by grav...

  1. CIRCUMBINARY PLANETS ORBITING THE RAPIDLY PULSATING SUBDWARF B-TYPE BINARY NY Vir

    International Nuclear Information System (INIS)

    We report here the tentative discovery of a Jovian planet in orbit around the rapidly pulsating subdwarf B-type (sdB-type) eclipsing binary NY Vir. By using newly determined eclipse times together with those collected from the literature, we detect that the observed-calculated (O – C) curve of NY Vir shows a small-amplitude cyclic variation with a period of 7.9 yr and a semiamplitude of 6.1 s, while it undergoes a downward parabolic change (revealing a period decrease at a rate of P-dot = -9.2 x 10-12). The periodic variation was analyzed for the light-travel-time effect via the presence of a third body. The mass of the tertiary companion was determined to be M3sin i' = 2.3(± 0.3)MJupiter when a total mass of 0.60 M☉ for NY Vir is adopted. This suggests that it is most probably a giant circumbinary planet orbiting NY Vir at a distance of about 3.3 astronomical units (AU). Since the rate of period decrease cannot be explained by true angular momentum loss caused by gravitational radiation or/and magnetic braking, the observed downward parabolic change in the O – C diagram may be only a part of a long-period (longer than 15 years) cyclic variation, which may reveal the presence of another Jovian planet (∼2.5 MJupiter) in the system.

  2. The binary near-Earth asteroid (175706) 1996 FG3 - An observational constraint on its orbital stability

    CERN Document Server

    Scheirich, P; Jacobson, S A; Ďurech, J; Kušnirák, P; Hornoch, K; Mottola, S; Mommert, M; Hellmich, S; Pray, D; Polishook, D; Krugly, Yu N; Inasaridze, R Ya; Kvaratskhelia, O I; Ayvazian, V; Slyusarev, I; Pittichová, J; Jehin, E; Manfroid, J; Gillon, M; Galád, A; Pollock, J; Licandro, J; Alí-Lagoa, V; Brinsfield, J; Molotov, I E

    2014-01-01

    Using our photometric observations taken between April 1996 and January 2013 and other published data, we derive properties of the binary near-Earth asteroid (175706) 1996 FG3 including new measurements constraining evolution of the mutual orbit with potential consequences for the entire binary asteroid population. We also refined previously determined values of parameters of both components, making 1996 FG3 one of the most well understood binary asteroid systems. We determined the orbital vector with a substantially greater accuracy than before and we also placed constraints on a stability of the orbit. Specifically, the ecliptic longitude and latitude of the orbital pole are 266{\\deg} and -83{\\deg}, respectively, with the mean radius of the uncertainty area of 4{\\deg}, and the orbital period is 16.1508 +\\- 0.0002 h (all uncertainties correspond to 3sigma). We looked for a quadratic drift of the mean anomaly of the satellite and obtained a value of 0.04 +\\- 0.20 deg/yr^2, i.e., consistent with zero. The drif...

  3. New precision orbits of bright double-lined spectroscopic binaries. IX. HD 54371, HR 2692, and 16 ursa majoris

    Energy Technology Data Exchange (ETDEWEB)

    Fekel, Francis C.; Williamson, Michael H.; Muterspaugh, Matthew W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Boulevard, Box 9501, Nashville, TN 37209 (United States); Pourbaix, Dimitri [FNRS Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP 226, B-1050 Bruxelles (Belgium); Willmarth, Daryl [Kitt Peak National Obsevatory, P.O. Box 26732, Tucson, AZ 85726-6732 (United States); Tomkin, Jocelyn, E-mail: fekel@evans.tsuniv.edu, E-mail: michael.h.williamson@gmail.com, E-mail: matthew1@coe.tsuniv.edu, E-mail: pourbaix@astro.ulb.ac.be, E-mail: dwillmarth@noao.edu [Astronomy Department and McDonald Observatory, University of Texas, Austin, TX 78712 (United States)

    2015-02-01

    With extensive sets of new radial velocities we have determined orbital elements for three previously known spectroscopic binaries, HD 54371, HR 2692, and 16 UMa. All three systems have had the lines of their secondaries detected for the first time. The orbital periods range from 16.24 to 113.23 days, and the three binaries have modestly or moderately eccentric orbits. The secondary to primary mass ratios range from 0.50 to 0.64. The orbital dimensions (a{sub 1} sin i and a{sub 2} sin i) and minimum masses (m{sub 1} sin{sup 3} i and m{sub 2} sin{sup 3} i) of the binary components all have accuracies of ⩽1%. With our spectroscopic results and the Hipparcos data, we also have determined astrometric orbits for two of the three systems, HR 2692 and 16 UMa. The primaries of HD 54371 and 16 UMa are solar-type stars, and their secondaries are likely K or M dwarfs. The primary of HR 2692 is a late-type subgiant and its secondary is a G or K dwarf. The primaries of both HR 2692 and 16 UMa may be pseudosynchronously rotating, while that of HD 54371 is rotating faster than its pseudosynchronous velocity.

  4. Orbit of the OJ287 black hole binary as determined from the General Relativity centenary flare

    Science.gov (United States)

    Valtonen, Mauri; Gopakumar, Achamveedu; Mikkola, Seppo; Zola, Staszek; Ciprini, Stefano; Matsumoto, Katsura; Sadakane, Kozo; Kidger, Mark; Gazeas, Kosmas; Nilsson, Kari; Berdyugin, Andrei; Piirola, Vilppu; Jermak, Helen; Baliyan, Kiran; Hudec, Rene; Reichart, Daniel

    2016-05-01

    OJ287 goes through large optical flares twice each 12 years. The times of these flares have been predicted successfully now 5 times using a black hole binary model. In this model a secondary black hole goes around a primary black hole, impacting the accretion disk of the latter twice per orbital period, creating a thermal flare. Together with 6 flares from the historical data base, the set of flare timings determines uniquely the 7 parameters of the model: the two masses, the primary spin, the major axis, eccentricity and the phase of the orbit, plus a time delay parameter that gives the extent of time between accretion disk impacts and the related optical flares. Based on observations by the OJ287-15/16 Collaboration, OJ287 went into the phase of rapid flux rise on November 25, on the centenary of Einstein’s General Relativity, and peaked on December 5. At that time OJ287 was the brightest in over 30 years in optical wavelengths. The flare was of low polarization, and did not extend beyond the optical/UV region of the spectrum. On top of the main flare there were a number of small flares; their excess brightness correlates well with the simultaneous X-ray data. With these properties the main flare qualifies as the marker of the orbit of the secondary going around the primary black hole. Since the orbit solution is strongly over-determined, its parameters are known very accurately, at better than one percent level for the masses and the spin. The next flare is predicted to peak on July 28, 2019.Detailed monitoring of this event should allow us to test, for the first time, the celebrated black hole no-hair theorem for a massive black hole at the 10% level. The present data is consistent with the theorem only at a 30% level. The main difficulty in observing OJ287 from Earth at our predicted epoch is its closeness to the sun. Therefore, it is desirable to monitor OJ287 from a space-based telescope not in the vicinity of Earth. Unfortunately, this unique opportunity

  5. Massive black hole binaries in gas-rich galaxy mergers; multiple regimes of orbital decay and interplay with gas inflows

    Science.gov (United States)

    Mayer, Lucio

    2013-12-01

    We revisit the phases of the pairing and sinking of black holes (BHs) in galaxy mergers and circumnuclear discs in light of the results of recent simulations with massive BHs embedded in predominantly gaseous backgrounds. After a general overview we highlight for the first time the existence of a clear transition, for unequal mass BHs, between the regime in which the orbital decay is dominated by the conventional dynamical friction wake and one in which global disc torques associated with density waves launched by the secondary BH as well as co-orbital torques arising from gas gravitationally captured by the BH dominate and lead to faster decay. The new regime intervenes at BH binary separations of a few tens of parsecs and below, following a phase of orbital circularization driven dynamical friction. It bears some resemblance with planet migration in protoplanetary discs. While the orbital timescale is reasonably matched by the migration rate for the Type-I regime, the dominant negative torque arises near the co-rotation resonance, which is qualitatively similar to what is found in the so-called Type-III migration, the fastest migration regime identified so far for planets. This fast decay rate brings the BHs to separations of order 10-1 pc, the resolution limit of our simulations, in less than ˜107 yr in a smooth disc, while the decay timescale can increase to >108 yr in clumpy discs due to gravitational scattering with molecular clouds. Eventual gap opening at sub-pc scale separations will slow down the orbital decay subsequently. How fast the binary BH can reach the separation at which gravitational waves take over will be determined by the nature of the interaction with the circumbinary disc and the complex torques exerted the gas flowing through the edge of such disc, the subject of many recent studies. We also present a new intriguing connection between the conditions required for rapid orbital decay of massive BH binaries and those required for prominent

  6. Physical and orbital properties of the Trojan asteroids

    CERN Document Server

    Melita, M D; Jones, D C; Williams, I P

    2008-01-01

    All the Trojan asteroids orbit about the Sun at roughly the same heliocentric distance as Jupiter. Differences in the observed visible reflection spectra range from neutral to red, with no ultra-red objects found so far. Given that the Trojan asteroids are collisionally evolved, a certain degree of variability is expected. Additionally, cosmic radiation and sublimation are important factors in modifying icy surfaces even at those large heliocentric distances. We search for correlations between physical and dynamical properties, we explore relationships between the following four quantities; the normalised visible reflectivity indexes ($S'$), the absolute magnitudes, the observed albedos and the orbital stability of the Trojans. We present here visible spectroscopic spectra of 25 Trojans. This new data increase by a factor of about 5 the size of the sample of visible spectra of Jupiter Trojans on unstable orbits. The observations were carried out at the ESO-NTT telescope (3.5m) at La Silla, Chile, the ING-WHT ...

  7. Orbital parameters for the two young binaries VSB 111 and VSB 126

    Energy Technology Data Exchange (ETDEWEB)

    Karnath, N.; Prato, L.; Wasserman, L. H.; Skiff, B. A. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Mathieu, R. D., E-mail: nicole@lowell.edu, E-mail: lprato@lowell.edu, E-mail: lhw@lowell.edu, E-mail: bas@lowell.edu, E-mail: gtorres@cfa.harvard.edu, E-mail: mathieu@astro.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2013-12-01

    We report orbital parameters for two low-mass, pre-main-sequence, double-lined spectroscopic binaries: VSB 111 and VSB 126. These systems were originally identified as single-lined on the basis of visible-light observations. We obtained high-resolution infrared spectra with the 10 m Keck II telescope, detected absorption lines of the secondary stars, and measured radial velocities of both components in the systems. The visible-light spectra were obtained with the 1.5 m Wyeth reflector at the Oak Ridge Observatory, the 1.5 m Tillinghast reflector at the F. L. Whipple Observatory, and the 4.5 m equivalent Multiple Mirror Telescope. The combination of our visible and infrared observations of VSB 111 leads to a period of 902.1 ± 0.9 days, an eccentricity of 0.788 ± 0.008, and a mass ratio of 0.52 ± 0.05. VSB 126 has a period of 12.9244 ± 0.0002 days, an eccentricity of 0.18 ± 0.02, and a mass ratio of 0.29 ± 0.02. Visible-light photometry, using the 0.8 m telescope at Lowell Observatory, provided rotation periods for the primary stars in both systems: 3.74 ± 0.02 days for VSB 111 and 5.71 ± 0.07 days for VSB 126. Both binaries are located in the young, active star-forming cluster NGC 2264 at a distance of ∼800 pc. The difference in the center-of-mass velocities of the two systems is consistent with the radial velocity gradient seen across NGC 2264. To test the evolutionary models for accuracy and consistency, we compare the stellar properties derived from several sets of theoretical calculations for pre-main-sequence evolution with our dynamical results.

  8. The Araucaria Project: High-precision orbital parallax and masses of the eclipsing binary TZ Fornacis

    Science.gov (United States)

    Gallenne, A.; Pietrzyński, G.; Graczyk, D.; Konorski, P.; Kervella, P.; Mérand, A.; Gieren, W.; Anderson, R. I.; Villanova, S.

    2016-02-01

    Context. Independent distance estimates are particularly useful to check the precision of other distance indicators, while accurate and precise masses are necessary to constrain evolution models. Aims: The goal is to measure the masses and distance of the detached eclipsing-binary TZ For with a precision level lower than 1% using a fully geometrical and empirical method. Methods: We obtained the first interferometric observations of TZ For with the VLTI/PIONIER combiner, which we combined with new and precise radial velocity measurements to derive its three-dimensional orbit, masses, and distance. Results: The system is well resolved by PIONIER at each observing epoch, which allowed a combined fit with eleven astrometric positions. Our derived values are in a good agreement with previous work, but with an improved precision. We measured the mass of both components to be M1 = 2.057 ± 0.001 M⊙ and M2 = 1.958 ± 0.001 M⊙. The comparison with stellar evolution models gives an age of the system of 1.20 ± 0.10 Gyr. We also derived the distance to the system with a precision level of 1.1%: d = 185.9 ± 1.9 pc. Such precise and accurate geometrical distances to eclipsing binaries provide a unique opportunity to test the absolute calibration of the surface brightness-colour relation for late-type stars, and will also provide the best opportunity to check on the future Gaia measurements for possible systematic errors. Based on observations made with ESO telescopes at Paranal observatory under program IDs 094.D-0320.The calibrated interferometric data as OIFITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A35

  9. The eccentric massive binary V380 Cyg: revised orbital elements and interpretation of the intrinsic variability of the primary component

    CERN Document Server

    Tkachenko, A; Aerts, C; Pavlovski, K; Southworth, J; Papics, P I; Moravveji, E; Kolbas, V; Tsymbal, V; Debosscher, J; Clemer, K

    2013-01-01

    We present a detailed analysis and interpretation of the high-mass binary V380 Cyg, based on high-precision space photometry gathered with the Kepler space mission as well as high-resolution ground-based spectroscopy obtained with the HERMES spectrograph attached to the 1.2m Mercator telescope. We derive a precise orbital solution and the full physical properties of the system, including dynamical component mass estimates of 11.43+/-0.19 and 7.00+/-0.14 solar masses for the primary and secondary, respectively. Our frequency analysis reveals the rotation frequency of the primary in both the photometric and spectroscopic data and additional low-amplitude stochastic variability at low frequency in the space photometry with characteristics that are compatible with recent theoretical predictions for gravity-mode oscillations excited either by the convective core or by sub-surface convective layers. Doppler Imaging analysis of the silicon lines of the primary suggests the presence of two high-contrast stellar surfa...

  10. CIRCUMBINARY PLANETS ORBITING THE RAPIDLY PULSATING SUBDWARF B-TYPE BINARY NY Vir

    Energy Technology Data Exchange (ETDEWEB)

    Qian, S.-B.; Zhu, L.-Y.; Dai, Z.-B.; He, J.-J. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences (CAS), P.O. Box 110, 650011 Kunming (China); Fernandez-Lajus, E. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires (Argentina); Xiang, F.-Y., E-mail: qsb@ynao.ac.cn [Physics Department, Xiangtan University, 411105 Xiangtan, Funan Province (China)

    2012-02-15

    We report here the tentative discovery of a Jovian planet in orbit around the rapidly pulsating subdwarf B-type (sdB-type) eclipsing binary NY Vir. By using newly determined eclipse times together with those collected from the literature, we detect that the observed-calculated (O - C) curve of NY Vir shows a small-amplitude cyclic variation with a period of 7.9 yr and a semiamplitude of 6.1 s, while it undergoes a downward parabolic change (revealing a period decrease at a rate of P-dot = -9.2 x 10{sup -12}). The periodic variation was analyzed for the light-travel-time effect via the presence of a third body. The mass of the tertiary companion was determined to be M{sub 3}sin i' = 2.3({+-} 0.3)M{sub Jupiter} when a total mass of 0.60 M{sub Sun} for NY Vir is adopted. This suggests that it is most probably a giant circumbinary planet orbiting NY Vir at a distance of about 3.3 astronomical units (AU). Since the rate of period decrease cannot be explained by true angular momentum loss caused by gravitational radiation or/and magnetic braking, the observed downward parabolic change in the O - C diagram may be only a part of a long-period (longer than 15 years) cyclic variation, which may reveal the presence of another Jovian planet ({approx}2.5 M{sub Jupiter}) in the system.

  11. Orbital Parameters for the Two Young Binaries VSB 111 and VSB 126

    CERN Document Server

    Karnath, Nicole; Wasserman, Larry; Torres, Guillermo; Skiff, Brian; Mathieu, Robert

    2013-01-01

    We report orbital parameters for two low-mass, pre-main sequence, double-lined spectroscopic binaries VSB 111 and VSB 126. These systems were originally identified as single-lined on the basis of visible-light observations. We obtained high-resolution, infrared spectra with the 10-m Keck II telescope, detected absorption lines of the secondary stars, and measured radial velocities of both components in the systems. The visible light spectra were obtained on the 1.5-m Wyeth reflector at the Oak Ridge Observatory, the 1.5-m Tillinghast reflector at the F. L. Whipple Observatory, and the 4.5-m equivalent Multiple Mirror Telescope. The combination of our visible and infrared observations of VSB 111 leads to a period of 902.1+/-0.9 days, an eccentricity of 0.788+/-0.008, and a mass ratio of 0.52+/-0.05. VSB 126 has a period of 12.9244+/-0.0002 days, an eccentricity of 0.18+/-0.02, and a mass ratio of 0.29+/-0.02. Visible-light photometry, using the 0.8-m telescope at Lowell Observatory, provided rotation periods f...

  12. NANOGrav Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries in Circular Orbits

    CERN Document Server

    Arzoumanian, Z; Burke-Spolaor, S; Chamberlin, S J; Chatterjee, S; Cordes, J M; Demorest, P B; Deng, X; Dolch, T; Ellis, J A; Ferdman, R D; Finn, L S; Garver-Daniels, N; Jenet, F; Jones, G; Kaspi, V M; Koop, M; Lam, M; Lazio, T J W; Lommen, A N; Lorimer, D R; Luo, J; Lynch, R S; Madison, D R; McLaughlin, M; McWilliams, S T; Nice, D J; Palliyaguru, N; Pennucci, T T; Ransom, S M; Sesana, A; Siemens, X; Stairs, I H; Stinebring, D R; Stovall, K; Swiggum, J; Vallisneri, M; van Haasteren, R; Wang, Y; Zhu, W W

    2014-01-01

    The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project currently observes 43 pulsars using the Green Bank and Arecibo radio telescopes. In this work we use a subset of 17 pulsars timed for a span of roughly five years (2005--2010). We analyze these data using standard pulsar timing models, with the addition of time-variable dispersion measure and frequency-variable pulse shape terms. Within the timing data, we perform a search for continuous gravitational waves from individual supermassive black hole binaries in circular orbits using robust frequentist and Bayesian techniques. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 pulsar dataset we place a 95% upper limit on the sky-averaged strain amplitude of $h_0\\lesssim 3.8\\times 10^{-14}$ at a frequency of 10 nHz. Furthermore, we place 95% ...

  13. NEW PRECISION ORBITS OF BRIGHT DOUBLE-LINED SPECTROSCOPIC BINARIES. VIII. HR 1528, HR 6993, 2 SAGITTAE, AND 18 VULPECULAE

    Energy Technology Data Exchange (ETDEWEB)

    Fekel, Francis C.; Williamson, Michael H. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Boulevard, Box 9501, Nashville, TN 37209 (United States); Tomkin, Jocelyn, E-mail: fekel@evans.tsuniv.edu, E-mail: michael.h.williamson@gmail.com, E-mail: jt@alexis.as.utexas.edu [Astronomy Department and McDonald Observatory, University of Texas, Austin, TX 78712 (United States)

    2013-11-01

    Improved orbital elements for four A-star double-lined spectroscopic binaries have been determined with numerous new radial velocities. Three of the four systems, HR 1528, 2 Sge, and 18 Vul, have moderately short orbital periods of 7.05, 7.39, and 9.31 days, respectively, and also have circular or nearly circular orbits. Only HR 6993 with a period of 14.68 days has a significantly eccentric orbit. The close visual companion of 2 Sge has been detected spectroscopically, and its velocity measured. The orbital dimensions (a {sub 1} sin i and a {sub 2} sin i) and minimum masses (m {sub 1} sin{sup 3} i and m {sub 2} sin{sup 3} i) of the short-period binary components all have accuracies of 0.5% or better. We determine basic properties of the individual stars and compare them with solar-abundance evolutionary tracks to estimate their masses. Half of the eight components may be synchronously or pseudosynchronously rotating.

  14. An Analytic Method to determine Habitable Zones for S-Type Planetary Orbits in Binary Star Systems

    OpenAIRE

    Eggl, Siegfried; Pilat-Lohinger, Elke; Georgakarakos, Nikolaos; Gyergyovits, Markus; Funk, Barbara

    2012-01-01

    With more and more extrasolar planets discovered in and around binary star systems, questions concerning the determination of the classical Habitable Zone arise. Do the radiative and gravitational perturbations of the second star influence the extent of the Habitable Zone significantly, or is it sufficient to consider the host-star only? In this article we investigate the implications of stellar companions with different spectral types on the insolation a terrestrial planet receives orbiting ...

  15. A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

    CERN Document Server

    D'Orazio, Daniel J; Duffell, Paul; Farris, Brian D; MacFadyen, Andrew I

    2015-01-01

    Graham et al. (2015) have detected a 5.2 year periodic optical variability of the quasar PG 1302-102 at redshift $z=0.3$, which they interpret as the redshifted orbital period $(1+z)t_{\\rm bin}$ of a putative supermassive black hole binary (SMBHB). Here we consider the implications of a $3-8$ times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal--mass SMBHBs ($q\\equiv M_2/M_1\\gtrsim 0.3$). With the corresponding $2-4$ times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fueled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter $t_{\\rm bin}$, among bright quasars, would be reduced by 1-2 orders of magnitude, compared to the 5.2 year period, in better agreement with the rarity of candidates reported by Graham et al. (2015). Finally, shorter periods would imply higher binary speeds, possibly imprin...

  16. A Computational Guide to Physics of Eclipsing Binaries. Paper I. Demonstrations and Perspectives

    CERN Document Server

    Prsa, A

    2005-01-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability. The operability of all these extensions is demonstrated on a synthetic main-sequence test binary; applications to real data will be published in follow-up papers. PHOEBE is released under the GNU Ge...

  17. Accretion and Orbital Inspiral in Gas-Assisted Supermassive Black Hole Binary Mergers

    CERN Document Server

    Rafikov, Roman R

    2016-01-01

    Many galaxies are expected to harbor binary supermassive black holes (SMBHs) in their centers. Their interaction with the surrounding gas results in accretion and exchange of angular momentum via tidal torques, facilitating binary inspiral. Here we explore the non-trivial coupling between these two processes and analyze how the global properties of externally supplied circumbinary disks depend on the binary accretion rate. By formulating our results in terms of the angular momentum flux driven by internal stresses, we come up with a very simple classification of the possible global disk structures, which differ from the standard constant $\\dot M$ accretion disk solution. Suppression of accretion by the binary tides, leading to a significant mass accumulation in the inner disk, accelerates binary inspiral. We show that once the disk region strongly perturbed by the viscously transmitted tidal torque exceeds the binary semi-major axis, the binary can merge in less than its mass-doubling time due to accretion. T...

  18. Physical and Geometrical Parameters of CVBS X: The Spectroscopic Binary Gliese 762.1

    CERN Document Server

    Masda, Suhail G; Neuhäuser, Ralph; Al-Naimiy, Hamid M

    2016-01-01

    We present the physical and geometrical parameters of the individual components of the close visual double-lined spectroscopic binary system Gliese 762.1, which were estimated using Al-Wardat's complex method for analyzing close visual binary systems. The estimated parameters of the individual components of the system are as follows: radius $R_{A}=0.845\\pm0.09 R_\\odot$, $R_{B}=0.795\\pm0.10 R_\\odot$, effective temperature $T_{\\rm eff}^{A} =5300\\pm50$\\,K, $T_{\\rm eff}^{B} =5150\\pm50$\\,K, surface gravity log $g_{A}=4.52\\pm0.10$, log $g_{B}=4.54\\pm0.15$ and luminosity $L_A=0.51\\pm0.08 L_\\odot$, $L_B=0.40\\pm0.07L_\\odot$. New orbital elements are presented with a semi-major axis of $0.0865 \\pm 0.010 $ arcsec using the Hippracos parallax $\\pi=58.96\\pm0.65$ mas, and an accurate total mass and individual masses of the system are determined as $M=1.72\\pm0.60M_\\odot$, $M_A=0.89 \\pm0.08M_\\odot$ and $M_B=0.83 \\pm0.07M_\\odot$. Finally, the spectral types and luminosity classes of both components are assigned as K0V and K1....

  19. Analysis of the Motion of the Extrasolar Planet HD 120136 Ab in a Binary System: Calculating Unknown Angular Orbital Elements

    Science.gov (United States)

    Plávalová, E.; Solovay, N. A.

    2015-07-01

    We have carried out an analysis of the motion of an extrasolar planet orbiting in a binary system, as a particular case of the three-body problem. The following assumptions have been made: a) the planet orbits around one of the binary components (the parent star); b) the distance between the stellar components is greater than that between the parent star and the orbiting planet (the ratio of the semi-major axes is a small parameter); c) the mass of the planet is smaller than the mass of the star, but is not negligible. We employed the Hamiltonian of the system without short-period terms, and we expanded it in terms of Legendre polynomials and truncated the expansion after the second-order terms. Such form of the Hamiltonian enables us to solve the differential equations of motion of our system and analyze of the motion of the extrasolar planet. We have applied this theory to the system HD 120136, and described the possible regions in which the planet can move. The theory permits us to calculate an unknown angular orbital element for the planet HD 120136 Ab, the ascending node: Ω1=134°±14°. The motion of the planet is expected to be stable over long time scales.

  20. The puzzling orbital period evolution of the low mass X-ray binary AX J1745.6-2901

    CERN Document Server

    Ponti, G; Munoz-Darias, T; Stella, L; Nandra, K

    2015-01-01

    The orbital period evolution of X-ray binaries provides fundamental clues to understanding mechanisms of angular momentum loss from these systems. We present an X-ray eclipse timing analysis of the transient low mass X-ray binary AX J1745.6-2901. This system shows full eclipses and thus is one of the few objects for which accurate orbital evolution studies using this method can be carried out. We report on XMM-Newton and ASCA observations covering 30 complete X-ray eclipses spanning an interval of more than 20 years. We improve the determination of the orbital period to a relative precision of $2\\times10^{-8}$, two orders of magnitudes better than previous estimates. We determine, for the first time, a highly significant rate of decrease of the orbital period $\\dot{P}_{orb}=-4.03\\pm0.32\\times10^{-11}$~s/s. This is at least one order of magnitude larger than expected from conservative mass transfer and angular momentum losses due to gravitational waves and magnetic breaking, and might result from non-conservat...

  1. Reconceiling the orbital and physical properties of the martian moons

    CERN Document Server

    Ronnet, Thomas; Mousis, Olivier; Brugger, Bastien; Beck, Pierre; Devouard, Bertrand; Witasse, Olivier; Cipriani, Fabrice

    2016-01-01

    The origin of Phobos and Deimos is still an open question. Currently, none of the three proposed scenarios for their origin (intact capture of two distinct outer solar system small bodies, co-accretion with Mars, and accretion within an impact-generated disk) is able to reconcile their orbital and physical properties. Here, we investigate the expected mineralogical composition and size of the grains from which the moons once accreted assuming they formed within an impact-generated accretion disk. A comparison of our results with the present day spectral properties of the moons allows us to conclude that their building blocks cannot originate from a magma phase, thus preventing their formation in the innermost part of the disk. Instead, gas-to-solid condensation of the building blocks in the outer part of an extended gaseous disk is found as a possible formation mechanism as it does allow reproducing both the spectral and physical properties of the moons. Such a scenario may finally reconcile their orbital and...

  2. Binary galaxies and alternative physics. I. A qualitative application of MOND and Mannheim-Kazanas gravity

    OpenAIRE

    Soares, D. S. L.

    1995-01-01

    Binary galaxies are modeled as point-masses obeying the non-Newtonian MOND and Mannheim-Kazanas (MKG) theories of gravity. Random samples of such systems are generated by means of Monte Carlo simulations of binary orbits. Model pairs have total masses and mass ratios similar to pairs in the cataloged sample used in the analysis. General features of synthetic samples are derived from a comparison with observed data of galaxy pairs in $R \\times \\Delta V/(L_1+L_2)^{1/2} $ space. Both MOND and Ma...

  3. Physical parameter study of eight W Ursae Majoris-type contact binaries in NGC 188

    CERN Document Server

    Chen, Xiaodian; de Grijs, Richard; Zhang, Xiaobin; Xin, Yu; Wang, Kun; Luo, Changqing; Yan, Zhengzhou; Tian, Jianfeng; Sun, Jinjiang; Liu, Qili; Zhou, Qiang; Luo, Zhiquan

    2016-01-01

    We used the newly commissioned 50 cm Binocular Network (50BiN) telescope at Qinghai Station of Purple Mountain Observatory (Chinese Academy of Sciences) to observe the old open cluster NGC 188 in V and R as part of a search for variable objects. Our time-series data span a total of 36 days. Radial velocity and proper-motion selection resulted in a sample of 532 genuine cluster members. Isochrone fitting was applied to the cleaned cluster sequence, yielding a distance modulus of (m - M)0V = 11.35 \\pm 0.10 mag and a total foreground reddening of E(V - R) = 0.062 \\pm 0.002 mag. Light-curve solutions were obtained for eight W Ursae Majoris eclipsing-binary systems (W UMas) and their orbital parameters were estimated. Using the latter parameters, we estimate a distance to the W UMas which is independent of the host cluster's physical properties. Based on combined fits to six of the W UMas (EP Cep, EQ Cep, ES Cep, V369 Cep, and--for the first time--V370 Cep and V782 Cep), we obtain an average distance modulus of (m...

  4. The LEECH Exoplanet Imaging Survey: Orbit and Component Masses of the Intermediate-age, Late-type Binary NO UMa

    Science.gov (United States)

    Schlieder, Joshua E.; Skemer, Andrew J.; Maire, Anne-Lise; Desidera, Silvano; Hinz, Philip; Skrutskie, Michael F.; Leisenring, Jarron; Bailey, Vanessa; Defrère, Denis; Esposito, Simone; Strassmeier, Klaus G.; Weber, Michael; Biller, Beth A.; Bonnefoy, Mickaël; Buenzli, Esther; Close, Laird M.; Crepp, Justin R.; Eisner, Josh A.; Hofmann, Karl-Heinz; Henning, Thomas; Morzinski, Katie M.; Schertl, Dieter; Weigelt, Gerd; Woodward, Charles E.

    2016-02-01

    We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBT Interferometer Exozodi Exoplanet Common Hunt exoplanet imaging survey. Our H-, Ks-, and L‧-band observations resolve the system at angular separations <0.″09. The components exhibit significant orbital motion over a span of ∼7 months. We combine our imaging data with archival images, published speckle interferometry measurements, and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses. The masses of the K2.0 ± 0.5 primary and K6.5 ± 0.5 secondary are 0.83 ± 0.02 M⊙ and 0.64 ± 0.02 M⊙, respectively. We also derive a system distance of d = 25.87 ± 0.02 pc and revise the Galactic kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as a nuclear member of the ∼500 Myr old Ursa Major moving group, and it is thus a mass and age benchmark. We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group. We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models. NO UMa joins the short list of nearby, bright, late-type binaries having known ages and fully characterized orbits. Based on data obtained with the STELLA robotic telescope in Tenerife, an AIP facility jointly operated by AIP and IAC.

  5. PHOTOMETRIC PROPERTIES OF SELECTED ALGOL-TYPE BINARIES. III. AL GEMINORUM AND BM MONOCEROTIS WITH POSSIBLE LIGHT-TIME ORBITS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y.-G.; Dai, H.-F. [School of Physics and Electronic Information, Huaibei Normal University, 235000 Huaibei, Anhui Province (China); Li, H.-L., E-mail: yygcn@163.com [National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing (China)

    2012-01-15

    We present the CCD photometry of two Algol-type binaries, AL Gem and BM Mon, observed from 2008 November to 2011 January. With the updated Wilson-Devinney program, photometric solutions were deduced from their EA-type light curves. The mass ratios and fill-out factors of the primaries are found to be q{sub ph} = 0.090({+-} 0.005) and f{sub 1} = 47.3%({+-} 0.3%) for AL Gem, and q{sub ph} = 0.275({+-} 0.007) and f{sub 1} = 55.4%({+-} 0.5%) for BM Mon, respectively. By analyzing the O-C curves, we discovered that the periods of AL Gem and BM Mon change in a quasi-sinusoidal mode, which may possibly result from the light-time effect via the presence of a third body. Periods, amplitudes, and eccentricities of light-time orbits are 78.83({+-} 1.17) yr, 0fd0204({+-}0fd0007), and 0.28({+-} 0.02) for AL Gem and 97.78({+-} 2.67) yr, 0fd0175({+-}0fd0006), and 0.29({+-} 0.02) for BM Mon, respectively. Assumed to be in a coplanar orbit with the binary, the masses of the third bodies would be 0.29 M{sub Sun} for AL Gem and 0.26 M{sub Sun} for BM Mon. This kind of additional companion can extract angular momentum from the close binary orbit, and such processes may play an important role in multiple star evolution.

  6. Physical elements of the eclipsing binary δ Orionis

    Czech Academy of Sciences Publication Activity Database

    Mayer, P.; Harmanec, P.; Wolf, M.; Božič, H.; Šlechta, Miroslav

    2010-01-01

    Roč. 520, Sep-Oct (2010), A89/1-A89/12. ISSN 0004-6361 R&D Projects: GA ČR GA205/06/0584 Grant ostatní: GA ČR(CZ) GA205/06/0304; GA ČR(CZ) GAP209/10/0715 Institutional research plan: CEZ:AV0Z10030501 Keywords : eclipsing binaries * early-type stars * fundamental parameters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

  7. Post-Newtonian Theory for Precision Doppler Measurements of Binary Star Orbits

    OpenAIRE

    Kopeikin, S. M.; Ozernoy, L. M.

    1998-01-01

    The determination of velocities of stars from precise Doppler measurements is described here using relativistic theory of astronomical reference frames so as to determine the Keplerian and post-Keplerian parameters of binary systems. We apply successive Lorentz transformations and the relativistic equation of light propagation to establish the exact treatment of Doppler effect in binary systems both in special and general relativity theories. As a result, the Doppler shift is a sum of (1) lin...

  8. Shaping point- and mirror-symmetric proto-planetary nebulae by the orbital motion of the central binary system

    CERN Document Server

    Haro-Corzo, Sinhue A R; Raga, Alejandro C; Riera, Angels; Kajdic, Primoz

    2009-01-01

    We present 3D hydrodynamical simulations of a jet launched from the secondary star of a binary system inside a proto-planetary nebula. The secondary star moves around the primary in a close eccentric orbit. From the gasdynamic simulations we compute synthetic [NII] 6583 emission maps. Different jet axis inclinations with respect to the orbital plane, as well as different orientations of the flow with respect to the observer are considered. For some parameter combinations, we obtain structures that show point- or mirror-symmetric morphologies depending on the orientation of the flow with respect to the observer. Furthermore, our models can explain some of the emission distribution asymmetries that are summarized in the classification given by Soker & hadar (2002).

  9. Calibration Binaries

    Science.gov (United States)

    Drummond, J.

    2011-09-01

    Two Excel Spreadsheet files are offered to help calibrate telescope or camera image scale and orientation with binary stars for any time. One is a personally selected list of fixed position binaries and binaries with well-determined orbits, and the other contains all binaries with published orbits. Both are derived from the web site of the Washington Double Star Library. The spreadsheets give the position angle and separation of the binaries for any entered time by taking advantage of Excel's built in iteration function to solve Kepler's transcendental equation.

  10. Orbit and spin evolution of synchronous binary stars on the main sequence (a theoretical improvement to the analytical method)

    International Nuclear Information System (INIS)

    This paper provides a method to study the solution of equations for synchronous binary stars with large eccentricity on the main sequence. The theoretical results show that the evolution of the eccentricity is linear with time or follows an exponential form, and the semi-major axis and spin vary with time in an exponential form that are different from the results given in a previous paper. The improved method is applicable in both cases of large eccentricity and small eccentricity. In addition, the number of terms in the expansion of a series with small eccentricity is very long due to the series converging slowly. The advantage of this method is that it is applicable to cases with large eccentricity due to the series converging quickly. This paper chooses the synchronous binary star V1143 Cyg that is on the main sequence and has a large eccentricity (e = 0.54) as an example calculation and gives the numerical results. Lastly, the evolutionary tendency including the evolution of orbit and spin, the time for the speed up of spin, the circularization time, the orbital collapse time and the life time are given in the discussion and conclusion. The results shown in this paper are an improvement on those from the previous paper. (paper)

  11. Precise Orbital Solutions for KEPLER Eclipsing Binaries of W UMa Type Showing Total Eclipses

    Science.gov (United States)

    Şenavcı, H. V.; Doǧruel, M. B.; Nelson, R. H.; Yılmaz, M.; Selam, S. O.

    2016-09-01

    We aim to discover the accuracy of photometric mass ratios (q ph) determined for eclipsing binary stars, in the case of the system having at least one `flat bottom' as a minimum profile, as well as the accuracy of data used in that sense. Within this context, we present the results of two-dimensional grid search (q - i) for some W UMa-type eclipsing binaries showing total eclipses, based on the high precision photometric data provided by the KEPLER Mission. The radial velocity data obtained for KIC10618253 in this study, enables us to compare both q ph and the corresponding spectroscopic mass ratio (q sp) values. The results indicate that the high precision photometric data for overcontact eclipsing binaries showing total eclipses allow us to obtain the photometric mass ratios as accurate as the spectroscopic values.

  12. S-TYPE AND P-TYPE HABITABILITY IN STELLAR BINARY SYSTEMS: A COMPREHENSIVE APPROACH. II. ELLIPTICAL ORBITS

    Energy Technology Data Exchange (ETDEWEB)

    Cuntz, M., E-mail: cuntz@uta.edu [Department of Physics, University of Texas at Arlington, Arlington, TX 76019-0059 (United States)

    2015-01-10

    In the first paper of this series, a comprehensive approach has been provided for the study of S-type and P-type habitable regions in stellar binary systems, which was, however, restricted to circular orbits of the stellar components. Fortunately, a modest modification of the method also allows for the consideration of elliptical orbits, which of course entails a much broader range of applicability. This augmented method is presented here, and numerous applications are conveyed. In alignment with Paper I, the selected approach considers a variety of aspects, which comprise the consideration of a joint constraint including orbital stability and a habitable region for a possible system planet through the stellar radiative energy fluxes ({sup r}adiative habitable zone{sup ;} RHZ). The devised method is based on a combined formalism for the assessment of both S-type and P-type habitability; in particular, mathematical criteria are deduced for which kinds of systems S-type and P-type habitable zones are realized. If the RHZs are truncated by the additional constraint of orbital stability, the notation of ST-type and PT-type habitability applies. In comparison to the circular case, it is found that in systems of higher eccentricity, the range of the RHZs is significantly reduced. Moreover, for a considerable number of models, the orbital stability constraint also reduces the range of S-type and P-type habitability. Nonetheless, S-, P-, ST-, and PT-type habitability is identified for a considerable set of system parameters. The method as presented is utilized for BinHab, an online code available at The University of Texas at Arlington.

  13. Physical properties of trans-neptunian binaries (120347) Salacia-Actaea and (42355) Typhon-Echidna

    NARCIS (Netherlands)

    Stansberry, J. A.; Grundy, W. M.; Mueller, M.; Benecchi, S. D.; Rieke, G. H.; Noll, K. S.; Buie, M. W.; Levison, H. F.; Porter, S. B.; Roe, H. G.

    2012-01-01

    We report new Hubble Space Telescope and Spitzer Space Telescope results concerning the physical properties of the trans-neptunian object (TNO) binaries (120347) Salacia-Actaea (formerly 2004 SB60), and (42355) Typhon-Echidna (formerly 2002 CR46). The mass of the (120347) Salacia-Actaea system is 4.

  14. A Computational Guide to Physics of Eclipsing Binaries. I. Demonstrations and Perspectives

    Science.gov (United States)

    Prša, A.; Zwitter, T.

    2005-07-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program of Wilson & Devinney. This introductory paper gives an overview of the most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining, and proper treatment of the reddening), numerical innovations (suggested improvements to WD's differential corrections method, the new Nelder & Mead downhill simplex method), and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability. The operability of all these extensions is demonstrated on a synthetic main-sequence test binary; applications to real data will be published in follow-up papers. PHOEBE is released under the GNU General Public License, which guarantees it to be free and open to anyone interested in joining in on future development.

  15. Observable gravitational and electromagnetic orbits and trajectories in discrete physics

    International Nuclear Information System (INIS)

    Our discrete and finite version of relativistic quantum mechanics provides an elementary particle physics consistent with the standard model of quarks and leptons. Our recent relativistic calculation of the bound state spectrum of hydrogen has allowed us to make a combinatorial correction to the first order estimate of 1/α = /Dirac h/c/e2 = 137 derived from the combinatorial hierarchy and achieve agreement with experiment up to terms of order α3. The same theory requires that to first order /Dirac h/c/Gm/sub p/2 = 2127 + 136 ≅ 1.7 /times/ 1038. Using the emission and absorption of spin 1 photons and spin 2 gravitons in this framework, we try to show that we can meet the three additional tests of general relativity---solar red shift, solar bending of light, and precession of the perihelion of Mercury. We predict that a macroscopic electromagnetic orbit would have four times the Sommerfeld precession for basically the same reason that Mercury has six times the Sommerfeld precession. 20 refs

  16. Massive Black Hole binaries in gas-rich galaxy mergers; multiple regimes of orbital decay and interplay with gas inflows

    CERN Document Server

    Mayer, Lucio

    2013-01-01

    We revisit the phases of the pairing and sinking of BHs in galaxy mergers and circunmunclear disks in light of the results of recent simulations with massive BHs embedded in predominantly gaseous backgrounds. After a general overview we discuss the importance of a fast orbital decay regime dominated by global disk torques rather than by the local dynamical friction wake. This regime can dominate at BH binary separations of a few tens of parsecs and below, following a phase of orbital circularization dominated by local dynamical friction. It is similar to Type-I migration in planetary evolution. It can bring the black holes to separations small enough for gravitational waves to take over on a timescale ranging from less than $\\sim 10^7$ yr to up to $10^8$ yr, depending on whether the interstellar medium is smooth or clumpy. Eventual gap opening at sub-pc scale separations slows down but does not interrupt the orbital decay.Subsequently, we discuss a new intriguing connection between the conditions required for...

  17. Suzaku Monitoring of Hard X-ray Emission from Eta Carinae over a Single Binary Orbital Cycle

    CERN Document Server

    Hamaguchi, Kenji; Takahashi, Hiromitsu; Yuasa, Takayuki; Ishida, Manabu; Gull, Theodore R; Pittard, Julian M; Russell, Christopher M P; Madura, Thomas I

    2014-01-01

    The Suzaku X-ray observatory monitored the supermassive binary system Eta Carinae 10 times during the whole 5.5 year orbital cycle between 2005-2011. This series of observations presents the first long-term monitoring of this enigmatic system in the extremely hard X-ray band between 15-40 keV. During most of the orbit, the 15-25 keV emission varied similarly to the 2-10 keV emission, indicating an origin in the hard energy tail of the kT ~4 keV wind-wind collision (WWC) plasma. However, the 15-25 keV emission declined only by a factor of 3 around periastron when the 2-10 keV emission dropped by two orders of magnitude due probably to an eclipse of the WWC plasma. The observed minimum in the 15-25 keV emission occurred after the 2-10 keV flux had already recovered by a factor of ~3. This may mean that the WWC activity was strong, but hidden behind the thick primary stellar wind during the eclipse. The 25-40 keV flux was rather constant through the orbital cycle, at the level measured with INTEGRAL in 2004. Thi...

  18. S-Type and P-Type Habitability in Stellar Binary Systems: A Comprehensive Approach. II. Elliptical Orbits

    CERN Document Server

    Cuntz, Manfred

    2014-01-01

    In the first paper of this series, a comprehensive approach has been provided for the study of S-type and P-type habitable regions in stellar binary systems, which was, however, restricted to circular orbits of the stellar components. Fortunately, a modest modification of the method also allows for the consideration of elliptical orbits, which of course entails a much broader range of applicability. This augmented method is presented here, and numerous applications are conveyed. In alignment with Paper I, the selected approach considers a variety of aspects, which comprise the consideration of a joint constraint including orbital stability and a habitable region for a putative system planet through the stellar radiative energy fluxes (radiative habitable zone; RHZ). The devised method is based on a combined formalism for the assessment of both S-type and P-type habitability; in particular, mathematical criteria are deduced for which kinds of systems S-type and P-type habitable zones are realized. If the RHZs ...

  19. Physical Identification of Binary System of Gliclazide-Hydrophilic Polymers Using X-Ray Diffraction

    Science.gov (United States)

    Rachmawati, H.; Yatinasari, Faizatun, Syarie, S. A.

    2008-03-01

    The formation of binary system in pharmaceutical solid state is aimed to improve the physicochemical characteristics of active compound, such as its solubility. To identify the physical change of the binary system including crystallinity or particle morphology, there are many methods can be applied. In present report, we study the physical interaction of the binary system of gliclazide and hydrophilic polymers. In this binary system, gliclazide was either dispersed or mixed with polyvinyl pirrolidone (PVP K30) or polyethylene glycol (PEG 6000). The dispersion system of gliclazide in the polymeric carriers was prepared by solvation-evaporation method, using dichloromethane/methylene chloride as an organic solvent. The physical characterization of both dispersed and mixed of gliclazide was studied using X-ray diffraction at interval 6-50 °/2θ. As a comparison, the same procedure was performed for pure gliclazide. To confirm the diffractogram of this binary system, Fourier Transform Infrared (FT-IR) spectroscopy was carried out as well. Both diffarctogram and FT-IR spectra revealed that there was no new compound formed in the solid dispersion system of gliclazide:PEG 6000 and gliclazide:PVP K30. In contrast, the solubility as well as the dissolution rate of gliclazide in the presence of both hydrophilic polymers was increased as compared to pure gliclazide. We conclude therefore that solvatation followed by evaporation of gliclazide in the presence of either PEG 6000 or PVP K30 did not alter its crystalline characteristic. The improved of gliclazide solubility in the binary system might due to other mechanism such as increased in the wettability and the hydrophylicity effect of the polymers.

  20. Next-to-next-to-leading order post-Newtonian spin-orbit Hamiltonian for self-gravitating binaries

    CERN Document Server

    Hartung, Johannes

    2011-01-01

    We present the next-to-next-to-leading order post-Newtonian (PN) spin-orbit Hamiltonian for two self-gravitating spinning compact objects. If at least one of the objects is rapidly rotating, then the corresponding interaction is comparable in strength to a 3.5PN effect. The result in the present paper in fact completes the knowledge of the post-Newtonian Hamiltonian for binary spinning black holes up to and including 3.5PN. The Hamiltonian is checked via known results for the test-spin case and via the global Poincar\\'e algebra with the center-of-mass vector uniquely determined by an ansatz.

  1. Absolute parameters and physical nature of two W-UMa type binaries: V1123 Tau and V1128 Tau

    Institute of Scientific and Technical Information of China (English)

    Xiao-Bin Zhang; An-Bin Ren; Chang-Qing Luo; Yang-Ping Luo

    2011-01-01

    We present high-precision, multi-band CCD photometry of two less-studied close binaries V 1123 Tau and V 1128 Tau. Complete covered light curves and a number of new times of light minima of the two eclipsing systems were obtained, based on which, revised orbital elements and new ephemerides were given. By adopting the Wilson-Devinney method, the light curves were analyzed. The photometric solutions confirm the W UMa-type nature of the binary systems. With the less-massive secondary slightly cooler than the primary, V1123 Tau could be classified as an Atype contact system. While V 1128 Tau is typically considered a W-type W UMa star,the surface temperature of its secondary component is determined to be absolutely higher than the primary by about 270 K. Combining with the results of radial-velocity solutions, we determined absolute parameters of the two systems. The mass, radius and luminosity for each component of V1123 Tau were derived as: 1.36 ± 0.05M☉,1.37 ±- 0.02R☉, and 2.01 ±± 0.07L☉ and 0.40 ± 0.02M☉, 0.80 ± 0.01R☉, and 0.67 ± 0.04L☉, respectively. For V1128 Tau, the absolute parameters were computed to be 1.09 ± 0.03M☉, 1.01 ± 0.01R☉, and 1.34 ± 0.06L☉ and 0.58 ± 0.01M☉,0.76 ±- 0.01R☉, and 0.91 ± 0.05L☉, respectively. Based on these results, the evolutionary status and the physical nature of the two binary systems are discussed, while also connecting with the theoretical models.

  2. VLBI observations of the shortest orbital period black hole binary, MAXI J1659-152

    Science.gov (United States)

    Paragi, Z.; van der Horst, A. J.; Belloni, T.; Miller-Jones, J. C. A.; Linford, J.; Taylor, G.; Yang, J.; Garrett, M. A.; Granot, J.; Kouveliotou, C.; Kuulkers, E.; Wijers, R. A. M. J.

    2013-06-01

    The X-ray transient MAXI J1659-152 was discovered by Swift/Burst Alert Telescope and it was initially identified as a gamma-ray burst. Soon its Galactic origin and binary nature were established. There exists a wealth of multiwavelength monitoring data for this source, providing a great coverage of the full X-ray transition in this candidate black hole binary system. We obtained two epochs of European very long baseline interferometry (VLBI) Network (EVN) electronic-VLBI and four epochs of Very Long Baseline Array data of MAXI J1659-152 which show evidence for outflow in the early phases. The overall source properties (polarization, milliarcsecond-scale radio structure, flat radio spectrum) are described well with the presence of a compact jet in the system through the transition from the hard-intermediate to the soft X-ray spectral state. The apparent dependence of source size and the radio core position on the observed flux density (luminosity-dependent core shift) supports this interpretation as well. We see no evidence for major discrete ejecta during the outburst. For the source proper motion we derive 2σ upper limits of 115 μas d-1 in right ascension, and 37 μas d-1 in declination, over a time baseline of 12 d. These correspond to velocities of 1400 and 440 km s-1, respectively, assuming a source distance of ˜7 kpc.

  3. Orbitally modulated dust formation by the WC7+O5 colliding-wind binary WR140

    CERN Document Server

    Williams, P M; Marston, A P; Moffat, A F J; Varricatt, W P; Dougherty, S M; Kidger, M R; Morbidelli, L; Tapia, M

    2009-01-01

    We present high-resolution infrared (2--18 micron) images of the archetypal periodic dust-making Wolf-Rayet binary system WR140 (HD 193793) taken between 2001 and 2005, and multi-colour (J -- [19.5]) photometry observed between 1989 and 2001. The images resolve the dust cloud formed by WR140 in 2001, allowing us to track its expansion and cooling, while the photometry allows tracking the average temperature and total mass of the dust. The combination of the two datasets constrains the optical properties of the dust. The most persistent dust features, two concentrations at the ends of a `bar' of emission to the south of the star, were observed to move with constant proper motions of 324+/-8 and 243+/-7 mas/y. Longer wavelength (4.68-micron and 12.5-micron) images shows dust emission from the corresponding features from the previous (1993) periastron passage and dust-formation episode. A third persistent dust concentration to the east of the binary (the `arm') was found to have a proper motion ~ 320 mas/y. Extr...

  4. The LEECH Exoplanet Imaging Survey: Orbit and Component Masses of the Intermediate Age, Late-Type Binary NO UMa

    CERN Document Server

    Schlieder, Joshua E; Maire, Anne-Lise; Desidera, Silvano; Hinz, Philip; Skrutskie, Michael F; Leisenring, Jarron; Bailey, Vanessa; Defrere, Denis; Esposito, Simone; Strassmeier, Klaus G; Weber, Michael; Biller, Beth A; Bonnefoy, Mickael; Buenzli, Esther; Close, Laird M; Crepp, Justin R; Eisner, Josh A; Hofmann, Karl-Heinz; Henning, Thomas; Morzinski, Katie M; Schertl, Dieter; Weigelt, Gerd; Woodward, Charles E

    2015-01-01

    We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBTI Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey. Our H, K$_s$, and L'-band observations resolve the system at angular separations <0.09". The components exhibit significant orbital motion over a span of ~7 months. We combine our imaging data with archival images, published speckle interferometry measurements, and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses. The masses of the K2.0$\\pm$0.5 primary and K6.5$\\pm$0.5 secondary are 0.83$\\pm$0.02 M$_{\\odot}$ and 0.64$\\pm$0.02 M$_{\\odot}$, respectively. We also derive a system distance of d = 25.87$\\pm$0.02 pc and revise the Galactic kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as a nuclear member of the ~500 Myr old Ursa Major moving group and it is thus a mass and age benchmark. We compare the masses of the NO UMa bi...

  5. The Orbit of the L dwarf + T dwarf Spectral Binary SDSS J080531.84+481233.0

    CERN Document Server

    Burgasser, Adam J; Gelino, Christopher R; Sahlmann, Johannes; Gagliuffi, Daniella Bardalez

    2016-01-01

    [abridged] We report four years of radial velocity monitoring observations of SDSS J080531.84+481233.0 that reveal significant and periodic variability, confirming the binary nature of the source. We infer an orbital period of 2.02$\\pm$0.03 yr, a semi-major axis of 0.76$^{+0.05}_{-0.06}$ AU, and an eccentricity of 0.46$\\pm$0.05, consistent with the amplitude of astrometric variability and prior attempts to resolve the system. Folding in constraints based on the spectral types of the components (L4$\\pm$0.7 and T5.5$\\pm$1.1), corresponding effective temperatures, and brown dwarf evolutionary models, we further constrain the orbital inclination of this system to be nearly edge-on (90$^o\\pm$19$^o$), and deduce a large system mass ratio (M$_2$/M$_1$ = 0.86$^{+0.10}_{-0.12}$), substellar components (M$_1$ = 0.057$^{+0.016}_{-0.014}$ M$_{\\odot}$, M$_2$ = 0.048$^{+0.008}_{-0.010}$ M$_{\\odot}$), and a relatively old system age (minimum age = 4.0$^{+1.9}_{-1.2}$ Gyr). The measured projected rotational velocity of the p...

  6. A Circumbinary Planet in Orbit Around the Short-Period White-Dwarf Eclipsing Binary RR Cae

    CERN Document Server

    Qian, S -B; Zhu, L -Y; Dai, Z -B; Lajus, E Fernandez; Baume, G L

    2012-01-01

    By using six new determined mid-eclipse times together with those collected from the literature, we found that the Observed-Calculated (O-C) curve of RR Cae shows a cyclic change with a period of 11.9 years and an amplitude of 14.3s, while it undergoes an upward parabolic variation (revealing a long-term period increase at a rate of dP/dt =+4.18(+-0.20)x10^(-12). The cyclic change was analyzed for the light-travel time effect that arises from the gravitational influence of a third companion. The mass of the third body was determined to be M_3*sin i' = 4.2(+-0.4) M_{Jup} suggesting that it is a circumbinary giant planet when its orbital inclination is larger than 17.6 degree. The orbital separation of the circumbinary planet from the central eclipsing binary is about 5.3(+-0.6)AU. The period increase is opposite to the changes caused by angular momentum loss via magnetic braking or/and gravitational radiation, nor can it be explained by the mass transfer between both components because of its detached configur...

  7. The Banana Project. III. Spin-orbit Alignment in the Long-period Eclipsing Binary NY Cephei

    CERN Document Server

    Albrecht, Simon; Carter, Joshua; Snellen, Ignas; de Mooij, Ernst

    2010-01-01

    Binaries are not always neatly aligned. Previous observations of the DI Her system showed that the spin axes of both stars are highly inclined with respect to one another and the orbital axis. Here we report on a measurement of the spin-axis orientation of the primary star of the NY Cep system, which is similar to DI Her in many respects: it features two young early-type stars (~6 Myr, B0.5V+B2V), in an eccentric and relatively long-period orbit (e=0.48, P=15.d3). The sky projections of the rotation vector and the spin vector are well-aligned (beta_p = 2 +- 4 degrees), in strong contrast to DI Her. Although no convincing explanation has yet been given for the misalignment of DI Her, our results show that the phenomenon is not universal, and that a successful theory will need to account for the different outcome in the case of NY Cep.

  8. On using the beaming effect to measure spin-orbit alignment in stellar binaries with Sun-like components

    CERN Document Server

    Shporer, Avi; Mazeh, Tsevi; Zucker, Shay

    2011-01-01

    The beaming effect (aka Doppler boosting) induces a variation in the observed flux of a luminous object, following its observed radial velocity variation. We describe a photometric signal induced by the beaming effect during eclipse of binary systems, where the stellar components are late type Sun-like stars. The shape of this signal is sensitive to the angle between the eclipsed star's spin axis and the orbital angular momentum axis, thereby allowing its measurement. We show that during eclipse there are in fact two effects, superimposed on the known eclipse light curve. One effect is produced by the rotation of the eclipsed star, and is the photometric analog of the spectroscopic Rossiter-McLaughlin effect, thereby it contains information about the sky-projected spin-orbit angle. The other effect is produced by the varying weighted difference, during eclipse, between the beaming signals of the two stars. We give approximated analytic expressions for the amplitudes of the two effects, and present a numerical...

  9. The final spin from binary black holes in quasi-circular orbits

    OpenAIRE

    Hofmann, Fabian; Barausse, Enrico; Rezzolla, Luciano

    2016-01-01

    We revisit the problem of predicting the spin magnitude and direction of the black hole resulting from the merger of two black holes with arbitrary masses and spins inspiralling in quasi-circular orbits. We do this by analyzing a catalog of 641 recent numerical-relativity simulations collected from the literature and spanning a large variety of initial conditions. By combining information from the post-Newtonian approximation, the extreme mass-ratio limit and perturbative calculations, we imp...

  10. Exoplanets in binary star systems: on the switch from prograde to retrograde orbits

    Science.gov (United States)

    Carvalho, J. P. S.; Mourão, D. C.; de Moraes, R. Vilhena; Prado, A. F. B. A.; Winter, O. C.

    2016-01-01

    The eccentric Kozai-Lidov mechanism, based on the secular theory, has been proposed as a mechanism that plays an important role in producing orbits that switch from prograde to retrograde. In the present work we study the secular dynamics of a triple system composed of a Sun-like central star and a Jupiter-like planet, which are under the gravitational influence of another perturbing star (brown dwarf). The perturbation potential is developed in closed form up to the fifth order in a small parameter (α =a1/a2), where a1 is the semimajor axis of the extrasolar planet and a2 is the semimajor axis of the perturbing star. To eliminate the short-period terms of the perturbation potential, the double-average method is applied. In this work we do not eliminate the nodes, a standard method in the literature, before deriving the equations of motion. The main goal is to study the effects of the higher-order terms of the expansion of the perturbing force due to the third body in the orbital evolution of the planet. In particular, we investigate the inclination and the shape (eccentricity) of these orbits. We show the importance of the higher-order terms in changing the inversion times of the flip, i.e., the times where the inclination of the inner planet flips from prograde to retrograde trajectories. We also show the dependence of the first flip with respect to the semimajor axis and eccentricity of the orbit of the planet. The general conclusion is that the analytical model increases its accuracy with the inclusion of higher-order terms. We also performed full numerical integrations using the Bulirsch-Stoer method available in the Mercury package for comparison with the analytical model. The results obtained with the equations developed in this work are in accordance with direct numerical simulations.

  11. Motion and gravitational wave forms of eccentric compact binaries with orbital-angular-momentum-aligned spins under next-to-leading order in spin-orbit and leading order in spin(1)-spin(2) and spin-squared couplings

    Energy Technology Data Exchange (ETDEWEB)

    Tessmer, M; Hartung, J; Schaefer, G, E-mail: m.tessmer@uni-jena.d [Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany)

    2010-08-21

    A quasi-Keplerian parameterization for the solutions of second post-Newtonian (PN) accurate equations of motion for spinning compact binaries is obtained including leading order spin-spin and next-to-leading order spin-orbit interactions. Rotational deformation of the compact objects is incorporated. For arbitrary mass ratios the spin orientations are taken to be parallel or anti-parallel to the orbital angular momentum vector. The emitted gravitational wave forms are given in analytic form up to 2PN point particle, 1.5PN spin-orbit and 1PN spin-spin contributions, whereby the spins are assumed to be of 0PN order.

  12. Motion and gravitational wave forms of eccentric compact binaries with orbital-angular-momentum-aligned spins under next-to-leading order in spin-orbit and leading order in spin(1)-spin(2) and spin-squared couplings

    International Nuclear Information System (INIS)

    A quasi-Keplerian parameterization for the solutions of second post-Newtonian (PN) accurate equations of motion for spinning compact binaries is obtained including leading order spin-spin and next-to-leading order spin-orbit interactions. Rotational deformation of the compact objects is incorporated. For arbitrary mass ratios the spin orientations are taken to be parallel or anti-parallel to the orbital angular momentum vector. The emitted gravitational wave forms are given in analytic form up to 2PN point particle, 1.5PN spin-orbit and 1PN spin-spin contributions, whereby the spins are assumed to be of 0PN order.

  13. The Orbit of the L Dwarf + T Dwarf Spectral Binary SDSS J080531.84+481233.0

    Science.gov (United States)

    Burgasser, Adam J.; Blake, Cullen H.; Gelino, Christopher R.; Sahlmann, Johannes; Bardalez Gagliuffi, Daniella

    2016-08-01

    SDSS J080531.84+481233.0 is a closely separated, very-low-mass (VLM) binary identified through combined-light spectroscopy and confirmed as an astrometric variable. Here we report four years of radial velocity monitoring observations of the system that reveal significant and periodic variability, confirming the binary nature of the source. We infer an orbital period of 2.02 ± 0.03 years, a semimajor axis of 0.76{}-0.06+0.05 au, and an eccenticity of 0.46 ± 0.05, consistent with the amplitude of astrometric variability and prior attempts to resolve the system. Folding in constraints based on the spectral types of the components (L4 ± 0.7 and T5.5 ± 1.1), corresponding effective temperatures, and brown dwarf evolutionary models, we further constrain the orbital inclination of this system to be nearly edge-on (90° ± 19°), and deduce a large system mass ratio (M 2/M 1 = {0.86}-0.12+0.10), substellar components (M 1 = {0.057}-0.014+0.016 M ⊙, M 2 = {0.048}-0.010+0.008 M ⊙), and a relatively old system age (minimum age = {4.0}-1.2+1.9 Gyr). The measured projected rotational velocity of the primary ({V}{rot}\\sin i = 34.1 ± 0.7 km s‑1) implies that this inactive source is a rapid rotator (period ≲ 3 hr) and a viable system for testing spin–orbit alignment in VLM multiples. Robust model-independent constraints on the component masses may be possible through measurement of the reflex motion of the secondary at wavelengths in which it contributes a greater proportion of the combined luminence, while the system may also be resolvable through sparse-aperature mask interferometry with adaptive optics. The combination of well-determined component atmospheric properties and masses near and/or below the hydrogen minimum mass make SDSS J0805+4812AB an important system for future tests of brown dwarf evolutionary models. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California

  14. Determining the Physical Lens Parameters of the Binary Gravitational Microlensing Event MOA-2009-BLG-016

    CERN Document Server

    Hwang, K -H; Bond, I A; Miyake, N; Abe, F; Bennett, D P; Botzler, C S; Fukui, A; Furusawa, K; Hayashi, F; Hearnshaw, J B; Hosaka, S; Itow, Y; Kamiya, K; Kilmartin, P M; Korpela, A; Lin, W; Ling, C H; Makita, S; Masuda, K; Matsubara, Y; Muraki, Y; Nishimoto, K; Ohnishi, K; Perrott, Y C; Rattenbury, N; Saito, To; Sako, T; Skuljan, L; Sullivan, D J; Sumi, T; Suzuki, D; Sweatman, W L; P.,; Tristram, J; Wada, K; L., P C M Yock D; Depoy,; Gaudi, B S; Gould, A; Lee, C -U; Pogge, R W

    2010-01-01

    We report the result of the analysis of the light curve of the microlensing event MOA-2009-BLG-016. The light curve is characterized by a short-duration anomaly near the peak and an overall asymmetry. We find that the peak anomaly is due to a binary companion to the primary lens and the asymmetry of the light curve is explained by the parallax effect caused by the acceleration of the observer over the course of the event due to the orbital motion of the Earth around the Sun. In addition, we detect evidence for the effect of the finite size of the source near the peak of the event, which allows us to measure the angular Einstein radius of the lens system. The Einstein radius combined with the microlens parallax allows us to determine the total mass of the lens and the distance to the lens. We identify three distinct classes of degenerate solutions for the binary lens parameters, where two are manifestations of the previously identified degeneracies of close/wide binaries and positive/negative impact parameters...

  15. Suzaku monitoring of hard X-ray emission from η Carinae over a single binary orbital cycle

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Kenji; Corcoran, Michael F. [CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States); Takahashi, Hiromitsu [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yuasa, Takayuki [Nishina Center, RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Ishida, Manabu [Institute of Space and Astronautical Science/JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Gull, Theodore R.; Madura, Thomas I. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Pittard, Julian M. [School of Physics and Astronomy, The University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Russell, Christopher M. P. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)

    2014-11-10

    The Suzaku X-ray observatory monitored the supermassive binary system η Carinae 10 times during the whole 5.5 yr orbital cycle between 2005 and 2011. This series of observations presents the first long-term monitoring of this enigmatic system in the extremely hard X-ray band between 15 and 40 keV. During most of the orbit, the 15-25 keV emission varied similarly to the 2-10 keV emission, indicating an origin in the hard energy tail of the kT ∼ 4 keV wind-wind collision (WWC) plasma. However, the 15-25 keV emission declined only by a factor of three around periastron when the 2-10 keV emission dropped by two orders of magnitude due probably to an eclipse of the WWC plasma. The observed minimum in the 15-25 keV emission occurred after the 2-10 keV flux had already recovered by a factor of ∼3. This may mean that the WWC activity was strong, but hidden behind the thick primary stellar wind during the eclipse. The 25-40 keV flux was rather constant through the orbital cycle, at the level measured with INTEGRAL in 2004. This result may suggest a connection of this flux component to the γ-ray source detected in this field. The helium-like Fe Kα line complex at ∼6.7 keV became strongly distorted toward periastron as seen in the previous cycle. The 5-9 keV spectra can be reproduced well with a two-component spectral model, which includes plasma in collision equilibrium and a plasma in non-equilibrium ionization (NEI) with τ ∼ 10{sup 11} cm{sup –3} s{sup –1}. The NEI plasma increases in importance toward periastron.

  16. Multiwavelength optical observations of chromospherically active binary systems V. FF UMa (2RE J0933+624): a system with orbital period variation

    CERN Document Server

    Gálvez, M C; Fernández-Figueroa, M J; De Castro, E; Cornide, M

    2007-01-01

    This is the fifth paper in a series aimed at studying the chromospheres of active binary systems using several optical spectroscopic indicators to obtain or improve orbital solution and fundamental stellar parameters. We present here the study of FF UMa (2RE J0933+624), a recently discovered, X-ray/EUV selected, active binary with strong H_alpha emission. The objectives of this work are, to find orbital solutions and define stellar parameters from precise radial velocities and carry out an extensive study of the optical indicators of chromospheric activity. We obtained high resolution echelle spectroscopic observations during five observing runs from 1998 to 2004. We found radial velocities by cross correlation with radial velocity standard stars to achieve the best orbital solution. We also measured rotational velocity by cross-correlation techniques and have studied the kinematic by galactic space- velocity components (U, V, W) and Eggen criteria. Finally, we have determined the chromospheric contribution i...

  17. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    Science.gov (United States)

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen

    2014-01-01

    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  18. Orbital Parameters for the $250 M_\\odot$ Eta Carinae Binary System

    CERN Document Server

    Kashi, Amit

    2015-01-01

    We show that recent observations of He I and N II lines of Eta Carinae support an orbital orientation where the secondary star is closest to us at periastron passages. This conclusion is valid both for the commonly assumed masses of the two stars, and for the higher stellar masses model where the very massive evolved primary star mass is $M_1=170 M_\\odot$ and its hot secondary star mass is $M_2 = 80 M_\\odot$. The later model better explains the change in the orbital period assuming that the ninetieth century Great Eruption was powered by accretion onto the secondary star. Adopting the commonly used high eccentricity $e \\simeq 0.9$ and inclination $i=41^\\circ$, we obtain a good fit to newly released Doppler shift observations of He I emission and absorption lines assuming they are emitted and absorbed in the acceleration zone of the secondary stellar wind. Our conclusion that the secondary star is in the foreground at periastron reverses an opposite view presented recently in the literature.

  19. Contribution to the search for binaries among Am stars - VIII. New spectroscopic orbits of eight systems and statistical study of a sample of 91 Am stars

    Science.gov (United States)

    Carquillat, J.-M.; Prieur, J.-L.

    2007-09-01

    This paper is the last of a series devoted to the study of Am stars, with the monitoring of radial velocities of a sample of 91 objects during more than 20 yr. The purpose was to determine which stars were members of spectroscopic binaries (SBs) and study in detail those systems in order to obtain observational constraints on the origin of the Am phenomenon. In the first part, we present the results of a detailed study of eight Am stars (HD 32893, 60489, 109762, 111057, 113697, 204918, 219675 and BD+44° 4512) observed at the Haute-Provence and Cambridge observatories with CORAVEL instruments. We find that these objects are single-lined SBs whose orbital elements are determined for the first time. HD 32893 is found to be a triple spectroscopic system whose third body might be detected by speckle interferometry. Physical parameters are inferred for the primaries of those SBs. We then investigate the influence of tidal interaction and find that it has already led to the synchronism of the primaries and to the circularization of the orbits of four of those systems. In the second part of this paper, we present the main results of our whole programme and derive some statistical properties of Am stars. We give the recapitulating table of the orbital parameters found for the SBs of our whole sample and the list of those for which no evidence for radial velocity variations could be found during our monitoring. Our study shows that at least 64 per cent of Am stars are members of SBs. This rate is significantly greater than that of normal stars. Although some SBs may have been not detected, this study shows that a substantial fraction of Am stars do not belong to SBs: they are either isolated stars or members of wide binary systems. We then present some statistical properties of the orbital parameters of the SBs whose primary is an Am star, on an extended sample obtained by adding 29 Am SB orbits published by other authors. The corresponding e versus logP diagram shows a cut

  20. The formation of low-mass helium white dwarfs orbiting pulsars: Evolution of low-mass X-ray binaries below the bifurcation period

    CERN Document Server

    Istrate, Alina; Langer, Norbert

    2014-01-01

    Millisecond pulsars (MSPs) are generally believed to be old neutron stars (NSs) which have been spun up to high rotation rates via accretion of matter from a companion star in a low-mass X-ray binary (LMXB). However, many details of this recycling scenario remain to be understood. Here we investigate binary evolution in close LMXBs to study the formation of radio MSPs with low-mass helium white dwarf companions (He WDs) in tight binaries with orbital periods P_orb = 2-9 hr. In particular, we examine: i) if such observed systems can be reproduced from theoretical modelling using standard prescriptions of orbital angular momentum losses (i.e. with respect to the nature and the strength of magnetic braking), ii) if our computations of the Roche-lobe detachments can match the observed orbital periods, and iii) if the correlation between WD mass and orbital period (M_WD, P_orb) is valid for systems with P_orb < 2 days. Numerical calculations with a detailed stellar evolution code were used to trace the mass-tra...

  1. Photometric observations of three high mass X-ray binaries and a search for variations induced by orbital motion

    International Nuclear Information System (INIS)

    We searched for long period variation in V-band, IC-band and RXTE X-ray light curves of the High Mass X-ray Binaries (HMXBs) LS 1698 / RX J1037.5-5647, HD 110432 / 1H 1249-637 and HD 161103 / RX J1744.7-2713 in an attempt to discover orbitally induced variation. Data were obtained primarily from the ASAS database and were supplemented by shorter term observations made with the 24- and 40-inch ANU telescopes and one of the robotic PROMPT telescopes. Fourier peri-odograms suggested the existence of long period variation in the V-band light curves of all three HMXBs, however folding the data at those periods did not reveal convincing periodic variation. At this point we cannot rule out the existence of long term V-band variation for these three sources and hints of longer term variation may be seen in the higher precision PROMPT data. Long term V-band observations, on the order of several years, taken at a frequency of at least once per week and with a precision of 0.01 mag, therefore still have a chance of revealing long term variation in these three HMXBs.

  2. The orbital phase resolved spectroscopy of X-ray binary 4U 1822‑371 with Suzaku

    Science.gov (United States)

    Niu, Shu; Yan, Shu-Ping; Lei, Shi-Jun; Nowak, Michael A.; Schulz, Norbert S.; Ji, Li

    2016-04-01

    4U 1822‑371 is a typical edge-on eclipsing low mass X-ray binary and the prototype of accretion disk coronal sources. We report on the results of a spectral analysis over the energy range 0.5–45 keV observed by Suzaku in 2006. We extract spectra from five orbital phases. The spectra can be equally well described by various previously proposed models: an optically thick model described by a partially covered cutoff power law and an optically thin model described by a blackbody plus a cutoff power law. The optically thick model requires a covering fraction of about 55%, while the optically thin model requires a temperature of the central source of about 0.16 keV. The spectrum in the optically thick model also shows the previously detected cyclotron line feature at ∼30 keV with the same Suzaku observation. This feature confirms the presence of a strong magnetic field. The Fe Kα fluorescent line strengths as well as the detected Fe XXVI strengths are similar to previous Chandra and XMM-Newton detections in our phased spectral analysis; however, we also observe strong Fe XXVI during the eclipse, which indicates a slightly larger central corona.

  3. The Araucaria Project: High-precision orbital parallax and masses of the eclipsing binary TZ~Fornacis

    CERN Document Server

    Gallenne, A; Graczyk, D; Konorski, P; Kervella, P; Mérand, A; Gieren, W; Anderson, R I; Villanova, S

    2016-01-01

    Context: Independent distance estimates are particularly useful to check the precision of other distance indicators, while accurate and precise masses are necessary to constrain evolution models. Aim: The goal is to measure the masses and distance of the detached eclipsing-binary TZ~For with a precision level lower than 1\\,\\% using a fully geometrical and empirical method. Method: We obtained the first interferometric observations of TZ~For with the VLTI/PIONIER combiner, which we combined with new and precise radial velocity measurements to derive its three-dimensional orbit, masses, and distance. Results: The system is well resolved by PIONIER at each observing epoch, which allowed a combined fit with eleven astrometric positions. Our derived values are in a good agreement with previous work, but with an improved precision. We measured the mass of both components to be $M_1 = 2.057 \\pm 0.001\\,M_\\odot$ and $M_2 = 1.958 \\pm 0.001\\,M_\\odot$. The comparison with stellar evolution models gives an age of the syst...

  4. Next-to-next-to-leading order spin–orbit effects in the near-zone metric and precession equations of compact binaries

    International Nuclear Information System (INIS)

    We extend our previous work devoted to the computation of the next-to-next-to-leading order spin–orbit correction (corresponding to 3.5PN order) in the equations of motion of spinning compact binaries by (i) deriving the corresponding spin–orbit terms in the evolution equations for the spins, the conserved integrals of the motion and the metric regularized at the location of the particles (obtaining also the metric all over the near zone but with some lower precision); (ii) performing the orbital reduction of the precession equations, near-zone metric and conserved integrals to the center-of-mass frame and then further assuming quasi-circular orbits (neglecting gravitational radiation reaction). The results are systematically expressed in terms of the spin variables with a conserved Euclidean norm instead of the original antisymmetric spin tensors of the pole–dipole formalism. This work paves the way to the future computation of the next-to-next-to-leading order spin–orbit terms in the gravitational-wave phasing of spinning compact binaries. (paper)

  5. The orbits of subdwarf B + main-sequence binaries. I: The sdB+G0 system PG 1104+243

    CERN Document Server

    Vos, J; Degroote, P; De Smedt, K; Green, E M; Heber, U; Van Winckel, H; Acke, B; Bloemen, S; De Cat, P; Exter, K; Lampens, P; Lombaert, R; Masseron, T; Menu, J; Neyskens, P; Raskin, G; Smolders, K; Tkachenko, A; Ringat, E; Rauch, T

    2012-01-01

    The predicted orbital period histogram of an sdB population is bimodal with a peak at short ( 250 days) periods. Observationally, there are many short-period sdB systems known, but only very few long-period sdB binaries are identified. As these predictions are based on poorly understood binary interaction processes, it is of prime importance to confront the predictions to observational data. In this contribution we aim to determine the absolute dimensions of the long-period sdB+MS binary system PG1104+243. High-resolution spectroscopy time-series were obtained with HERMES at the Mercator telescope at La Palma, and analyzed to obtain radial velocities of both components. Photometry from the literature was used to construct the spectral energy distribution (SED) of the binary. Atmosphere models were used to fit this SED and determine the surface gravity and temperature of both components. The gravitational redshift provided an independent confirmation of the surface gravity of the sdB component. An orbital peri...

  6. The quest for companions to post-common envelope binaries IV: The 2:1 mean-motion resonance of the planets orbiting NN Serpentis

    CERN Document Server

    Beuermann, Klaus; Hessman, Frederic V

    2013-01-01

    We present 69 new mid-eclipse times of the young post-common envelope binary (PCEB) NN Ser, which was previously suggested to possess two circumbinary planets. We have interpreted the observed eclipse-time variations in terms of the light-travel time effect caused by two planets, exhaustively covering the multi-dimensional parameter space by fits in the two binary and ten orbital parameters. We supplemented the fits by stability calculations for all models with an acceptable chi-square. An island of secularly stable 2:1 resonant solutions exists, which coincides with the global chi-square minimum. Our best-fit stable solution yields current orbital periods P_o = 15.47 yr and P_i = 7.65 yr and eccentricities e_o = 0.14 and e_i = 0.22 for the outer (o) and inner (i) planets, respectively. The companions qualify as giant planets, with masses of 7.0 M_Jup and 1.7 M_Jup for the case of orbits coplanar with that of the binary. The two-planet model that starts from the present system parameters has a lifetime greate...

  7. Physical properties of the gamma-ray binary LS 5039 through low and high frequency radio observations

    CERN Document Server

    Marcote, B; Paredes, J M; Ishwara-Chandra, C H

    2015-01-01

    We have studied in detail the 0.15-15 GHz radio spectrum of the gamma-ray binary LS 5039 to look for a possible turnover and absorption mechanisms at low frequencies, and to constrain the physical properties of its emission. We have analysed two archival VLA monitorings, all the available archival GMRT data and a coordinated quasi-simultaneous observational campaign conducted in 2013 with GMRT and WSRT. The data show that the radio emission of LS 5039 is persistent on day, week and year timescales, with a variability $\\lesssim 25~\\%$ at all frequencies, and no signature of orbital modulation. The obtained spectra reveal a power-law shape with a curvature below 5 GHz and a turnover at $\\sim0.5$ GHz, which can be reproduced by a one-zone model with synchrotron self-absorption plus Razin effect. We obtain a coherent picture for a size of the emitting region of $\\sim0.85~\\mathrm{mas}$, setting a magnetic field of $B\\sim20~\\mathrm{mG}$, an electron density of $n_{\\rm e}\\sim4\\times10^5~{\\rm cm^{-3}}$ and a mass-los...

  8. An eccentric binary millisecond pulsar in the Galactic plane

    NARCIS (Netherlands)

    D.J. Champion; S.M. Ransom; P. Lazarus; F. Camilo; C. Bassa; V.M. Kaspi; D.J. Nice; P.C.C. Freire; I.H. Stairs; J. van Leeuwen; B.W. Stappers; J.M. Cordes; J.W.T. Hessels; D.R. Lorimer; Z. Arzoumanian; D.C. Backer; N.D.R. Bhat; S. Chatterjee; I. Cognard; J.S. Deneva; C.A. Faucher-Giguère; B.M. Gaensler; J. Han; F.A. Jenet; L. Kasian; V.I. Kondratiev; M. Kramer; J. Lazio; M.A. McLaughlin; A. Venkataraman; W. Vlemmings

    2008-01-01

    Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+ 0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric ( e = 0.44) 95- day orbit around

  9. Orbiting.

    OpenAIRE

    Halford, Sarah Juliette

    2013-01-01

    I always knew I was from another planet. Earth was my home, yes, I liked hamburgers and roller coasters, but there was still an orbit in me that seemed out of place. My imaginative orbit felt like it didn't to spin the "normal" way. As a performer I spent more time alienating myself and judging how different I felt, rather than owning the creative space I lived in and applying it to my craft. My past three years at UC San Diego have been the perfect atmosphere for my artist self. I have been ...

  10. Josephson physics of spin-orbit coupled elongated Bose-Einstein condensates

    OpenAIRE

    Garcia-March, M. A.; Mazzarella, G.; Dell'Anna, L.; Juliá-Díaz, B.; Salasnich, L.; Polls, A.

    2014-01-01

    We consider an ultracold bosonic binary mixture confined in a one-dimensional double-well trap. The two bosonic components are assumed to be two hyperfine internal states of the same atom. We suppose that these two components are spin-orbit coupled between each other. We employ the two-mode approximation starting from two coupled Gross-Pitaevskii equations and derive a system of ordinary differential equations governing the temporal evolution of the inter-well population imbalance of each com...

  11. The Visual Orbit of the 1.1-day Spectroscopic Binary \\sigma^2 Coronae Borealis from Interferometry at the CHARA Array

    CERN Document Server

    Raghavan, Deepak; Torres, Guillermo; Latham, David W; Mason, Brian D; Boyajian, Tabetha S; Baines, Ellyn K; Williams, Stephen J; Brummelaar, Theo A ten; Farrington, Chris D; Ridgway, Stephen T; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H

    2008-01-01

    We present an updated spectroscopic orbit and a new visual orbit for the double-lined spectroscopic binary \\sigma^2 Coronae Borealis based on radial velocity measurements at the Oak Ridge Observatory in Harvard, Massachusetts and interferometric visibility measurements at the CHARA Array on Mount Wilson. \\sigma^2 CrB is composed of two Sun-like stars of roughly equal mass in a circularized orbit with a period of 1.14 days. The long baselines of the CHARA Array have allowed us to resolve the visual orbit for this pair, the shortest period binary yet resolved interferometrically, enabling us to determine component masses of 1.137 \\pm 0.037 M_sun and 1.090 \\pm 0.036 M_sun. We have also estimated absolute V-band magnitudes of MV (primary) = 4.35 \\pm 0.02 and MV(secondary) = 4.74 \\pm 0.02. A comparison with stellar evolution models indicates a relatively young age of 1-3 Gyr, consistent with the high Li abundance measured previously. This pair is the central component of a quintuple system, along with another simi...

  12. 3.9 day orbital modulation in the TeV gamma-ray flux and spectrum from the X-ray binary LS 5039

    CERN Document Server

    Aharonian, F A; Bazer-Bachi, A R; Beilicke, M; Benbow, W; Berge, D; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brown, A M; Buhler, R; Büsching, I; Carrigan, S; Chadwick, P M; Chounet, L M; Cornils, R; Costamante, L; Degrange, B; Dickinson, H J; Djannati-Ata, A; O'Connor-Drury, L; Dubus, G; Egberts, K; Emmanoulopoulos, D; Espigat, P; Feinstein, F; Ferrero, E; Fiasson, A; Fontaine, G; Funk, Seb; Funk, S; Fussling, M; Gallant, Y A; Giebels, B; Glicenstein, J F; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Horns, D; Jacholkowska, A; De Jager, O C; Kendziorra, E; Khelifi, B; Komin, N; Konopelko, A; Kosack, K; Latham, I J; Le Gallou, R; Lemiere, A; Lemoine-Goumard, M; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, G; McComb, T J L; Moulin, E; De Naurois, Mathieu; Nedbal, D; Nolan, S J; Noutsos, A; Orford, K J; Osborne, J L; Ouchrif, M; Panter, M; Pelletier, G; Pita, S; Pühlhofer, G; Punch, M; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, A; Reimer, O; Ripken, J; Rob, L; Rolland, L; Rowell, G; Sahakian, V V; Santangelo, A; Sauge, L; Schlenker, S; Schlickeiser, R; Schroder, R; Schwanke, U; Schwarzburg, S; Shalchi, A; Sol, H; Spangler, D; Spanier, F; Steenkamp, R; Stegmann, C; Superina, G; Tavernet, J P; Terrier, R; Tluczykont, M; Van Eldik, C; Vasileiadis, G; Venter, C; Vincent, P; Völk, H J; Wagner, S J; Ward, M

    2006-01-01

    New observations of LS 5039, a High Mass X-ray Binary comprising a massive star and compact object, were carried out with the High Energy Stereoscopic System of Cherenkov Telescopes (H.E.S.S.) in 2005 at very high energy (VHE) gamma-ray energies. These observations reveal that its flux and energy spectrum are modulated with the 3.9 day orbital period of the binary system. This is the first time in gamma-ray astronomy that orbital modulation has been observed, and periodicity clearly established using ground-based gamma-ray detectors. The VHE gamma-ray emission is largely confined to half of the orbit, peaking around the inferior conjunction epoch of the compact object. For this epoch, there is also a hardening of the energy spectrum in the energy range between 0.2 TeV and a few TeV. The flux vs. orbital phase profile provides the first clear indication of gamma-ray absorption via pair production within an astrophysical source, a process which is expected to occur if the gamma-ray production site is situated w...

  13. Physical Limitations of Nuclear Propulsion for Earth to Orbit

    Science.gov (United States)

    Blevins, John A.; Patton, Bruce; Rhys, Noah O.; Schafer, Charles F. (Technical Monitor)

    2001-01-01

    An assessment of current nuclear propulsion technology for application in Earth to Orbit (ETO) missions has been performed. It can be shown that current nuclear thermal rocket motors are not sufficient to provide single stage performance as has been stated by previous studies. Further, when taking a systems level approach, it can be shown that NTRs do not compete well with chemical engines where thrust to weight ratios of greater than I are necessary, except possibly for the hybrid chemical/nuclear LANTR (LOX Augmented Nuclear Thermal Rocket) engine. Also, the ETO mission requires high power reactors and consequently large shielding weights compared to NTR space missions where shadow shielding can be used. In the assessment, a quick look at the conceptual ASPEN vehicle proposed in 1962 in provided. Optimistic NTR designs are considered in the assessment as well as discussion on other conceptual nuclear propulsion systems that have been proposed for ETO. Also, a quick look at the turbulent, convective heat transfer relationships that restrict the exchange of nuclear energy to thermal energy in the working fluid and consequently drive the reactor mass is included.

  14. RADIATION EFFECTS IN PHYSICAL AGING OF BINARY As-S AND As-Se GLASSES

    International Nuclear Information System (INIS)

    Radiation-induced physical aging effects are studied in binary AsxS100-x and AsxSe100-x (30 (le) x (le) 42) glasses by conventional differential scanning calorimetry (DSC) method. It is shown that γ-irradiation (Co60 source, ∼ 3 MGy dose) of glassy AsxS100-x caused a measurable increase in glass transition temperature and endothermic peak area in the vicinity of glass transition region, which was associated with acceleration of structural relaxation processes in these materials. In contrast to sulfide glasses, the samples of As-Se family did not exhibit any significant changes in DSC curves after γ-irradiation. The observed difference in radiation-induced physical aging between sulfides and selenides was explained by more effective destruction-polymerization transformations and possible metastable defects formation in S-based glassy network.

  15. RADIATION EFFECTS IN PHYSICAL AGING OF BINARY As-S AND As-Se GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, Roman; Shpotyuk, O.; Kozdras, A.; Riley, Brian J.; Sundaram, S. K.; McCloy, John S.

    2011-01-24

    Radiation-induced physical aging effects are studied in binary AsxS100-x and AsxSe100-x (30 ≤ x ≤ 42) glasses by conventional differential scanning calorimetry (DSC) method. It is shown that γ-irradiation (Co60 source, ~ 3 MGy dose) of glassy AsxS100-x caused a measurable increase in glass transition temperature and endothermic peak area in the vicinity of glass transition region, which was associated with acceleration of structural relaxation processes in these materials. In contrast to sulfide glasses, the samples of As-Se family did not exhibit any significant changes in DSC curves after γ-irradiation. The observed difference in radiation-induced physical aging between sulfides and selenides was explained by more effective destruction-polymerization transformations and possible metastable defects formation in S-based glassy network.

  16. Theoretical Physics Implications of the Binary Black-Hole Merger GW150914

    CERN Document Server

    Yunes, Nicolas; Pretorius, Frans

    2016-01-01

    The gravitational-wave observation GW150914 by Advanced LIGO provides the first opportunity to learn about physics in the extreme gravity of coalescing binary black holes. The LIGO/Virgo collaboration has verified that this observation is consistent with General Relativity, constraining the presence of parametric anomalies in the signal. This paper expands this analysis to a larger class of anomalies, highlighting the inferences that can be drawn on non-standard theoretical physics mechanisms that would affect the signal. We find that GW150914 constrains a plethora of mechanisms associated with the generation and propagation of gravitational waves, including the activation of scalar fields, gravitational leakage into large extra dimensions, the variability of Newton's constant, the speed of gravity, a modified dispersion relation, gravitational Lorentz violation and the strong equivalence principle. Unlike other observations that limit these mechanisms, GW150914 is a direct probe of dynamical strong-field gra...

  17. Feasibility study of a zero-gravity (orbital) atmospheric cloud physics experiments laboratory

    Science.gov (United States)

    Hollinden, A. B.; Eaton, L. R.

    1972-01-01

    A feasibility and concepts study for a zero-gravity (orbital) atmospheric cloud physics experiment laboratory is discussed. The primary objective was to define a set of cloud physics experiments which will benefit from the near zero-gravity environment of an orbiting spacecraft, identify merits of this environment relative to those of groundbased laboratory facilities, and identify conceptual approaches for the accomplishment of the experiments in an orbiting spacecraft. Solicitation, classification and review of cloud physics experiments for which the advantages of a near zero-gravity environment are evident are described. Identification of experiments for potential early flight opportunities is provided. Several significant accomplishments achieved during the course of this study are presented.

  18. Orbital decay of the PSR J0045-7319\\/B star binary system age of radio pulsar and initial spin of neutron star

    CERN Document Server

    Lai, D

    1996-01-01

    Recent timing observations of PSR J0045-7319 reveal that the neutron star/B star binary orbit is decaying on a time scale of |\\Porb/\\dot\\Porb|=0.5 Myr, shorter than the characteristic age (\\tau_c=3 Myr) of the pulsar (Kaspi et al.~1996a). We study mechanisms for the orbital decay. The standard weak friction theory based on static tide requires far too short a viscous time to explain the observed \\dot\\Porb. We show that dynamical tidal excitation of g-modes in the B star can be responsible for the orbital decay. However, to explain the observed short decay timescale, the B star must have some significant retrograde rotation with respect to the orbit --- The retrograde rotation brings lower-order g-modes, which couple much more strongly to the tidal potential, into closer ``resonances'' with the orbital motion, thus significantly enhancing the dynamical tide. A much less likely possibility is that the g-mode damping time is much shorter than the ordinary radiative damping time. The observed orbital decay timesc...

  19. Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K.; McCloy, John S.; Riley, Brian J.; Murphy, Mark K.; Qiao, Hong (Amy); Windisch, Charles F.; Walter, Eric D.; Crum, Jarrod V.; Golovchak, Roman; Shpotyuk, O.

    2012-03-01

    Gamma radiation induces changes in physical, optical, and structural properties in chalcogenide glasses., Previous research has focused on As{sub 2}S{sub 3} and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As-S binary glass series. Binary As{sub x}S{sub 100-x} (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a {sup 60}Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, x-ray diffraction, and Raman spectrum. These results are compared to those of as-made and 1 year aged samples. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation in these glasses. XRD, Raman, and EPR data provide supporting evidence, underscoring the importance of optimally- or overly-constrained structures for stability under aging or irradiation.

  20. Radio Emission and Orbital Motion from the Close-encounter Star-Brown Dwarf Binary WISE J072003.20-084651.2

    Science.gov (United States)

    Burgasser, Adam J.; Melis, Carl; Todd, Jacob; Gelino, Christopher R.; Hallinan, Gregg; Bardalez Gagliuffi, Daniella

    2015-12-01

    We report the detection of radio emission and orbital motion from the nearby star-brown dwarf binary WISE J072003.20-084651.2AB. Radio observations across the 4.5-6.5 GHz band with the Very Large Array identify at the position of the system quiescent emission with a flux density of 15 ± 3 μJy, and a highly polarized radio source that underwent a 2-3 minute burst with peak flux density 300 ± 90 μJy. The latter emission is likely a low-level magnetic flare similar to optical flares previously observed for this source. No outbursts were detected in separate narrow-band Hα monitoring observations. We report new high-resolution imaging and spectroscopic observations that confirm the presence of a co-moving T5.5 secondary and provide the first indications of three-dimensional orbital motion. We used these data to revise our estimates for the orbital period (4.1{}-1.3+2.7 year) and tightly constrain the orbital inclination to be nearly edge-on (93.°6+1.°6-1.°4), although robust measures of the component and system masses will require further monitoring. The inferred orbital motion does not change the high likelihood that this radio-emitting very low-mass binary made a close pass to the Sun in the past 100 kyr. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  1. Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation

    Science.gov (United States)

    Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

    1995-01-01

    Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be

  2. Simulation of physical sputtering of metal surface: certification of modified method of binary collisions

    International Nuclear Information System (INIS)

    A modified method of binary collisions and its application for simulation of metal surface sputtering is considered. The conventional methods possess an insufficient speed of response and incomplete adequacy to the experiment. The proposed model possesses a considerably higher speed of response and fuller account of factors affecting the spUttering process. A particular attention is given to the problem of experimental certification of the program. Using as an example physical sputtering of nickel and copper by nickel- and argon ions, respectively, a perfect agreement bitween model results and the experiment is shown: the sputtering coefficient dependence on the ion energy and incidence angle, angular- and energy distributions of sputtered atoms. Studies on prospects for using the new method are considered

  3. The quest for companions to post-common envelope binaries. IV. The 2:1 mean-motion resonance of the planets orbiting NN Serpentis

    Science.gov (United States)

    Beuermann, K.; Dreizler, S.; Hessman, F. V.

    2013-07-01

    We present 69 new mid-eclipse times of the young post-common envelope binary (PCEB) NN Ser, which was previously suggested to possess two circumbinary planets. We have interpreted the observed eclipse-time variations in terms of the light-travel time effect caused by two planets, exhaustively covering the multi-dimensional parameter space by fits in the two binary and ten orbital parameters. We supplemented the fits by stability calculations for all models with an acceptable χ2. An island of secularly stable 2:1 resonant solutions exists, which coincides with the global χ2 minimum. Our best-fit stable solution yields current orbital periods Po = 15.47 yr and Pi = 7.65 yr and eccentricities eo = 0.14 and ei = 0.22 for the outer and inner planets, respectively. The companions qualify as giant planets, with masses of 7.0 MJup and 1.7 MJup for the case of orbits coplanar with that of the binary. The two-planet model that starts from the present system parameters has a lifetime greater than 108 yr, which significantly exceeds the age of NN Ser of 106 yr as a PCEB. The resonance is characterized by libration of the resonant variable Θ1 and circulation of , the difference between the arguments of periapse of the two planets. No stable nonresonant solutions were found, and the possibility of a 5:2 resonance suggested previously by us is now excluded at the 99.3% confidence level. Table 1 is available in electronic form at http://www.aanda.org

  4. Binary Neutron Star Mergers

    Directory of Open Access Journals (Sweden)

    Joshua A. Faber

    2012-07-01

    Full Text Available We review the current status of studies of the coalescence of binary neutron star systems. We begin with a discussion of the formation channels of merging binaries and we discuss the most recent theoretical predictions for merger rates. Next, we turn to the quasi-equilibrium formalisms that are used to study binaries prior to the merger phase and to generate initial data for fully dynamical simulations. The quasi-equilibrium approximation has played a key role in developing our understanding of the physics of binary coalescence and, in particular, of the orbital instability processes that can drive binaries to merger at the end of their lifetimes. We then turn to the numerical techniques used in dynamical simulations, including relativistic formalisms, (magneto-hydrodynamics, gravitational-wave extraction techniques, and nuclear microphysics treatments. This is followed by a summary of the simulations performed across the field to date, including the most recent results from both fully relativistic and microphysically detailed simulations. Finally, we discuss the likely directions for the field as we transition from the first to the second generation of gravitational-wave interferometers and while supercomputers reach the petascale frontier.

  5. ORBITAL AND PHYSICAL PROPERTIES OF THE σ Ori Aa, Ab, B TRIPLE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Simón-Díaz, S. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Caballero, J. A.; Apellániz, J. Maíz [Centro de Astrobiología (CSIC-INTA), ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Lorenzo, J.; Negueruela, I.; Dorda, R.; Marco, A. [Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Escuela Politécnica Superior, University of Alicante, Apdo. 99, E-03080 Alicante (Spain); Schneider, F. R. N. [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); Barbá, R. H. [Departamento de Física, Universidad de La Serena, Benavente 980, La Serena (Chile); Montes, D. [Departamento Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Pellerin, A. [Department of Physics and Astronomy, State University of New York at Geneseo, 1 College Circle, Geneseo, NY 14454 (United States); Sanchez-Bermudez, J.; Sota, A. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Sódor, Á., E-mail: ssimon@iac.es [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-01121 Budapest (Hungary)

    2015-02-01

    We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the σ Ori Aa, Ab pair. We provided indirect arguments indicating that σ Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while σ Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the σ Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the σ Orionis cluster, the interpretation of the strong X-ray emission detected for σ Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.

  6. Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods

    CERN Document Server

    Abate, C; Karakas, A I; Izzard, R G

    2015-01-01

    AGB stars are responsible for producing a variety of elements, including carbon, nitrogen, and the heavy elements produced in the slow neutron-capture process ($s$-elements). There are many uncertainties involved in modelling the evolution and nucleosynthesis of AGB stars, and this is especially the case at low metallicity, where most of the stars with high enough masses to enter the AGB have evolved to become white dwarfs and can no longer be observed. The stellar population in the Galactic halo is of low mass ($\\lesssim 0.85M_{\\odot}$) and only a few observed stars have evolved beyond the first giant branch. However, we have evidence that low-metallicity AGB stars in binary systems have interacted with their low-mass secondary companions in the past. The aim of this work is to investigate AGB nucleosynthesis at low metallicity by studying the surface abundances of chemically peculiar very metal-poor stars of the halo observed in binary systems. To this end we select a sample of 15 carbon- and $s$-element-en...

  7. Radio Emission and Orbital Motion from the Close-Encounter Star-Brown Dwarf Binary WISE J072003.20-084651.2

    CERN Document Server

    Burgasser, Adam J; Todd, Jacob; Gelino, Christopher R; Hallinan, Gregg; Gagliuffi, Daniella Bardalez

    2015-01-01

    We report the detection of radio emission and orbital motion from the nearby star-brown dwarf binary WISE J072003.20-084651.2AB. Radio observations across the 4.5-6.5 GHz band with the Very Large Array identify at the position of the system quiescent emission with a flux density of 15$\\pm$3 $\\mu$Jy, and a highly-polarized radio source that underwent a 2-3 min burst with peak flux density 300$\\pm$90 $\\mu$Jy. The latter emission is likely a low-level magnetic flare similar to optical flares previously observed for this source. No outbursts were detected in separate narrow-band H$\\alpha$ monitoring observations. We report new high-resolution imaging and spectroscopic observations that confirm the presence of a co-moving T5.5 secondary and provide the first indications of three-dimensional orbital motion. We used these data to revise our estimates for the orbital period (4.1$^{+2.7}_{-1.3}$ yr) and tightly constrain the orbital inclination to be nearly edge-on (93.6\\deg$^{+1.6\\deg}_{-1.4\\deg}$), although robust m...

  8. The spin axes orbital alignment of both stars within the eclipsing binary system V1143Cyg using the Rossiter-McLaughlin effect

    CERN Document Server

    Albrecht, S; Snellen, I; Quirrenbach, Andreas G; Mitchell, D S

    2007-01-01

    Context: The Rossiter-McLaughlin (RM) effect, a rotational effect in eclipsing systems, provides unique insight into the relative orientation of stellar spin axes and orbital axes of eclipsing binary systems. Aims: Our aim is to develop a robust method to analyze the RM effect in an eclipsing system with two nearly equally bright components. This gives access to the orientation of the stellar rotation axes and may shed light on questions of binary formation and evolution. Methods: High-resolution spectra have been obtained both out of eclipse and during the primary and secondary eclipses in the V1143Cyg system, using the high-resolution Hamilton Echelle Spectrograph at the Lick Observatory. The Rossiter-McLaughlin effect is analyzed in two ways: (1) by measuring the shift of the line center of gravity during different phases of the eclipses and (2) by analysis of the line shape change of the rotational broadening function during eclipses. Results: The projected axes of both stars are aligned with the orbital ...

  9. High Resolution Imaging of Very Low Mass Spectral Binaries: Three Resolved Systems and Detection of Orbital Motion in an L/T Transition Binary

    Science.gov (United States)

    Bardalez Gagliuffi, Daniella C.; Gelino, Christopher R.; Burgasser, Adam J.

    2015-11-01

    We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We resolve three systems: 2MASS J1341-3052, SDSS J1511+0607 and SDSS J2052-1609 the first two are resolved for the first time. All three have projected separations Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  10. Evolution of intermediate mass and massive binary stars: physics, mass loss, and rotation

    CERN Document Server

    Vanbeveren, D

    2016-01-01

    In the present review we discuss the past and present status of the interacting OB-type binary frequency. We critically examine the popular idea that Be-stars and supergiant sgB[e] stars are binary evolutionary products. The effects of rotation on stellar evolution in general, stellar population studies in particular, and the link with binaries will be evaluated. Finally a discussion is presented of massive double compact star binary mergers as possible major sites of chemical enrichment of r-process elements and as the origin of recent aLIGO GW events.

  11. Canonical Angles In A Compact Binary Star System With Spinning Components: Approximative Solution Through Next-To-Leading-Order Spin-Orbit Interaction for Circular Orbits

    CERN Document Server

    Tessmer, Manuel; Schäfer, Gerhard

    2013-01-01

    This publication will deal with an explicit determination of the time evolution of the spin orientation axes and the evolution of the orbital phase in the case of circular orbits under next-to-leading order spin-orbit interactions. We modify the method of Schneider and Cui proposed in ["Theoreme \\"uber Bewegungsintegrale und ihre Anwendungen in Bahntheorien", Verlag der Bayerischen Akademie der Wissenschaften, volume 212, 2005.] to iteratively remove oscillatory terms in the equations of motion for different masses that were not present in the case of equal masses. Our smallness parameter is chosen to be the difference of the symmetric mass ratio to the value 1/4. Before the first Lie transformation, the set of conserved quantities consists of the total angular momentum, the amplitudes of the orbital angular momentum and of the spins, $L, S_1,$ and $S_2$. In contrary, the magnitude of the total spin $S=|S_1+S_2|$ is not conserved and we wish to shift its non-conservation to higher orders of the smallness para...

  12. Spin and orbital magnetism in ordered Fe.sub.3+-δ./sub.Si.sub.1-+δ./sub. binary Heusler structures: theory versus experiment

    Czech Academy of Sciences Publication Activity Database

    Zakeri, Kh.; Hashemifar, S.J.; Lindner, J.; Barsukov, I.; Meckenstock, R.; Kratzer, P.; Frait, Zdeněk; Farle, M.

    2008-01-01

    Roč. 77, č. 10 (2008), 104430/1-104430/5. ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100520 Keywords : FeSi Heusler alloys * spin/orbital moments * ferromagnetic resonance * squid Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  13. Astrophysics, cosmology, and fundamental physics with compact binary coalescence and the Einstein Telescope

    International Nuclear Information System (INIS)

    The second-generation interferometric gravitational wave detectors, currently under construction are expected to make their first detections within this decade. This will firmly establish gravitational wave physics as an empirical science, and will open up a new era in astrophysics, cosmology, and fundamental physics. Already with the first detections, we will be able to, among other things, establish the nature of short-hard gamma ray bursts, definitively confirm the existence of black holes, measure the Hubble constant in a completely independent way, and for the first time gain access to the genuinely strong-field dynamics of gravity. Hence, it is time to consider the longer-term future of this new field. The Einstein Telescope (ET) is a concrete conceptual proposal for a third-generation gravitational wave observatory, which will be ∼ 10 times more sensitive in strain than the second-generation detectors. This will give access to sources at cosmological distances, with a correspondingly higher detection rate. We have given an overview of the science case for ET, with a focus on what can be learned from signals emitted by coalescing compact binaries. Third-generation observatories will allow us to map the coalescence rate out to redshifts z ∼ 3, determine the mass functions of neutron stars and black holes, and perform precision measurements of the neutron star equation of state. ET will enable us to study the large-scale structure and evolution of the Universe without recourse to a cosmic distance ladder. Finally, we have discussed how it will allow for high-precision measurements of strong-field, dynamical gravity

  14. The Orbital Solution and Spectral Classification of the High-Mass X-Ray Binary IGR J01054-7253 in the Small Magellanic Cloud

    CERN Document Server

    Townsend, L J; Corbet, R H D; McBride, V A; Hill, A B; Bird, A J; Schurch, M P E; Haberl, F; Sturm, R; Pathak, D; van Soelen, B; Bartlett, E S; Drave, S P; Udalski, A

    2010-01-01

    We present X-ray and optical data on the Be/X-ray binary (BeXRB) pulsar IGR J01054-7253 = SXP11.5 in the Small Magellanic Cloud (SMC). Rossi X-ray Timing Explorer (RXTE) observations of this source in a large X-ray outburst reveal an 11.483 +/- 0.002s pulse period and show both the accretion driven spin-up of the neutron star and the motion of the neutron star around the companion through Doppler shifting of the spin period. Model fits to these data suggest an orbital period of 36.3 +/- 0.4d and Pdot of (4.7 +/- 0.3) x 10^{-10} ss^{-1}. We present an orbital solution for this system, making it one of the best described BeXRB systems in the SMC. The observed pulse period, spin-up and X-ray luminosity of SXP11.5 in this outburst are found to agree with the predictions of neutron star accretion theory. Timing analysis of the long-term optical light curve reveals a periodicity of 36.70 +/- 0.03d, in agreement with the orbital period found from the model fit to the X-ray data. Using blue-end spectroscopic observat...

  15. A numerical investigation of wind accretion in persistent Supergiant X-ray Binaries I - Structure of the flow at the orbital scale

    CERN Document Server

    Mellah, I El

    2016-01-01

    Classical Supergiant X-ray Binaries host a neutron star orbiting a supergiant OB star and display persistent X-ray luminosities of 10$^{35}$ to 10$^{37}$ erg/s. The stellar wind from the massive companion is believed to be the main source of matter accreted by the compact object. With this first paper, we introduce a ballistic model to characterize the structure of the wind at the orbital scale as it accelerates, from the stellar surface to the vicinity of the accretor. Thanks to the parametrization we retained and the numerical pipeline we designed, we can investigate the supersonic flow and the subsequent observables as a function of a reduced set of characteristic numbers and scales. We show that the shape of the permanent flow is entirely determined by the mass ratio, the filling factor, the Eddington factor and the $\\alpha$-force multiplier which drives the stellar wind acceleration. Provided scales such as the orbital period are known, we can trace back the observables to evaluate the mass accretion rat...

  16. Dynamical analyses of the companions orbiting eclipsing binaries II. Z Draconis with four companions close to 6:3:2:1 mean motion resonances

    CERN Document Server

    Yuan, Jinzhao; Selam, Selim O; Gümüş, Damla

    2014-01-01

    All available mid-eclipse times of the short-period eclipsing binary Z Draconis are analysed, and multiple cyclic variations are found. Based on the light-travel time model, we find three companions around Z Draconis, and one or more possible short-period companions. The derived orbital periods suggest that the three outer companions and an inner one are in a near 6:3:2:1 mean-motion resonances. The most outer companion has the minimum mass of $\\sim0.7M_{\\bigodot}$, whereas other companions are M dwarfs. We have studied the stabilities of the companions moving on a series of mutually inclined orbits. The results show that no orbital configurations can survive for 200 yr. We speculate that the instability of the system can be attributed to the uncertainties of the short-period companions, which result from the low-precision mid-eclipse times. Thus, secular CCD observations with much higher precision are needed in the future.

  17. Orbital properties of an unusually low-mass sdB star in a close binary system with a white dwarf

    CERN Document Server

    Silvotti, R; Bloemen, S; Telting, J H; Heber, U; Oreiro, R; Reed, M D; Farris, L E; O'Toole, S J; Lanteri, L; Degroote, P; Hu, H; Baran, A S; Hermes, J J; Althaus, L G; Marsh, T R; Charpinet, S; Li, J; Morris, R L; Sanderfer, D T

    2012-01-01

    We have used 605 days of photometric data from the Kepler spacecraft to study KIC 6614501, a close binary system with an orbital period of 0.15749747(25) days (3.779939 hours), that consists of a low-mass subdwarf B (sdB) star and a white dwarf. As seen in many other similar systems, the gravitational field of the white dwarf produces an ellipsoidal deformation of the sdB which appears in the light curve as a modulation at two times the orbital frequency. The ellipsoidal deformation of the sdB implies that the system has a maximum inclination of \\sim40 degrees, with i \\approx 20\\degrees being the most likely. The orbital radial velocity of the sdB star is high enough to produce a Doppler beaming effect with an amplitude of 432 \\pm 5 ppm, clearly visible in the folded light curve. The photometric amplitude that we obtain, K1 = 85.8 km/s, is \\sim 12 per cent less than the spectroscopic RV amplitude of 97.2 \\pm 2.0 km/s. The discrepancy is due to the photometric contamination from a close object at about 5 arcse...

  18. Spin-orbit coupling in InSb semiconductor nanowires: physical limits for majorana states

    Science.gov (United States)

    Sipahi, Guilherme; de Campos, Tiago; Faria Junior, Paulo E.; Gmitra, Martin; Zutic, Igor; Fabian, Jaroslav

    The search for Majorana fermions is a hot subject nowadays. One of the possibilities for their realization is the use of semiconductor nanowires and p-type superconductors coupled together. Following this path, the first step is the determination of realistic band structures of these wires including spin-orbit effects. To consider the spin-orbit effects, its common to use models that take into account only the first conduction band. Although these reduced models have been successfully used to determine some physical properties, a more realistic description of the spin-orbit coupling between the bands is required to further investigate possible ways to realize the Majorana fermions. In this study we use a state of the art 14 band k.p formalism together with the envelope function approach to determine the band structure of InAs semiconductor nanowires and analyze how the quantum confinement change the coupling between the bands. As a result we have extracted the effective masses and the spin-orbit splitting for a large range of nanowire radial sizes and for several conduction bands that can be used in effective models. FAPESP (No. 2011/19333-4, No. 2012/05618-0 and No. 2013/23393-8), CNPq (No. 246549/2012-2 and No. 149904/2013-4), CAPES(PVE 88881.068174/2014-01) and DFG SFB 689.

  19. Orbital Architectures of Planet-hosting Binaries. I. Forming Five Small Planets in the Truncated Disk of Kepler-444A

    Science.gov (United States)

    Dupuy, Trent J.; Kratter, Kaitlin M.; Kraus, Adam L.; Isaacson, Howard; Mann, Andrew W.; Ireland, Michael J.; Howard, Andrew W.; Huber, Daniel

    2016-01-01

    We present the first results from our Keck program investigating the orbital architectures of planet-hosting multiple star systems. Kepler-444 is a metal-poor triple star system that hosts five sub-Earth-sized planets orbiting the primary star (Kepler-444A), as well as a spatially unresolved pair of M dwarfs (Kepler-444BC) at a projected distance of 1\\buildrel{\\prime\\prime}\\over{.} 8 (66 AU). We combine our Keck/NIRC2 adaptive optics astrometry with multi-epoch Keck/HIRES RVs of all three stars to determine a precise orbit for the BC pair around A, given their empirically constrained masses. We measure minimal astrometric motion (1.0 ± 0.6 mas yr-1, or 0.17 ± 0.10 km s-1), but our RVs reveal significant orbital velocity (1.7 ± 0.2 km s-1) and acceleration (7.8 ± 0.5 m s-1 yr-1). We determine a highly eccentric stellar orbit (e=0.864+/- 0.023) that brings the tight M dwarf pair within {5.0}-1.0+0.9 AU of the planetary system. We validate that the system is dynamically stable in its present configuration via n-body simulations. We find that the A-BC orbit and planetary orbits are likely aligned (98%) given that they both have edge-on orbits and misalignment induces precession of the planets out of transit. We conclude that the stars were likely on their current orbits during the epoch of planet formation, truncating the protoplanetary disk at ≈2 AU. This truncated disk would have been severely depleted of solid material from which to form the total ≈1.5 M⊕ of planets. We thereby strongly constrain the efficiency of the conversion of dust into planets and suggest that the Kepler-444 system is consistent with models that explain the formation of most close-in Kepler planets in more typical, not truncated, disks. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The

  20. Evolution of a ring around the Pluto-Charon binary

    CERN Document Server

    Bromley, B C

    2015-01-01

    We consider the formation of satellites around the Pluto-Charon binary. An early collision between the two partners likely produced the binary and a narrow ring of debris, out of which arose the moons -- Styx, Nix, Kerberos and Hydra. Yet how the satellites emerged from the compact ring is uncertain. Here we show that a particle ring can spread from physical collisions and collective gravitational scattering, similar to migration. Around a binary, these processes take place in the reference frames of `most circular' orbits, akin to circular ones in a Keplerian potential. Ring particles can damp to these orbits, avoiding destructive collisions. Damping and diffusion can also help particles survive dynamical instabilities driven by resonances with the binary. In some situations, particles get trapped near resonances that sweep outward with the tidal evolution of the Pluto-Charon binary. With simple models and numerical experiments, we show how the Pluto-Charon impact ring may have expanded into a broad disk, ou...

  1. Orbital Architectures of Planet-Hosting Binaries: I. Forming Five Small Planets in the Truncated Disk of Kepler-444A

    CERN Document Server

    Dupuy, Trent J; Kraus, Adam L; Isaacson, Howard; Mann, Andrew W; Ireland, Michael J; Howard, Andrew W; Huber, Daniel

    2015-01-01

    We present the first results from our Keck program investigating the orbital architectures of planet-hosting multiple star systems. Kepler-444 is a metal-poor triple star system that hosts five sub-Earth-sized planets orbiting the primary star (Kepler-444A), as well as a spatially unresolved pair of M dwarfs (Kepler-444BC) at a projected distance of 1.8" (66 AU). We combine our Keck/NIRC2 adaptive optics astrometry with multi-epoch Keck/HIRES RVs of all three stars to determine a precise orbit for the BC pair around A, given their empirically constrained masses. We measure minimal astrometric motion ($1.0\\pm0.6$ mas yr$^{-1}$, or $0.17\\pm0.10$ km s$^{-1}$), but our RVs reveal significant orbital velocity ($1.7\\pm0.2$ km s$^{-1}$) and acceleration ($7.8\\pm0.5$ m s$^{-1}$ yr$^{-1}$). We determine a highly eccentric stellar orbit ($e=0.864\\pm0.023$) that brings the tight M dwarf pair within $5.0^{+0.9}_{-1.0}$ AU of the planetary system. We validate that the system is dynamically stable in its present configurat...

  2. Orbital and physical characteristics of meter-scale impactors from airburst observations

    Science.gov (United States)

    Brown, P.; Wiegert, P.; Clark, D.; Tagliaferri, E.

    2016-03-01

    We have analyzed the orbits and ablation characteristics in the atmosphere of 59 Earth-impacting fireballs, produced by meteoroids 1 m in diameter or larger, described here as meter-scale. Using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in strengths of the population of meter-scale impactors at the Earth. We use fireballs producing recovered meteorites and well documented fireballs from ground-based camera networks to calibrate our ablation model interpretation of the observed peak height of luminosity as a function of speed. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. This is in contrast to earlier suggestions by Ceplecha (Ceplecha, Z. [1994]. Astron. Astrophys. 286, 967-970) that the majority of meter-tens of meter sized meteoroids are "… cometary bodies of the weakest known structure". We find a lower limit of ∼10-15% of our objects have a possible cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, also show evidence for weaker than average structure. Two events, Sumava and USG 20131121, have exceptionally high (relative to the remainder of the population) heights of peak brightness. These are physically most consistent with high microporosity objects, though both were on asteroidal-type orbits. We also find three events, including the Oct 8, 2009 airburst near Sulawesi, Indonesia, which display comparatively low heights of peak brightness, consistent with strong monolithic stones or iron meteoroids. Based on orbital similarity, we find a probable connection among several events in our population with the Taurid meteoroid complex; no other major meteoroid streams show probable linkages to the orbits of our meter-scale population. Our impactors cover almost four orders of magnitude in mass, but

  3. Secular Dynamics of S-type Planetary Orbits in Binary Star Systems: Applicability Domains of First- and Second-Order Theories

    CERN Document Server

    Andrade-Ines, Eduardo; Michtchenko, Tatiana; Robutel, Philippe

    2015-01-01

    We analyse the secular dynamics of planets on S-type coplanar orbits in tight binary systems, based on first- and second-order analytical models, and compare their predictions with full N-body simulations. The perturbation parameter adopted for the development of these models depends on the masses of the stars and on the semimajor axis ratio between the planet and the binary. We show that each model has both advantages and limitations. While the first-order analytical model is algebraically simple and easy to implement, it is only applicable in regions of the parameter space where the perturbations are sufficiently small. The second-order model, although more complex, has a larger range of validity and must be taken into account for dynamical studies of some real exoplanetary systems such as $\\gamma$-Cephei and HD 41004A. However, in some extreme cases, neither of these analytical models yields quantitatively correct results, requiring either higher-order theories or direct numerical simulations. Finally, we ...

  4. Orbital and Spin Parameter Variations of Partial Eclipsing Low Mass X-ray Binary X 1822-371

    CERN Document Server

    Chou, Yi; Hu, Chin-Ping; Yang, Ting-Chang; Su, Yi-Hao

    2016-01-01

    We report our measurements for orbital and spin parameters of X 1822-371 using its X-ray partial eclipsing profile and pulsar timing from data collected by the Rossi X-ray Timing Explorer (RXTE). Four more X-ray eclipse times obtained by the RXTE 2011 observations were combined with historical records to trace evolution of orbital period. We found that a cubic ephemeris likely better describes evolution of the X-ray eclipse times during a time span of about 34 years with a marginal second order derivative of $\\ddot{P}_{orb}=(-1.05 \\pm 0.59) \\times 10^{-19}$ s$^{-1}$. Using the pulse arrival time delay technique, the orbital and spin parameters were obtained from RXTE observations from 1998 to 2011. The detected pulse periods show that the neutron star in X 1822-371 is continuously spun-up with a rate of $\\dot{P}_{s}=(-2.6288 \\pm 0.0095) \\times 10^{-12}$ s s$^{-1}$. Evolution of the epoch of the mean longitude $l=\\pi /2$ (i.e. $T_{\\pi / 2}$) gives an orbital period derivative value consistent with that obtaine...

  5. The Mutual Orbit, Mass, and Density of the Large Transneptunian Binary System Varda and Ilmar\\"e

    CERN Document Server

    Grundy, W M; Benecchi, S D; Roe, H G; Noll, K S; Trujillo, C A; Thirouin, A; Stansberry, J A; Barker, E; Levison, H F

    2015-01-01

    From observations by the Hubble Space Telescope, Keck II Telescope, and Gemini North Telescope, we have determined the mutual orbit of the large transneptunian object (174567) Varda and its satellite Ilmar\\"e. These two objects orbit one another in a highly inclined, circular or near-circular orbit with a period of 5.75 days and a semimajor axis of 4810 km. This orbit reveals the system mass to be (2.664 +/- 0.064) x 10^20 kg, slightly greater than the mass of the second most massive main-belt asteroid (4) Vesta. The dynamical mass can in turn be combined with estimates of the surface area of the system from Herschel Space Telescope thermal observations to estimate a bulk density of 1.24 +0.50 -0.35 g cm^-3. Varda and Ilmar\\"e both have colors similar to the combined colors of the system, B-V = 0.886 +/- 0.025 and V-I = 1.156 +/- 0.029.

  6. The basic physics of the binary black hole merger GW150914

    CERN Document Server

    Abbott, B P; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Bejger, M; Bell, A S; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Broida, J E; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Brunett, S; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Bustillo, J Calder'on; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Diaz, J Casanueva; Casentini, C; Caudill, S; Cavagli`a, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Baiardi, L Cerboni; Cerretani, G; Cesarini, E; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, H Y; Chen, Y; Cheng, C; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C G; Cominsky, L; Constancio, M; Conte, A; Conti, L; Cook, D; Corbitt, T R; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J -P; Countryman, S T; Couvares, P; Cowan, E E; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Cripe, J; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Canton, T Dal; Danilishin, S L; D'Antonio, S; Danzmann, K; Darman, N S; Dasgupta, A; Costa, C F Da Silva; Dattilo, V; Dave, I; Davier, M; Davies, G S; Daw, E J; Day, R; De, S; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Del'eglise, S; Del Pozzo, W; Denker, T; Dent, T; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Devine, R C; Dhurandhar, S; D'iaz, M C; Di Fiore, L; Di Giovanni, M; Di Girolamo, T; Di Lieto, A; Di Pace, S; Di Palma, I; Di Virgilio, A; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Ducrot, M; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H -B; Ehrens, P; Eichholz, J; Eikenberry, S S; Engels, W; Essick, R C; Etzel, T; Evans, M; Evans, T M; Everett, R; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Fenyvesi, E; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Fiori, I; Fiorucci, D; Fisher, R P; Flaminio, R; Fletcher, M; Fournier, J -D; Frasca, S; Frasconi, F; Frei, Z; Freise, A; Frey, R; Frey, V; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H A G; Gair, J R; Gammaitoni, L; Gaonkar, S G; Garufi, F; Gaur, G; Gehrels, N; Gemme, G; Geng, P; Genin, E; Gennai, A; George, J; Gergely, L; Germain, V; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Goetz, E; Goetz, R; Gondan, L; Gonz'alez, G; Castro, J M Gonzalez; Gopakumar, A; Gordon, N A; Gorodetsky, M L; Gossan, S E; Gosselin, M; Gouaty, R; Grado, A; Graef, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greco, G; Green, A C; Groot, P; Grote, H; Grunewald, S; Guidi, G M; Guo, X; Gupta, A; Gupta, M K; Gushwa, K E; Gustafson, E K; Gustafson, R; Hacker, J J; Hall, B R; Hall, E D; Hammond, G; Haney, M; Hanke, M M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M J; Hartman, M T; Haster, C -J; Haughian, K; Heidmann, A; Heintze, M C; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Hennig, J; Henry, J; Heptonstall, A W; Heurs, M; Hild, S; Hoak, D; Hofman, D; Holt, K; Holz, D E; Hopkins, P; Hough, J; Houston, E A; Howell, E J; Hu, Y M; Huang, S; Huerta, E A; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Indik, N; Ingram, D R; Inta, R; Isa, H N; Isac, J -M; Isi, M; Isogai, T; Iyer, B R; Izumi, K; Jacqmin, T; Jang, H; Jani, K; Jaranowski, P; Jawahar, S; Jian, L; Jim'enez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalaghatgi, C V; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Kapadia, S J; Karki, S; Karvinen, K S; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, S; Kaur, T; Kawabe, K; K'ef'elian, F; Kehl, M S; Keitel, D; Kelley, D B; Kells, W; Kennedy, R; Key, J S; Khalili, F Y; Khan, I; Khan, S; Khan, Z; Khazanov, E A; Kijbunchoo, N; Kim, Chi-Woong; Kim, Chunglee; Kim, J; Kim, K; Kim, N; Kim, W; Kim, Y -M; Kimbrell, S J; King, E J; King, P J; Kissel, J S; Klein, B; Kleybolte, L; Klimenko, S; Koehlenbeck, S M; Koley, S; Kondrashov, V; Kontos, A; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Kr'olak, A; Krueger, C; Kuehn, G; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Lackey, B D; Landry, M; Lange, J; Lantz, B; Lasky, P D; Laxen, M; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Lee, K; Lenon, A; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Lewis, J B; Li, T G F; Libson, A; Littenberg, T B; Lockerbie, N A; Lombardi, A L; London, L T; Lord, J E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J D; L"uck, H; Lundgren, A P; Lynch, R; Ma, Y; Machenschalk, B; MacInnis, M; Macleod, D M; Magana-Sandoval, F; Zertuche, L Magana; Magee, R M; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandic, V; Mangano, V; Mansell, G L; Manske, M; Mantovani, M; Marchesoni, F; Marion, F; M'arka, S; M'arka, Z; Markosyan, A S; Maros, E; Martelli, F; Martellini, L; Martin, I W; Martynov, D V; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Masso-Reid, M; Mastrogiovanni, S; Matichard, F; Matone, L; Mavalvala, N; Mazumder, N; McCarthy, R; McClelland, D E; McCormick, S; McGuire, S C; McIntyre, G; McIver, J; McManus, D J; McRae, T; Meacher, D; Meadors, G D; Meidam, J; Melatos, A; Mendell, G; Mercer, R A; Merilh, E L; Merzougui, M; Meshkov, S; Messenger, C; Messick, C; Metzdorff, R; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, A; Miller, B B; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moggi, A; Mohan, M; Mohapatra, S R P; Montani, M; Moore, B C; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, N; Mullavey, A; Munch, J; Murphy, D J; Murray, P G; Mytidis, A; Nardecchia, I; Naticchioni, L; Nayak, R K; Nedkova, K; Nelemans, G; Nelson, T J N; Neri, M; Neunzert, A; Newton, G; Nguyen, T T; Nielsen, A B; Nissanke, S; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Oberling, J; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Paris, H R; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patricelli, B; Patrick, Z; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Perreca, A; Perri, L M; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poe, M; Poggiani, R; Popolizio, P; Post, A; Powell, J; Prasad, J; Pratt, J; Predoi, V; Prestegard, T; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; P"urrer, M; Qi, H; Qin, J; Qiu, S; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rajan, C; Rakhmanov, M; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Read, J; Reed, C M; Regimbau, T; Rei, L; Reid, S; Rew, H; Reyes, S D; Ricci, F; Riles, K; Rizzo, M; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romanov, G; Romie, J H; Rosi'nska, D; Rowan, S; R"udiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sanchez, E J; Sandberg, V; Sandeen, B; Sanders, J R; Sassolas, B; Saulson, P R; Sauter, O E S; Savage, R L; Sawadsky, A; Schale, P; Schilling, R; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Sch"onbeck, A; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Setyawati, Y; Shaddock, D A; Shaffer, T; Shahriar, M S; Shaltev, M; Shapiro, B; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, A; Singer, L P; Singh, A; Singh, R; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, J R; Smith, N D; Smith, R J E; Son, E J; Sorazu, B; Sorrentino, F; Souradeep, T; Srivastava, A K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strauss, N A; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Sutton, P J; Swinkels, B L; Szczepa'nczyk, M J; Tacca, M; Talukder, D; Tanner, D B; T'apai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Theeg, T; Thirugnanasambandam, M P; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tomlinson, C; Tonelli, M; Tornasi, Z; Torres, C V; Torrie, C I; T"oyr"a, D; Travasso, F; Traylor, G; Trifir`o, D; Tringali, M C; Trozzo, L; Tse, M; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; van Bakel, N; van Beuzekom, M; Brand, J F J van den; Broeck, C Van Den; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Vass, S; Vas'uth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Vicer'e, A; Vinciguerra, S; Vine, D J; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D V; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wessels, P; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Woehler, J; Worden, J; Wright, J L; Wu, D S; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yu, H; Yvert, M; zny, A Zadro; Zangrando, L; Zanolin, M; Zendri, J -P; Zevin, M; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J

    2016-01-01

    The first direct gravitational-wave detection was made by the Advanced Laser Interferometer Gravitational Wave Observatory on September 14, 2015. The GW150914 signal was strong enough to be apparent, without using any waveform model, in the filtered detector strain data. Here those features of the signal visible in these data are used, along with only such concepts from Newtonian and General Relativity as are accessible to anyone with a general physics background. The simple analysis presented here is consistent with the fully general-relativistic analyses published elsewhere, in showing that the signal was produced by the inspiral and subsequent merger of two black holes. The black holes were each of approximately 35 Msun, still orbited each other as close as 350 km apart and subsequently merged to form a single black hole. Similar reasoning, directly from the data, is used to roughly estimate how far these black holes were from the Earth, and the energy that they radiated in gravitational waves.

  7. The Physical Nature and Orbital Behavior of the Eclipsing System DK Cygni

    CERN Document Server

    Lee, Jae Woo; Park, Jang-Ho; Wolf, Marek

    2015-01-01

    New CCD photometry is presented for the hot overcontact binary DK Cyg, together with reasonable explanations for the light and period variations. Historical light and velocity curves from 1962 to 2012 were simultaneously analyzed with the Wilson-Devinney (W-D) synthesis code. The brightness disturbances were satisfactorily modeled by applying a magnetic cool spot on the primary star. Based on 261 times of minimum light including 116 new timings and spanning more than 87 yrs, a period study reveals that the orbital period has varied due to a periodic oscillation superposed on an upward parabola. The period and semi-amplitude of the modulation are about 78.1 yrs and 0.0037 d, respectively. This detail is interpreted as a light-travel-time effect due to a circumbinary companion with a minimum mass of $M_3 =0.065 $M_\\odot$, within the theoretical limit of $\\sim$0.07 M$_\\odot$ for a brown dwarf star. The observed period increase at a fractional rate of $+$2.74 $\\times $10$^{-10}$ is in excellent agreement with tha...

  8. The Physical Nature and Orbital Behavior of the Eclipsing System DK Cygni

    Science.gov (United States)

    Lee, Jae Woo; Youn, Jae-Hyuck; Park, Jang-Ho; Wolf, Marek

    2015-06-01

    New CCD photometry is presented for the hot overcontact binary DK Cyg together with reasonable explanations for the light and period variations. Historical light and velocity curves from 1962 to 2012 were simultaneously analyzed with the Wilson-Devinney (W-D) synthesis code. The brightness disturbances were satisfactorily modeled by applying a magnetic cool spot on the primary star. Based on 261 times of minimum light that include 116 new timings and span more than 87 years, a period study reveals that the orbital period has varied due to a periodic oscillation superimposed on an upward parabola. The period and semi-amplitude of the modulation are about 78.1 years and 0.0037 days, respectively. This detail is interpreted as a light-travel-time effect due to a circumbinary companion with a minimum mass of M3 = 0.065 M⊙, within the theoretical limit of ˜0.07 M⊙ for a brown dwarf star. The observed period increase at a fractional rate of +2.74 × 10-10 is in excellent agreement with that calculated from our W-D synthesis. Mass transfer from the secondary to the primary component is mainly responsible for the secular period change. We examined the evolutionary status of the DK Cyg system from the absolute dimensions.

  9. Orbital and physical properties of planets and their hosts: new insights on planet formation and evolution

    OpenAIRE

    Adibekyan, V. Zh.; Figueira, P.; Santos, N. C.; Mortier, A.; Mordasini, C; Mena, E. Delgado; Sousa, S. G.; Correia, A. C. M.; Israelian, G.; Oshagh, M.

    2013-01-01

    We explore the relations between physical and orbital properties of planets and properties of their host stars to identify the main observable signatures of the formation and evolution processes of planetary systems. We use a large sample of FGK dwarf planet hosts with stellar parameters derived in a homogeneous way from the SWEET-Cat database to study the relation between stellar metallicity and position of planets in the period-mass diagram. In the second part we use all the RV-detected pla...

  10. Orbital and Physical Characteristics of Meter-scale Impactors from Airburst Observations

    CERN Document Server

    Brown, P; Clark, D; Tagliaferri, E

    2015-01-01

    We have analysed the orbits and ablation characteristics in the atmosphere of 59 earth-impacting fireballs, produced by meteoroids one meter in diameter or larger, described here as meter-scale. Using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in strengths of the population of meter-scale impactors at the Earth. We use fireballs producing recovered meteorites and well documented fireballs from ground-based camera networks to calibrate our ablation model interpretation of the observed peak height of luminosity as a function of speed. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. We find a lower limit of ~10-15% of our objects have a possible cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, also show evidence for weaker than average structure. Two ...

  11. Dynamical Masses of Young M Dwarfs. I. Masses and Orbital Parameters of GJ 3305 AB, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri

    CERN Document Server

    Montet, Benjamin T; Shkolnik, Evgenya L; Deck, Katherine M; Wang, Ji; Horch, Elliott P; Liu, Michael C; Hillenbrand, Lynne A; Kraus, Adam L; Charbonneau, David

    2015-01-01

    We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements of the GJ 3305 AB system, a young (~20 Myr) M+M binary (unresolved spectral type M0) member of the beta Pictoris moving group comoving with the imaged exoplanet host 51 Eri. We measure a total system mass of 1.10 \\pm 0.04 M_sun, a period of 29.16 \\pm 0.65$ yr, a semimajor axis of 9.80 \\pm 0.15 AU, and an eccentricity of 0.19 \\pm 0.02. The primary component has a dynamical mass of 0.65 \\pm 0.05 M_sun and the secondary has a mass of 0.44 \\pm 0.05 M_sun. The recently updated BHAC15 models are consistent with the masses of both stars to within 1.5 sigma. Given the observed masses the models predict an age of the GJ 3305 AB system of 28 +15/-6 Myr. Based on the the observed system architecture and our dynamical mass measurement, it is unlikely that the orbit of 51 Eri b has been significantly alter...

  12. Three ways to solve the orbit of KIC11558725: a 10 day beaming sdB+WD binary with a pulsating subdwarf

    CERN Document Server

    Telting, J H; Baran, A S; Bloemen, S; Reed, M D; Oreiro, R; Farris, L; Ottosen, T A; Aerts, C; Kawaler, S D; Heber, U; Prins, S; Green, E M; Kalomeni, B; O'Toole, S J; Mullally, F; Sanderfer, D T; Smith, J C; Kjeldsen, H

    2012-01-01

    The recently discovered subdwarf B (sdB) pulsator KIC11558725 features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods, and is a promising target for a seismic study aiming to constrain the internal structure of this star, and of sdB stars in general. We have obtained ground-based spectroscopic Balmer-line radial-velocity measurements of KIC11558725, spanning the 2010 and 2011 observing seasons. From these data we have discovered that KIC11558725 is a binary with period P=10.05 d, and that the radial-velocity amplitude of the sdB star is 58 km/s. Consequently the companion of the sdB star has a minimum mass of 0.63 M\\odot, and is therefore most likely an unseen white dwarf. We analyse the near-continuous 2010-2011 Kepler light curve to reveal orbital Doppler-beaming light variations at the 238 ppm level, which is consistent with the observed spectroscopic orbital radial-velocity amplitude of the subdwarf. We use the strongest 70 pulsation frequencies in the Kepler light cur...

  13. Orbital solution and evolutionary state for the eclipsing binary 1SWASP J080150.03+471433.8

    CERN Document Server

    Darwish, M S; Nouh, M I; Saad, S M; Hamdy, M A; Beheary, M M; Gadallah, K; Zaid, I

    2016-01-01

    We present an orbital solution study for the newly discovered system 1SWASP J080150.03+471433.8 by means of new CCD observations in VRI bands. Our observations were carried out on 25 Feb. 2013 using the Kottamia optical telescope at NRIAG, Egypt. 12 new times of minima were estimated and the observed light curves were analysed using the Wilson-Devinney code. The accepted orbital solution reveals that the primary component of is more massive and hotter than the secondary one by about 280K. The system is an over-contact one with fillout ratio ~ 29% and is located at a distance of 195 Pc. The evolutionary status of the system is investigated by means of stellar models and empirical data.

  14. Gravitational waves from spinning eccentric binaries

    CERN Document Server

    Csizmadia, Péter; Rácz, István; Vasúth, Mátyás

    2012-01-01

    This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity. In addition, by investigating the validity of the energy balance relat...

  15. Investigating fundamental physics and space environment with a dedicated Earth-orbiting spacecraft

    Science.gov (United States)

    Peron, Roberto

    The near-Earth environment is a place of first choice for performing fundamental physics experiments, given its proximity to Earth and at the same time being relatively quiet dynamically for particular orbital arrangements. This environment also sees a rich phenomenology for what concerns gravitation. In fact, the general theory of relativity is an incredibly accurate description of gravitational phenomenology. However, its overall validity is being questioned by the theories that aim at reconciling it with the microscopic domain. Challenges come also from the ‘mysteries’ of Dark Matter and Dark Energy, though mainly at scales from the galactic up to the cosmological. It is therefore important to precisely test the consequences of the theory -- as well as those of competing ones -- at all the accessible scales. At the same time, the development of high-precision experimental space techniques, which are needed for tests in fundamental physics, opens the way to complementary applications. The growth of the (man-made) orbital debris population is creating problems to the future development of space. The year 2009 witnessed the first accidental collision between two satellites in orbit (Iridium and Cosmos) that led to the creation of more debris. International and national agencies are intervening by issuing and/or adopting guidelines to mitigate the growth of orbital debris. A central tenet of these guidelines requires a presence in space shorter than 25 years to satellites in low Earth orbit (LEO) after the conclusion of their operational lives. However, the determination of the natural lifetime of a satellite in LEO is very uncertain due to a large extent to the short-term and long-term variability of the atmospheric density in LEO and the comparatively low-accuracy of atmospheric density models. Many satellites orbiting in the 500-1200 km region with circular or elliptical orbits will be hard pressed to establish before flight whether or not they meet the 25

  16. Precise Orbit Determination of LAGEOS satellites: results on fundamental physics and perspectives

    Science.gov (United States)

    Peron, Roberto; Lucchesi, David

    2012-07-01

    The LAGEOS satellites, launched for geodynamics and geophysics purposes, are offering also an outstanding test bench to fundamental physics. Indeed, their physical characteristics, as well as those of their orbits, and the availability of high--quality tracking data provided by the International Laser Ranging Service, allow for precise tests of gravitational theories. In this talk recent work on data analysis will be presented. A fairly large amount of LAGEOS and LAGEOS II Satellite Laser Ranging data has been analyzed with NASA/GSFC Geodyn II software, using a set of dedicated models for satellite dynamics, and the related post--fit residuals have been analyzed. In particular, general relativistic effects leave peculiar imprint on nodal longitude, argument of perigee and inclination behaviour, which have been used to obtain precise estimates of the related parameters. The most precise --- as today --- estimate of the effects on argument of perigee has been obtained, providing a direct measurement of the relativistic ``Schwarzschild'' precession in the field of the Earth. At the same time the constraints on a non--Newtonian (i.e. Yukawa--type) gravitational dynamics have been improved. The measurement error budget will be discussed, emphasizing the role of gravitational and, especially, of non--gravitational forces modeling on the overall precise orbit determination quality, as well as on future new measurements and constraints of the gravitational interaction.

  17. Formation and Stellar Spin-Orbit Misalignment of Hot Jupiters from Lidov-Kozai Oscillations in Stellar Binaries

    CERN Document Server

    Anderson, Kassandra R; Lai, Dong

    2015-01-01

    Observed hot Jupiter (HJ) systems exhibit a wide range of stellar spin-orbit misalignment angles. The origin of these HJs remains unclear. This paper investigates the inward migration of giant planets due to Lidov-Kozai (LK) oscillations induced by a distant (100-1000 AU) stellar companion. We conduct a large population synthesis study, including the octupole gravitational potential from the stellar companion, mutual precession of the host stellar spin axis and planet orbital axis, tidal dissipation in the planet, and stellar spin-down in the host star due to magnetic braking. We consider a range of planet masses ($0.3-5\\,M_J$) and initial semi-major axes ($1-5$AU), different properties for the host star, and varying tidal dissipation strengths. The fraction of systems that result in HJs depends on planet mass and stellar type, with $f_{\\rm HJ} = 1-4\\%$ (depending on tidal dissipation strength) for $M_p=1\\,M_J$, and larger (up to $8\\%$) for more massive planets. The production efficiency of "hot Saturns" ($M_...

  18. [Viscoelastic behaviour of inlay waxes. (Part 2) Physical and dynamic viscoelastic properties for binary mixtures of waxes (author's transl)].

    Science.gov (United States)

    Katakura, N

    1981-01-01

    Binary mixtures of waxes added carnauba wax, beeswax or dammar to paraffin were investigated by measurements of X-ray diffraction, dilatometry, differential thermal analysis and dynamic viscoelasticity. The relationships between the viscoelastic behaviour and the physical properties of these waxes were discussed. Additions of carnauba wax to paraffin changed drastically viscoelastic properties of paraffin, that is, increased the dynamic modulus, G', and decreased the loss tangent, tan delta, in the region of higher temperatures including the crystal transition temperature region of paraffin. The possible explanation for this change of viscoelastic properties is that the presence of crystals of carnauba wax composed of longer chain molecules than that of paraffin rises interfacial interaction. The temperature dependence of viscoelastic properties for binary mixtures of paraffin and beeswax was approximately the same as that of paraffin. This is because paraffin and beeswax may form a sort of homogeneous phases. Additions of dammar to paraffin increased the elasticity of paraffin in the region of lower temperatures, but did not effected to change of G' and tan delta in the region of higher temperatures. Another effect of additions of dammar was to lower the thermal expansion of binary mixtures. PMID:6943233

  19. Dynamics and Habitability in Binary Star Systems

    CERN Document Server

    Eggl, Siegfried; Pilat-Lohinger, Elke

    2014-01-01

    Determining planetary habitability is a complex matter, as the interplay between a planet's physical and atmospheric properties with stellar insolation has to be studied in a self consistent manner. Standardized atmospheric models for Earth-like planets exist and are commonly accepted as a reference for estimates of Habitable Zones. In order to define Habitable Zone boundaries, circular orbital configurations around main sequence stars are generally assumed. In gravitationally interacting multibody systems, such as double stars, however, planetary orbits are forcibly becoming non circular with time. Especially in binary star systems even relatively small changes in a planet's orbit can have a large impact on habitability. Hence, we argue that a minimum model for calculating Habitable Zones in binary star systems has to include dynamical interactions.

  20. Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cyg

    CERN Document Server

    Harmanec, P; Wolf, M; Božić, H; Guinan, E F; Kang, Y W; Mayer, P; McCook, G P; Nemravová, J; Yang, S; Šlechta, M; Ruždjak, D; Sudar, D; Svoboda, P

    2014-01-01

    Thanks to its long and rich observational history and rapid apsidal motion, the massive eclipsing binary Y Cyg represents one of the cornestones to critical tests of stellar evolution theory for massive stars. Yet, the determination of the basic physical properties is less accurate than it could be given the existing number of spectral and photometric observations. Our goal is to analyze all these data simultaneously with the new dedicated series of our own spectral and photometric observations from observatories widely separated in longitude. We obtained new series of UBV observations at three observatories separated in local time to obtain complete light curves of Y Cyg for its orbital period close to 3 days. This new photometry was reduced and carefully transformed to the standard UBV system using the HEC22 program. We also obtained new series of red spectra secured at two observatories and re-analyzed earlier obtained blue electronic spectra. Our analyses provide the most accurate so far published value o...

  1. Binary Planets

    Science.gov (United States)

    Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

    2014-11-01

    Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

  2. Phase diagram and collective excitations in an excitonic insulator from an orbital physics viewpoint

    Science.gov (United States)

    Nasu, Joji; Watanabe, Tsutomu; Naka, Makoto; Ishihara, Sumio

    2016-05-01

    An excitonic-insulating system is studied from a viewpoint of the orbital physics in strongly correlated electron systems. An effective model Hamiltonian for low-energy electronic states is derived from the two-orbital Hubbard model with a finite-energy difference corresponding to the crystalline-field splitting. The effective model is represented by the spin operators and the pseudospin operators for the spin-state degrees of freedom. The ground-state phase diagram is analyzed by the mean-field approximation. In addition to the low-spin state and high-spin state phases, two kinds of the excitonic-insulating phases emerge as a consequence of the competition between the crystalline-field effect and the Hund coupling. Transitions to the excitonic phases are classified to an Ising-type transition resulted from a spontaneous breaking of the Z2 symmetry. Magnetic structures in the two excitonic-insulating phases are different from each other: an antiferromagnetic order and a spin nematic order. Collective excitations in each phase are examined using the generalized spin-wave approximation. Characteristics in the Goldstone modes in the excitonic-insulating phases are studied through the calculations of the dynamical correlation functions for the spins and pseudospin operators. Both the transverse and longitudinal spin excitation modes are active in the two excitonic-insulating phases in contrast to the low-spin state and high-spin state phases. Relationships of the present results to the perovskite cobalt oxides are discussed.

  3. Improved basic physical properties of the Oe-star binary V1007 Sco

    Czech Academy of Sciences Publication Activity Database

    Mayer, P.; Harmanec, Petr; Lorenz, R.; Drechsel, H.; Eenens, P.; Corral, L. J.; Morrell, N.

    Dordrecht : Kluwer, 2001 - (Vanbeveren, D.), s. 567-569 - (Astrophysics and space science library.. 264). [Influence of binaries on stellar population studies. Brusel (BE), 21.08.2000-25.08.2000] R&D Projects: GA MŠk ME 402 Institutional research plan: CEZ:AV0Z1003909 Keywords : hot stars * masses and radii * apsidal motion Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  4. Thermo Physical Properties for Binary Mixture of Dimethylsulfoxide and Isopropylbenzene at Various Temperatures

    OpenAIRE

    Maninder Kumar; V. K. Rattan

    2013-01-01

    Density, refractive index, speed of sound, and viscosity have been measured of binary mixture dimethylsulfoxide (DMSO) + isopropylbenzene (CUMENE) over the whole composition range at 298.15, 303.15, 308.15, and 313.15 K and atmospheric pressure. From these experimental measurements the excess molar volume, deviations in viscosity, molar refractivity, speed of sound, and isentropic compressibility have been calculated. These deviations have been correlated by a polynomial Redlich-Kister equati...

  5. Dynamical Masses of Young M Dwarfs: Masses and Orbital Parameters of GJ 3305 AB, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri

    Science.gov (United States)

    Montet, Benjamin T.; Bowler, Brendan P.; Shkolnik, Evgenya L.; Deck, Katherine M.; Wang, Ji; Horch, Elliott P.; Liu, Michael C.; Hillenbrand, Lynne A.; Kraus, Adam L.; Charbonneau, David

    2015-11-01

    We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements of the GJ 3305 AB system, a young (∼20 Myr) M+M binary (unresolved spectral type M0) member of the β Pictoris moving group comoving with the imaged exoplanet host 51 Eri. We measure a total system mass of 1.11 ± 0.04 {M}ȯ , a period of 29.03 ± 0.50 year, a semimajor axis of 9.78 ± 0.14 AU, and an eccentricity of 0.19 ± 0.02. The primary component has a dynamical mass of 0.67 ± 0.05 {M}ȯ and the secondary has a mass of 0.44 ± 0.05 {M}ȯ . The recently updated BHAC15 models are consistent with the masses of both stars to within 1.5σ . Given the observed masses the models predict an age of the GJ 3305 AB system of 37 ± 9 Myr. Based on the observed system architecture and our dynamical mass measurement, it is unlikely that the orbit of 51 Eri b has been significantly altered by the Kozai–Lidov mechanism. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  6. Dynamical Masses of Young M Dwarfs: Masses and Orbital Parameters of GJ 3305 AB, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri

    Science.gov (United States)

    Montet, Benjamin T.; Bowler, Brendan P.; Shkolnik, Evgenya L.; Deck, Katherine M.; Wang, Ji; Horch, Elliott P.; Liu, Michael C.; Hillenbrand, Lynne A.; Kraus, Adam L.; Charbonneau, David

    2015-11-01

    We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements of the GJ 3305 AB system, a young (˜20 Myr) M+M binary (unresolved spectral type M0) member of the β Pictoris moving group comoving with the imaged exoplanet host 51 Eri. We measure a total system mass of 1.11 ± 0.04 {M}⊙ , a period of 29.03 ± 0.50 year, a semimajor axis of 9.78 ± 0.14 AU, and an eccentricity of 0.19 ± 0.02. The primary component has a dynamical mass of 0.67 ± 0.05 {M}⊙ and the secondary has a mass of 0.44 ± 0.05 {M}⊙ . The recently updated BHAC15 models are consistent with the masses of both stars to within 1.5σ . Given the observed masses the models predict an age of the GJ 3305 AB system of 37 ± 9 Myr. Based on the observed system architecture and our dynamical mass measurement, it is unlikely that the orbit of 51 Eri b has been significantly altered by the Kozai-Lidov mechanism. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  7. PHOTOMETRIC AND SPECTROSCOPIC STUDIES OF MASSIVE BINARIES IN THE LARGE MAGELLANIC CLOUD. I. INTRODUCTION AND ORBITS FOR TWO DETACHED SYSTEMS: EVIDENCE FOR A MASS DISCREPANCY?

    Energy Technology Data Exchange (ETDEWEB)

    Massey, Philip; Neugent, Kathryn F. [Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 (United States); Morrell, Nidia I. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Penny, Laura R. [Department of Physics and Astronomy, The College of Charleston, Charleston, SC 29424 (United States); DeGioia-Eastwood, Kathleen [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011-6010 (United States); Gies, Douglas R., E-mail: phil.massey@lowell.edu, E-mail: kneugent@lowell.edu, E-mail: nmorrell@lco.cl, E-mail: pennyl@cofc.edu, E-mail: kathy.eastwood@nau.edu, E-mail: gies@chara.gsu.edu [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 4106, Atlanta, GA 30302 (United States)

    2012-04-01

    The stellar mass-luminosity relation is poorly constrained by observations for high-mass stars. We describe our program to find eclipsing massive binaries in the Magellanic Clouds using photometry of regions rich in massive stars, and our spectroscopic follow-up to obtain radial velocities and orbits. Our photometric campaign identified 48 early-type periodic variables, of which only 15 (31%) were found as part of the microlensing surveys. Spectroscopy is now complete for 17 of these systems, and in this paper we present analysis of the first two, LMC 172231 and ST2-28, simple detached systems of late-type O dwarfs of relatively modest masses. Our orbit analysis yields very precise masses ({approx}2%), and we use tomography to separate the components and determine effective temperatures by model fitting, necessary for determining accurate (0.05-0.07 dex) bolometric luminosities in combination with the light-curve analysis. Our approach allows more precise comparisons with evolutionary theory than previously possible. To our considerable surprise, we find a small, but significant, systematic discrepancy: all of the stars are slightly undermassive, by typically 11% (or overluminous by 0.2 dex) compared with that predicted by the evolutionary models. We examine our approach for systematic problems, but find no satisfactory explanation. The discrepancy is in the same sense as the long-discussed and elusive discrepancy between the masses measured from stellar atmosphere analysis with the stellar evolutionary models, and might suggest that either increased rotation or convective overshooting is needed in the models. Additional systems will be discussed in future papers of this series, and will hopefully confirm or refute this trend.

  8. KOI-3278: a self-lensing binary star system.

    Science.gov (United States)

    Kruse, Ethan; Agol, Eric

    2014-04-18

    Over 40% of Sun-like stars are bound in binary or multistar systems. Stellar remnants in edge-on binary systems can gravitationally magnify their companions, as predicted 40 years ago. By using data from the Kepler spacecraft, we report the detection of such a "self-lensing" system, in which a 5-hour pulse of 0.1% amplitude occurs every orbital period. The white dwarf stellar remnant and its Sun-like companion orbit one another every 88.18 days, a long period for a white dwarf-eclipsing binary. By modeling the pulse as gravitational magnification (microlensing) along with Kepler's laws and stellar models, we constrain the mass of the white dwarf to be ~63% of the mass of our Sun. Further study of this system, and any others discovered like it, will help to constrain the physics of white dwarfs and binary star evolution. PMID:24744369

  9. KOI-3278: A Self-Lensing Binary Star System

    CERN Document Server

    Kruse, Ethan

    2014-01-01

    Over 40% of Sun-like stars are bound in binary or multistar systems. Stellar remnants in edge-on binary systems can gravitationally magnify their companions, as predicted 40 years ago. By using data from the Kepler spacecraft, we report the detection of such a "self-lensing" system, in which a 5-hour pulse of 0.1% amplitude occurs every orbital period. The white dwarf stellar remnant and its Sun-like companion orbit one another every 88.18 days, a long period for a white dwarf-eclipsing binary. By modeling the pulse as gravitational magnification (microlensing) along with Kepler's laws and stellar models, we constrain the mass of the white dwarf to be ~63% of the mass of our Sun. Further study of this system, and any others discovered like it, will help to constrain the physics of white dwarfs and binary star evolution.

  10. Three ways to solve the orbit of KIC 11 558 725: a 10-day beaming sdB+WD binary with a pulsating subdwarf

    Science.gov (United States)

    Telting, J. H.; Østensen, R. H.; Baran, A. S.; Bloemen, S.; Reed, M. D.; Oreiro, R.; Farris, L.; Ottosen, T. A.; Aerts, C.; Kawaler, S. D.; Heber, U.; Prins, S.; Green, E. M.; Kalomeni, B.; O'Toole, S. J.; Mullally, F.; Sanderfer, D. T.; Smith, J. C.; Kjeldsen, H.

    2012-08-01

    The recently discovered subdwarf B (sdB) pulsator KIC 11 558 725 is one of the 16 pulsating sdB stars detected in the Kepler field. It features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods. This makes it a promising target for a seismic study aiming to constrain the internal structure of this star, and of sdB stars ingeneral. We have obtained ground-based spectroscopic radial-velocity measurements of KIC 11 558 725 based on low-resolution spectra in the Balmer-line region, spanning the 2010 and 2011 observing seasons. From these data we have discovered that KIC 11 558 725 is a binary with period P = 10.05 d, and that the radial-velocity amplitude of the sdB star is 58 km s-1. Consequently the companion of the sdB star has a minimum mass of 0.63 M⊙, and is therefore most likely an unseen white dwarf. We analyse the near-continuous 2010-2011 Kepler light curve to reveal the orbital Doppler-beaming effect, giving rise to light variations at the 238 ppm level, which is consistent with the observed spectroscopic orbital radial-velocity amplitude of the subdwarf. We use the strongest 70 pulsation frequencies in the Kepler light curve of the subdwarf as clocks to derive a third consistent measurement of the orbital radial-velocity amplitude, from the orbital light-travel delay. The orbital radius asdBsini = 11.5 R⊙ gives rise to a light-travel time delay of 53.6 s, which causes aliasing and lowers the amplitudes of the shortest pulsation frequencies, unless the effect is corrected for. We use our high signal-to-noise average spectra to study the atmospheric parameters of the sdB star, deriving Teff = 27 910 K andlog g = 5.41 dex, and find that carbon, nitrogen and oxygen are underabundant relative to the solar mixture. Furthermore, we analyse the Kepler light curve for its pulsational content and extract more than 160 significant frequencies.We investigate the pulsation frequencies for expected period spacings and rotational

  11. Binary Minor Planets V9.0

    Science.gov (United States)

    Johnston, W. R.

    2016-07-01

    The data set lists orbital and physical properties for well-observed or suspected binary/multiple minor planets including the Pluto system, compiled from the published literature as inspired by Richardson and Walsh (2006) and similar reviews (Merline et al., 2003; Noll, 2006; Pravec et al., 2006; Pravec and Harris, 2007; Descamps and Marchis, 2008; Noll et al., 2008; Walsh, 2009). In total 297 companions in 282 systems are included. Data are presented in three tables: one for orbital and physical properties; one for companion designations, discovery information, and reference codes for data values; and one giving full references for each reference code. This data set is complete for binary/multiple components reported through 31 March 2016.

  12. Physical compatibility of binary and ternary mixtures of morphine and methadone with other drugs for parenteral administration in palliative care.

    Science.gov (United States)

    Destro, Massimo; Ottolini, Luca; Vicentini, Lorenza; Boschetti, Silvia

    2012-10-01

    The parenteral administration of combinations of drugs is often necessary in palliative medicine, particularly in the terminal stage of life, when patients are no longer able to take medication orally. The use of infusers to administer continuous subcutaneous infusions is a well-established practice in the palliative care setting and enables several drugs to be given simultaneously, avoiding the need for repeated administrations and the effects of peaks and troughs in the doses of medication. The method is also appreciated by patients and caregivers in the home care setting because the devices and infusion sites are easy to manage. Despite their frequent use, however, the mixtures of drugs adopted in clinical practice are sometimes not supported by reliable data concerning their chemical and physical compatibility. The present study investigates the chemical compatibility of binary mixtures (morphine with ketorolac) and the physical compatibility of binary (morphine or methadone with ketorolac) or ternary mixtures (morphine with ketorolac and/or haloperidol, and/or dexamethasone, and/or metoclopramide, and/or hyoscine butylbromide) with a view to reducing the aleatory nature of the empirical use of such combinations, thereby increasing their safety and clinical appropriateness. PMID:22252547

  13. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Feng; Lin, Hong; Zhang, Jing [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Li, Jianbao [State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Ministry of Education for Application Technology of Chemical Materials in Hainan Superior Resources, Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti Resources, College of Materials Science and Chemical Engineering, Hainan University, Haikou 570228 (China)

    2011-02-01

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency. (author)

  14. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    Science.gov (United States)

    Hao, Feng; Lin, Hong; Zhang, Jing; Li, Jianbao

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency.

  15. He II $\\lambda$4686 emission from the massive binary system in $\\eta$ Car: constraints to the orbital elements and the nature of the periodic minima

    CERN Document Server

    Teodoro, M; Heathcote, B; Richardson, N D; Moffat, A F J; St-Jean, L; Russell, C; Gull, T R; Madura, T I; Pollard, K R; Walter, F; Coimbra, A; Prates, R; Fernández-Lajús, E; Gamen, R C; Hickel, G; Henrique, W; Navarete, F; Andrade, T; Jablonski, F; Luckas, P; Locke, M; Powles, J; Bohlsen, T; Chini, R; Corcoran, M F; Hamaguchi, K; Groh, J H; Hillier, D J; Weigelt, G

    2016-01-01

    {\\eta} Carinae is an extremely massive binary system in which rapid spectrum variations occur near periastron. Most notably, near periastron the He II $\\lambda 4686$ line increases rapidly in strength, drops to a minimum value, then increases briefly before fading away. To understand this behavior, we conducted an intense spectroscopic monitoring of the He II $\\lambda 4686$ emission line across the 2014.6 periastron passage using ground- and space-based telescopes. Comparison with previous data confirmed the overall repeatability of EW(He II $\\lambda 4686$), the line radial velocities, and the timing of the minimum, though the strongest peak was systematically larger in 2014 than in 2009 by 26%. The EW(He II $\\lambda 4686$) variations, combined with other measurements, yield an orbital period $2022.7\\pm0.3$ d. The observed variability of the EW(He II $\\lambda 4686$) was reproduced by a model in which the line flux primarily arises at the apex of the wind-wind collision and scales inversely with the square of ...

  16. Thermo Physical Properties for Binary Mixture of Dimethylsulfoxide and Isopropylbenzene at Various Temperatures

    Directory of Open Access Journals (Sweden)

    Maninder Kumar

    2013-01-01

    Full Text Available Density, refractive index, speed of sound, and viscosity have been measured of binary mixture dimethylsulfoxide (DMSO + isopropylbenzene (CUMENE over the whole composition range at 298.15, 303.15, 308.15, and 313.15 K and atmospheric pressure. From these experimental measurements the excess molar volume, deviations in viscosity, molar refractivity, speed of sound, and isentropic compressibility have been calculated. These deviations have been correlated by a polynomial Redlich-Kister equation to derive the coefficients and standard error. The viscosities have furthermore been correlated with two or three parameter models, that is, herric correlation and McAllister model, respectively.

  17. Notices to investigation of symbiotic binaries V. Physical parameters derived from UBV magnitudes

    OpenAIRE

    Carikova, Zuzana; Skopal, Augustin

    2010-01-01

    In the optical, the spectrum of symbiotic binaries consists of contributions from the cool giant, symbiotic nebula and the hot star. Strong emission lines are superposed on the continuum. In this paper we introduce a simple method to extract individual components of radiation from photometric UBV magnitudes. We applied the method to classical symbiotic stars AX Per, AG Dra, AG Peg and Z And, the symbiotic novae RR Tel and V1016 Cyg and the classical nova V1974 Cyg during its nebular phase. We...

  18. Illustrating Concepts in Physical Organic Chemistry with 3D Printed Orbitals

    Science.gov (United States)

    Robertson, Michael J.; Jorgensen, William L.

    2015-01-01

    Orbital theory provides a powerful tool for rationalizing and understanding many phenomena in chemistry. In most introductory chemistry courses, students are introduced to atomic and molecular orbitals in the form of two-dimensional drawings. In this work, we describe a general method for producing 3D printing files of orbital models that can be…

  19. Physical and orbital properties of micrometeors observed using the 430 MHz Arecibo observatory radar

    Science.gov (United States)

    Janches, Diego

    Physical and orbital properties of 1200+ radar micrometeors are deduced from more than 8000+ event detections using the 430 MHz Arecibo radar in Puerto Rico. These results are very distinct from classical HF/VHF radar observations in that the head-echo (radar scattering from the region immediately surrounding the meteoroid) is always observed, leading uniquely to very accurate Doppler speed determinations. A multi-pulse technique has been developed that permits the direct measurement of Doppler velocities from the micrometeor leading-edge (or head-echo), and in some 26% of the sample, micrometeor deceleration is also accurately measured. The results from those showing decelerations are described in some detail. The average measured micrometeor velocity is around ˜50 km/sec unlike that obtained with classical low-power VHF radars which is nearly a factor of two lower. The observed micrometeor decelerations range from a few km/sec2 to ˜1000 km/sec2. The measurements of highly resolved meteor altitudes, velocities and decelerations are crucial for understanding a number of aeronomical and astronomical problems in meteor science. One important property, the particle meteor ballistic parameter (BP)---the ratio of the meteoroid mass to cross-sectional area---gives a physical characterization of the decelerating particles independent of any assumption about meteoroid shape and mass density. The BP calculation for these micrometeors results in a distribution that covers a wide range (10-4--10 -1gm/cm2). The sizes and masses that these results represent, when the meteoroid is assumed to be a sphere of density 3 gm/cm3, are radii ˜0.5 x 10-4--2 x 10-2 cm and masses of a fraction of a nanogram to 10 mugm. An original criterion to separate particles that are travelling down-the-beam from those with a more significant across-the-beam velocity component was developed. This criterion is based on the variation of the meteor BP during the time the particles are observed by the

  20. Attempt to explain black hole spin in X-ray binaries with new physics

    CERN Document Server

    Bambi, Cosimo

    2014-01-01

    It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole swallows the whole stellar companion. If the secondary has a high mass, its lifetime is too short to transfer the necessary amount of matter and spin the black hole up. However, while black holes formed from the collapse of a massive star with Solar metallicity are expected to have low birth spin, current spin measurements show that some black holes in X-ray binaries are rotating very rapidly. Here I show that, if these objects are not the Kerr black holes of general relativity, the accretion of a small amount of matter ($\\sim 2$~$M_\\odot$) can make them look like very fast-rotating Kerr black holes. Such a possibility is not in contradiction with any observation and it can explain current spin measurements in a very simple way.

  1. Attempt to explain black hole spin in X-ray binaries by new physics

    International Nuclear Information System (INIS)

    It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole swallows the whole stellar companion. If the secondary has a high mass, its lifetime is too short to transfer the necessary amount of matter and spin the black hole up. However, while black holes formed from the collapse of a massive star with solarmetallicity are expected to have low birth spin, current spin measurements show that some black holes in X-ray binaries are rotating very rapidly. Here we show that, if these objects are not the Kerr black holes of general relativity, the accretion of a small amount of matter (∝2 Msun) can make them look like very fast-rotating Kerr black holes. Such a possibility is not in contradiction with any observation and it can explain current spin measurements in a very simple way. (orig.)

  2. Attempt to explain black hole spin in X-ray binaries by new physics

    Science.gov (United States)

    Bambi, Cosimo

    2015-01-01

    It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole swallows the whole stellar companion. If the secondary has a high mass, its lifetime is too short to transfer the necessary amount of matter and spin the black hole up. However, while black holes formed from the collapse of a massive star with solar metallicity are expected to have low birth spin, current spin measurements show that some black holes in X-ray binaries are rotating very rapidly. Here we show that, if these objects are not the Kerr black holes of general relativity, the accretion of a small amount of matter (2 ) can make them look like very fast-rotating Kerr black holes. Such a possibility is not in contradiction with any observation and it can explain current spin measurements in a very simple way.

  3. He II λ4686 Emission from the Massive Binary System in λ Car: Constraints to the Orbital Elements and the Nature of the Periodic Minima

    Science.gov (United States)

    Teodoro, M.; Damineli, A.; Heathcote, B.; Richardson, N. D.; Moffat, A. F. J.; St-Jean, L.; Russell, C.; Gull, T. R.; Madura, T. I.; Pollard, K. R.; Walter, F.; Coimbra, A.; Prates, R.; Fernández-Lajús, E.; Gamen, R. C.; Hickel, G.; Henrique, W.; Navarete, F.; Andrade, T.; Jablonski, F.; Luckas, P.; Locke, M.; Powles, J.; Bohlsen, T.; Chini, R.; Corcoran, M. F.; Hamaguchi, K.; Groh, J. H.; Hillier, D. J.; Weigelt, G.

    2016-03-01

    Eta Carinae (η Car) is an extremely massive binary system in which rapid spectrum variations occur near periastron. Most notably, near periastron the He ii λ4686 line increases rapidly in strength, drops to a minimum value, then increases briefly before fading away. To understand this behavior, we conducted an intense spectroscopic monitoring of the He ii λ4686 emission line across the 2014.6 periastron passage using ground- and space-based telescopes. Comparison with previous data confirmed the overall repeatability of the line equivalent width (EW), radial velocities, and the timing of the minimum, though the strongest peak was systematically larger in 2014 than in 2009 by 26%. The EW variations, combined with other measurements, yield an orbital period of 2022.7 ± 0.3 days. The observed variability of the EW was reproduced by a model in which the line flux primarily arises at the apex of the wind-wind collision and scales inversely with the square of the stellar separation, if we account for the excess emission as the companion star plunges into the hot inner layers of the primary’s atmosphere, and including absorption from the disturbed primary wind between the source and the observer. This model constrains the orbital inclination to 135°-153°, and the longitude of periastron to 234°-252°. It also suggests that periastron passage occurred on {T}0=2456874.4\\quad (+/- 1.3 days). Our model also reproduced EW variations from a polar view of the primary star as determined from the observed He ii λ 4686 emission scattered off the Homunculus nebula. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program numbers 11506, 12013, 12508, 12750, and 13054. Support for program numbers 12013, 12508, and 12750 was provided by NASA

  4. Low-voltage Power Supply Subsystem for a Sub-Orbital Particle Physic Instrument

    Directory of Open Access Journals (Sweden)

    Hector Hugo Silva Lopez

    2014-01-01

    Full Text Available The Japanese Experiment Module–Extreme Universe Space Observatory (JEM-EUSO is a wide-field (+/-~30°of aperture 2.5m refractor telescope to be installed in the International Space Station (ISS. The instrument looks downward from its orbit, into Earth’s atmosphere, with the main objective of observing ultra-violet (UV fluorescence light generated by Ultra-High Energy Cosmic Rays (UHECR extensive air showers (EAS. It is a frontier particle-physics experiment, the first of its kind. The validation of the technical readiness level of such a complex and unique instrument requires prototypes at several levels of integration. At the highest level, the EUSO-Balloon instrument has been conceived, through French space agency (CNES. At a smaller scale and in suborbital flight, EUSO-Balloon integrates all the sub-systems of the full space JEM-EUSO telescope, allowing end-to-end testing of hardware and interfaces, and to probing the global detection chain and strategy, while improving at the same time our knowledge of atmospheric and terrestrial UV background. EUSO-Balloon will be flown by CNES for the first time from Timmins, Canada; on spring 2014.This article presents the low-voltage power supply (LVPS subsystem development for the EUSO-Balloon instrument. This LVPS is the fully operational prototype for the space instrument JEM-EUSO. Besides design and construction, all performance tests and integration results with the other involved subsystems are shown.

  5. Physics of man-made extended magnetic structures in low earth orbit

    International Nuclear Information System (INIS)

    Recently there have been proposals to place high field magnets aboard the Space Station. The introduction of such an extended magnetic field structure into low earth orbit raises a number of interesting plasma physics issues. For example, the ASTROMAG magnet would create an extended magnet field whose strength drops to the ambient level of .3 G over a scale length of approximately 10 m. The combined field from the cusp magnet and the earth produces a complex extended configuration with ring nulls which separate open from closed field lines. This configuration will move through the ambient 1 x 10/sup 5/ cm/sup -3/ plasma at a velocity of approximately 7 km/sec, a velocity slow compared to the Alfven speed, but fast compared to ion sound speed. The ambient plasma crosses the field structure in a time short compared to an ion Larmor period in the ambient field, but long compared to an electron Larmor period. Thus, electrons behave as a magnetized fluid while ions move ballistically until they approach and reflect from the higher fields near the cusp. Since the ambient plasma Debye length is short compared to the field scale length, an electrostatic shock structure forms to equilibrate the flows in order to achieve quasi-neutrality. The authors conjecture based on previous laboratory experiments that the ambient plasma will be excluded from a cavity surrounding the magnet

  6. Extrasolar Binary Planets II: Detectability by Transit Observations

    CERN Document Server

    Lewis, K M; Nagasawa, M; Ida, S

    2015-01-01

    We discuss the detectability of gravitationally bounded pairs of gas-giant planets (which we call "binary planets") in extrasolar planetary systems that are formed through orbital instability followed by planet-planet dynamical tides during their close encounters, based on the results of N-body simulations by Ochiai, Nagasawa and Ida (Paper I). Paper I showed that the formation probability of a binary is as much as $\\sim 10\\%$ for three giant planet systems that undergo orbital instability, and after post-capture long-term tidal evolution, the typical binary separation is 3--5 times the sum of physical radii of the planets. The binary planets are stable during main sequence lifetime of solar-type stars, if the stellarcentric semimajor axis of the binary is larger than 0.3 AU. We show that detecting modulations of transit light curves is the most promising observational method to detect binary planets. Since the likely binary separations are comparable to the stellar diameter, the shape of the transit light cu...

  7. Kepler Eclipsing Binaries with Stellar Companions

    CERN Document Server

    Gies, D R; Guo, Z; Lester, K V; Orosz, J A; Peters, G J

    2015-01-01

    Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

  8. Physical properties and intermolecular dynamics of an ionic liquid compared with its isoelectronic neutral binary solution.

    Science.gov (United States)

    Shirota, Hideaki; Castner, Edward W

    2005-10-27

    In this study, we address the following question about room-temperature ionic liquids (RTILs). Are the properties of a RTIL more dependent on the charges of the molecular ions or on the fact that the liquid is a complex mixture of two species, one or both of which are asymmetric? To address this question and to better understand the interactions and dynamics in RTILs, we have prepared the organic ionic liquid 1-methoxyethylpyridinium dicyanoamide (MOEPy(+)/DCA(-)) and compared this RTIL with the analogous isoelectronic binary solution, comprised of equal parts of 1-methoxyethylbenzene (MOEBz) and dicyanomethane (DCM). In essence, we have created a RTIL and a nearly identical neutral pair in which we have effectively turned off the charges. To understand the intermolecular interactions in both of these liquids, we have characterized the bulk density and shear viscosity. Using femtosecond optical Kerr effect spectroscopy, we have also characterized the intermolecular vibrational dynamics and diffusive reorientation. To verify that the shape, polarizability, and electronic structure of the RTIL ions and the components of the neutral pair are truly quite similar, we have carried out density functional theory calculations on the individual molecular ion and neutral species. PMID:16866386

  9. HIDES spectroscopy of bright detached eclipsing binaries from the $Kepler$ field - I. Single-lined objects

    CERN Document Server

    Hełminiak, K G; Kambe, E; Kozłowski, S K; Sybilski, P; Ratajczak, M; Maehara, H; Konacki, M

    2016-01-01

    We present results of our spectroscopic observations of nine detached eclipsing binaries (DEBs), selected from the $Kepler$ Eclipsing Binary Catalog, that only show one set of spectral lines. Radial velocities (RVs) were calculated from the high resolution spectra obtained with the HIDES instrument, attached to the 1.88-m telescope at the Okayama Astrophysical Observatory, and from the public APOGEE archive. In our sample we found five single-lined binaries, with one component dominating the spectrum. The orbital and light curve solutions were found for four of them, and compared with isochrones, in order to estimate absolute physical parameters and evolutionary status of the components. For the fifth case we only update the orbital parameters, and estimate the properties of the unseen star. Two other systems show orbital motion with a period known from the eclipse timing variations (ETVs). For these we obtained parameters of outer orbits, by translating the ETVs to RVs of the centre of mass of the eclipsing ...

  10. Orbits of Six Binary Stars

    Directory of Open Access Journals (Sweden)

    D. Olevic

    2005-01-01

    Full Text Available Se presentan los elementos orbitales de sistemas binarios WDS 03494{1956 = RST 2324, WDS 03513+2621 = A 1830, WDS 04093{2025 = RST 2333, WDS 06485{1226 = A 2935, WDS 07013{0906 = A 671 y WDS 18323{1439 = CHR 73. Se derivan las masas individuales y las paralajes dinámicas para todos los sistemas con excepción de WDS 18323-1439.

  11. Future gravitational physics tests from ranging to the BepiColombo Mercury planetary orbiter

    International Nuclear Information System (INIS)

    Milani et al. recently have published careful and fundamental studies of the accuracy with which both gravitational physics information and the solar quadrupole moment can be obtained from Earth-Mercury distance data. To complement these results, a quite different analysis method is used in the present paper. We calculate the first-order corrections to the Keplerian motion of a single planet around the Sun due to the parameterized post-Newtonian theory parameters β, γ, α1, α2, and ξ, as well as corrections due to the solar quadrupole moment J2 and a possible secular change in GM·. The Nordtvedt parameter η that is used in tests of the strong equivalence principle also is included in this analysis. The expected accuracies are given for 1 yr, 2 yr, and 8 yr mission durations, assuming that the planet-planet and asteroid-planet perturbations are accurately known. The ''modified worst-case'' error analysis method that we use is quite different from the usual covariance analysis method based on assumed uncorrelated random errors, plus a bias that is fixed or that changes in a prescribed way. We believe this is appropriate because systematic measurement errors are likely to be the main limitation on the accuracy of the results. Our final estimated uncertainties are one-third of the errors that would result if a 4.5-cm rms systematic error had the most damaging possible variation with time. We discuss the resulting uncertainties for several different subsets of orbital and relativity parameters

  12. Two-body physics in quasi-low-dimensional atomic gases under spin-orbit coupling

    Science.gov (United States)

    Wang, Jing-Kun; Yi, Wei; Zhang, Wei

    2016-06-01

    One of the most dynamic directions in ultracold atomic gas research is the study of low-dimensional physics in quasi-low-dimensional geometries, where atoms are confined in strongly anisotropic traps. Recently, interest has significantly intensified with the realization of synthetic spin-orbit coupling (SOC). As a first step toward understanding the SOC effect in quasi-low-dimensional systems, the solution of two-body problems in different trapping geometries and different types of SOC has attracted great attention in the past few years. In this review, we discuss both the scattering-state and the bound-state solutions of two-body problems in quasi-one and quasi-two dimensions. We show that the degrees of freedom in tightly confined dimensions, in particular with the presence of SOC, may significantly affect system properties. Specifically, in a quasi-one-dimensional atomic gas, a one-dimensional SOC can shift the positions of confinement-induced resonances whereas, in quasitwo- dimensional gases, a Rashba-type SOC tends to increase the two-body binding energy, such that more excited states in the tightly confined direction are occupied and the system is driven further away from a purely two-dimensional gas. The effects of the excited states can be incorporated by adopting an effective low-dimensional Hamiltonian having the form of a two-channel model. With the bare parameters fixed by two-body solutions, this effective Hamiltonian leads to qualitatively different many-body properties compared to a purely low-dimensional model.

  13. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    XU PeiLiang

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth's gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  14. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth’s gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  15. An Eccentric Binary Millisecond Pulsar in the Galactic Plane

    Science.gov (United States)

    Champion, David J.; Ransom, Scott M.; Lazarus, Patrick; Camilo, Fernando; Bassa, Cess; Kaspi, Victoria M.; Nice, David J.; Freire, Paulo C. C.; Stairs, Ingrid H.; vanLeeuwen, Joeri; Stappers, Ben W.; Cordes, James M.; Hessels, Jason W. T.; Lorimer, Duncan R.; Arzoumanian, Zaven; Backer, Don C.; Bhat, N. D. Ramesh; Chatterjee, Shami; Cognard, Ismael; Deneva, Julia S.; Faucher-Giguere, Claude-Andre; Gaensler, Bryan M.; Han, JinLin; Jenet, Fredrick A.; Kasian, Laura

    2008-01-01

    Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M.) companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster, then ejecting it into the Galactic disk, or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74 +/- 0.04 Solar Mass, an unusually high value.

  16. Astrophysics, cosmology, and fundamental physics with compact binary coalescence and the Einstein Telescope

    CERN Document Server

    Broeck, Chris Van Den

    2013-01-01

    The second-generation interferometric gravitational wave detectors currently under construction are expected to make their first detections within this decade. This will firmly establish gravitational wave physics as an empirical science and will open up a new era in astrophysics, cosmology, and fundamental physics. Already with the first detections, we will be able to, among other things, establish the nature of short-hard gamma ray bursts, definitively confirm the existence of black holes, measure the Hubble constant in a completely independent way, and for the first time gain access to the genuinely strong-field dynamics of gravity. Hence it is timely to consider the longer-term future of this new field. The Einstein Telescope (ET) is a concrete conceptual proposal for a third-generation gravitational wave observatory, which will be ~10 times more sensitive in strain than the second-generation detectors. This will give access to sources at cosmological distances, with a correspondingly higher detection rat...

  17. The birth of mathematical physics : Kepler's proof of the planets' elliptical orbits from causal hypotheses

    OpenAIRE

    Tønnessen, Sigurd

    2012-01-01

    Johannes Kepler (1571-1630) was an iconographic scientist and one of the forefathers of the scientific revolution. His groundbreaking work on astronomy has been extensively used in the study of scientific progress. I have continued this tradition in this thesis, and have studied Kepler’s original work in order to understand his theory development. More specifically, I have studied Kepler’s analysis on planetary orbits, how he deduced the correct planetary orbits from his analyses, and what ex...

  18. LUT observations of the mass-transferring binary AI Dra

    Science.gov (United States)

    Liao, Wenping; Qian, Shengbang; Li, Linjia; Zhou, Xiao; Zhao, Ergang; Liu, Nianping

    2016-06-01

    Complete UV band light curve of the eclipsing binary AI Dra was observed with the Lunar-based Ultraviolet Telescope (LUT) in October 2014. It is very useful to adopt this continuous and uninterrupted light curve to determine physical and orbital parameters of the binary system. Photometric solutions of the spot model are obtained by using the W-D (Wilson and Devinney) method. It is confirmed that AI Dra is a semi-detached binary with secondary component filling its critical Roche lobe, which indicates that a mass transfer from the secondary component to the primary one should happen. Orbital period analysis based on all available eclipse times suggests a secular period increase and two cyclic variations. The secular period increase was interpreted by mass transfer from the secondary component to the primary one at a rate of 4.12 ×10^{-8}M_{⊙}/yr, which is in agreement with the photometric solutions. Two cyclic oscillations were due to light travel-time effect (LTTE) via the presence of two cool stellar companions in a near 2:1 mean-motion resonance. Both photometric solutions and orbital period analysis confirm that AI Dra is a mass-transferring binary, the massive primary is filling 69 % of its critical Roche lobe. After the primary evolves to fill the critical Roche lobe, the mass transfer will be reversed and the binary will evolve into a contact configuration.

  19. Perturbative construction of the periodic orbits of the mean-field equations in nuclear physics

    International Nuclear Information System (INIS)

    We have presented a perturbative construction method of the periodic orbits of the time-dependent Hartree-Fock equations (TDHF). The solutions are found in the form of a power series in the amplitude of the collective motion. We have performed calculations using third order expansions to determine the splitting of two-phonon states of the low-lying octupole vibration in oxygen-16 and calcium-40. We have also investigated giant quadrupole vibrations. We had to generalize our method in order to account for the resonant coupling between the two-phonon state and one-phonon states in the continuum. This was done by introducing admixture of the resonant mode in the first order expression of the periodic orbit. Our results demonstrate that the method of quantization of periodic orbits of TDHF equation is a powerful tool to investigate the energy spectra of many-body systems. We have used our method to build the classical periodic orbits of a Skyrmion. The method, used up to second order, has been applied to the Roper resonance described in terms of monopole vibrations. To first order the method is equivalent to linear response theory and we find that the response function displays a well developed peak. We have also presented a powerful method which uses the knowledge of periodic orbits to construct a collective Bohr-type Hamiltonian. We have applied it to the case of monopole vibrations of the Skyrmion and derived the corresponding first anharmonic terms in the collective Hamiltonian

  20. Physical properties of asteroids in comet-like orbits in infrared asteroid survey catalogs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoonyoung; Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, Gwanak, Seoul 151-742 (Korea, Republic of); Usui, Fumihiko [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2014-07-10

    We investigated the population of asteroids in comet-like orbits using available asteroid size and albedo catalogs of data taken with the Infrared Astronomical Satellite, AKARI, and the Wide-field Infrared Survey Explorer on the basis of their orbital properties (i.e., the Tisserand parameter with respect to Jupiter, T{sub J}, and the aphelion distance, Q). We found that (1) there are 123 asteroids in comet-like orbits by our criteria (i.e., Q > 4.5 AU and T{sub J} < 3), (2) 80% of them have low albedo, p{sub v} < 0.1, consistent with comet nuclei, (3) the low-albedo objects among them have a size distribution shallower than that of active comet nuclei, that is, the power index of the cumulative size distribution is around 1.1, and (4) unexpectedly, a considerable number (i.e., 25 by our criteria) of asteroids in comet-like orbits have high albedo, p{sub v} > 0.1. We noticed that such high-albedo objects mostly consist of small (D < 3 km) bodies distributed in near-Earth space (with perihelion distance of q < 1.3 AU). We suggest that such high-albedo, small objects were susceptible to the Yarkovsky effect and drifted into comet-like orbits via chaotic resonances with planets.

  1. PHYSICAL CHARACTERISTICS AND NON-KEPLERIAN ORBITAL MOTION OF 'PROPELLER' MOONS EMBEDDED IN SATURN'S RINGS

    International Nuclear Information System (INIS)

    We report the discovery of several large 'propeller' moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5 year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1-2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-Keplerian orbit motion.

  2. Physics of the Mind:. Opinion Dynamics and Decision Making Processes Based on a Binary Network Model

    Science.gov (United States)

    Kusmartsev, F. V.; Kürten, Karl E.

    2009-12-01

    We propose a new theory of the human mind. The formation of human mind is considered as a collective process of the mutual interaction of people via exchange of opinions and formation of collective decisions. We investigate the associated dynamical processes of the decision making when people are put in different conditions including risk situations in natural catastrophes when the decision must be made very fast or at national elections. We also investigate conditions at which the fast formation of opinion is arising as a result of open discussions or public vote. Under a risk condition the system is very close to chaos and therefore the opinion formation is related to the order disorder transition. We study dramatic changes which may happen with societies which in physical terms may be considered as phase transitions from ordered to chaotic behavior. Our results are applicable to changes which are arising in various social networks as well as in opinion formation arising as a result of open discussions. One focus of this study is the determination of critical parameters, which influence a formation of stable mind, public opinion and where the society is placed "at the edge of chaos". We show that social networks have both, the necessary stability and the potential for evolutionary improvements or self-destruction. We also show that the time needed for a discussion to take a proper decision depends crucially on the nature of the interactions between the entities as well as on the topology of the social networks.

  3. Physical characteristics and non-keplerian orbital motion of "propeller" moons embedded in Saturn's rings

    CERN Document Server

    Tiscareno, Matthew S; Sremčević, Miodrag; Beurle, Kevin; Hedman, Matthew M; Cooper, Nicholas J; Milano, Anthony J; Evans, Michael W; Porco, Carolyn C; Spitale, Joseph N; Weiss, John W

    2010-01-01

    We report the discovery of several large "propeller" moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5-year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1--2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-keplerian orbit motion. (Note: This arXiv version of the paper contains supplementary tables that were left out of the ApJL version due to lack of space).

  4. Statistics of Mars' topography from the Mars Orbiter Laser Altimeter: Slopes, correlations, and physical Models

    OpenAIRE

    Aharonson, Oded; Zuber, Maria T.; Rothman, Daniel H.

    2001-01-01

    Data obtained recently by the Mars Orbiter Laser Altimeter (MOLA) were used to study the statistical properties of the topography and slopes on Mars. We find that the hemispheric dichotomy, manifested as an elevation difference, can be described by long baseline tilts but in places is expressed as steeper slopes. The bimodal hypsometry of elevations on Mars becomes unimodal when referenced to the center of figure, contrary to the Earth, for which the bimodality is retained. However, ruling ou...

  5. An M-dwarf star in the transition disk of Herbig HD142527; Physical parameters and orbital elements

    CERN Document Server

    Lacour, S; Cheetham, A; Greenbaum, A; Pearce, T; Marino, S; Tuthill, P; Pueyo, L; Mamajek, E E; Girard, J H; Sivaramakrishnan, A; Bonnefoy, M; Baraffe, I; Chauvin, G; Olofsson, J; Juhasz, A; Benisty, M; Pott, J -U; Sicilia-Aguilar, A; Henning, T; Cardwell, A; Goodsell, S; Graham, J R; Hibon, P; Ingraham, P; Konopacky, Q; Macintosh, B; Oppenheimer, R; Perrin, M; Rantakyrö, F; Sadakuni, N; Thomas, S

    2015-01-01

    HD 142527A is one of the most studied Herbig Ae/Be stars with a transitional disk, as it has the largest imaged gap in any protoplanetary disk: the gas is cleared from 30 to 90 AU. The HD 142527 system is also unique in that it has a stellar companion with a small mass compared to the mass of the primary star. This factor of $\\approx20$ in mass ratio between the two objects makes this binary system different from any other YSO. The HD142527 system could therefore provides a valuable testbed for understanding the impact of a lower mass companion on disk structure. This low-mass stellar object may be responsible for both the gap and the dust trapping observed by ALMA at longer distances. We have observed this system with the NACO and GPI instruments using the aperture masking technique. Aperture masking is ideal for providing high dynamic range even at very small angular separations. We present here the SEDS for HD 142527A and B from the $R$ band up to the $M$ band as well as the orbital motion of HD 142527B ov...

  6. Fingerprints of entangled spin and orbital physics in itinerant ferromagnets via angle-resolved resonant photoemission

    Science.gov (United States)

    Da Pieve, F.

    2016-01-01

    A method for mapping the local spin and orbital nature of the ground state of a system via corresponding flip excitations is proposed based on angle-resolved resonant photoemission and related diffraction patterns, obtained here via an ab initio modified one-step theory of photoemission. The analysis is done on the paradigmatic weak itinerant ferromagnet bcc Fe, whose magnetism, a correlation phenomenon given by the coexistence of localized moments and itinerant electrons, and the observed non-Fermi-Liquid behavior at extreme conditions both remain unclear. The combined analysis of energy spectra and diffraction patterns offers a mapping of local pure spin-flip, entangled spin-flip-orbital-flip excitations and chiral transitions with vortexlike wave fronts of photoelectrons, depending on the valence orbital symmetry and the direction of the local magnetic moment. Such effects, mediated by the hole polarization, make resonant photoemission a promising tool to perform a full tomography of the local magnetic properties even in itinerant ferromagnets or macroscopically nonmagnetic systems.

  7. Extrasolar binary planets. I. Formation by tidal capture during planet-planet scattering

    Energy Technology Data Exchange (ETDEWEB)

    Ochiai, H. [Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Nagasawa, M. [Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Ida, S., E-mail: nagasawa.m.ad@m.titech.ac.jp [Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2014-08-01

    We have investigated (1) the formation of gravitationally bounded pairs of gas-giant planets (which we call 'binary planets') from capturing each other through planet-planet dynamical tide during their close encounters and (2) the subsequent long-term orbital evolution due to planet-planet and planet-star quasi-static tides. For the initial evolution in phase 1, we carried out N-body simulations of the systems consisting of three Jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing, and this fraction is almost independent of the initial stellarcentric semimajor axes of the planets, while ejection and merging rates sensitively depend on the semimajor axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by long-term quasi-static tide. We analytically calculated the quasi-static tidal evolution in phase 2. The binary planets first enter the spin-orbit synchronous state by the planet-planet tide. The planet-star tide removes angular momentum of the binary motion, eventually resulting in a collision between the planets. However, we found that the binary planets survive the tidal decay for the main-sequence lifetime of solar-type stars (∼10 Gyr), if the binary planets are beyond ∼0.3 AU from the central stars. These results suggest that the binary planets can be detected by transit observations at ≳ 0.3 AU.

  8. Extrasolar binary planets. I. Formation by tidal capture during planet-planet scattering

    International Nuclear Information System (INIS)

    We have investigated (1) the formation of gravitationally bounded pairs of gas-giant planets (which we call 'binary planets') from capturing each other through planet-planet dynamical tide during their close encounters and (2) the subsequent long-term orbital evolution due to planet-planet and planet-star quasi-static tides. For the initial evolution in phase 1, we carried out N-body simulations of the systems consisting of three Jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing, and this fraction is almost independent of the initial stellarcentric semimajor axes of the planets, while ejection and merging rates sensitively depend on the semimajor axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by long-term quasi-static tide. We analytically calculated the quasi-static tidal evolution in phase 2. The binary planets first enter the spin-orbit synchronous state by the planet-planet tide. The planet-star tide removes angular momentum of the binary motion, eventually resulting in a collision between the planets. However, we found that the binary planets survive the tidal decay for the main-sequence lifetime of solar-type stars (∼10 Gyr), if the binary planets are beyond ∼0.3 AU from the central stars. These results suggest that the binary planets can be detected by transit observations at ≳ 0.3 AU.

  9. Material content of binary physical mixtures as measured with a dual-energy beam of γ rays

    International Nuclear Information System (INIS)

    The content of water and soil in physical intermixtures was measured simultaneously and nondestructively by the attenuation of a dual-energy beam of γ rays. The beam, 1 mm by about 3 cm in cross section, was devised by placing a 280-mCi source of 137Cs behind a 389-mCi source of 241Am, with lead collimators suitably aligned in front of each source and the scintillation probe. The probe was connected in parallel to two separate amplifier-analyzer-scaler systems, one being set in the integral mode to receive all pulses greater than 550 keV (for 137Cs, 662-keV peak), with the other being set in the differential mode to receive all pulses in a band 35 to 85 keV (for 241Am, 60-keV peak). When related to the count intensity in the high-energy range, the count intensity e caused by 137Cs in the low-energy band was empirically found to be independent of the material in the binary mixture (soil and/or water) placed in the beam for measurement. Also, e could be well expressed by a cubic polynomial that was then used along with a dead-time correction to determine the attenuated count intensity attributable to the 241Am source alone. Calibration of the system was then possible. Over-all measuring accuracy was on the order of plus-minus 0.01 cm3/cm3 in water content and plus-minus 0.02 g/cm3 in soil content (bulk density) for a counting period of 5 min; these changed to plus-minus 0.04 cm3/cm3 or g/cm3 for a counting period of 5 sec. (U.S.)

  10. An M-dwarf star in the transition disk of Herbig HD 142527. Physical parameters and orbital elements

    Science.gov (United States)

    Lacour, S.; Biller, B.; Cheetham, A.; Greenbaum, A.; Pearce, T.; Marino, S.; Tuthill, P.; Pueyo, L.; Mamajek, E. E.; Girard, J. H.; Sivaramakrishnan, A.; Bonnefoy, M.; Baraffe, I.; Chauvin, G.; Olofsson, J.; Juhasz, A.; Benisty, M.; Pott, J.-U.; Sicilia-Aguilar, A.; Henning, T.; Cardwell, A.; Goodsell, S.; Graham, J. R.; Hibon, P.; Ingraham, P.; Konopacky, Q.; Macintosh, B.; Oppenheimer, R.; Perrin, M.; Rantakyrö, F.; Sadakuni, N.; Thomas, S.

    2016-05-01

    Aims: HD 42527A is one of the most studied Herbig Ae/Be stars with a transitional disk, as it has the largest imaged gap in any protoplanetary disk: the gas is cleared from 30 to 90 AU. The HD 142527 system is also unique in that it has a stellar companion with a small mass compared to the mass of the primary star. This factor of ≈20 in mass ratio between the two objects makes this binary system different from any other YSO. The HD 142527 system could therefore provide a valuable test bed for understanding the impact of a lower mass companion on disk structure. This low-mass stellar object may be responsible for both the gap and dust trapping observed by ALMA at longer distances. Methods: We observed this system with the NACO and GPI instruments using the aperture masking technique. Aperture masking is ideal for providing high dynamic range even at very small angular separations. We present the spectral energy distribution (SED) for HD 142527A and B. Brightness of the companion is now known from the R band up to the M' band. We also followed the orbital motion of HD 142527B over a period of more than two years. Results: The SED of the companion is compatible with a T = 3000 ± 100 K object in addition to a 1700 K blackbody environment (likely a circum-secondary disk). From evolution models, we find that it is compatible with an object of mass 0.13 ± 0.03 M⊙, radius 0.90 ± 0.15 R⊙, and age Myr. This age is significantly younger than the age previously estimated for HD 142527A. Computations to constrain the orbital parameters found a semimajor axis of mas, an eccentricity of 0.5 ± 0.2, an inclination of 125 ± 15 degrees, and a position angle of the right ascending node of -5 ± 40 degrees. Inclination and position angle of the ascending node are in agreement with an orbit coplanar with the inner disk, not coplanar with the outer disk. Despite its high eccentricity, it is unlikely that HD 142527B is responsible for truncating the inner edge of the outer disk.

  11. Spin and orbital angular momentum exchange in binary star systems II. Ascending the giant branch: a new path to FK Comae stars

    NARCIS (Netherlands)

    Keppens, R.; Solanki, S. K.; Charbonnel, C.

    2000-01-01

    Using the model by Keppens (1997), we investigate the angular momentum (AM) evolution in asymmetric binary star systems from Zero-Age Main Sequence times until at least one component has ascended the giant branch. We concentrate on stars ranging in mass from 0.9 M. - 1.7 M. in almost synchronous, sh

  12. Effect of the temperature on the physical properties of pure 1-propyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide and characterization of its binary mixtures with alcohols

    International Nuclear Information System (INIS)

    Highlights: ► The temperature dependence of the physical properties of [PMim][NTf2] was studied. ► Physical properties of its binary mixtures with alcohols were determined at 298.15 K. ► The thermal expansion coefficient of the pure ionic liquid was calculated. ► The heat capacity of the pure ionic liquid at 298.15 K was determined. ► The excess properties of binary mixtures were adjusted with Redlich–Kister equation. - Abstract: In this paper, physical properties of a high purity sample of the ionic liquid 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf2], and its binary mixtures with methanol, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure. The temperature dependence of density, refractive index and speed of sound (293.15 to 343.15) K and dynamic viscosity (298.15 to 343.15) K were studied at atmospheric pressure by conventional techniques for the pure ionic liquid. For its mixtures with alcohols, density, speed of sound, and refractive index were measured at T = 298.15 K over the whole composition range. The thermal expansion coefficient of the [PMim][NTf2] was calculated from the experimental results using an empirical equation, and values of the excess molar volume, excess refractive index, and excess molar isentropic compressibility for the binary systems at the above mentioned temperature, were calculated and fitted to the Redlich–Kister equation. The heat capacity of the pure ionic liquid at T = 298.15 K was determined using DSC.

  13. The Formation and Evolution of Wind-Capture Disks In Binary Systems

    CERN Document Server

    Huarte-Espinosa, Martin; Nordhaus, Jason; Frank, Adam; Blackman, Eric G

    2012-01-01

    We study the formation, evolution and physical properties of accretion disks formed via wind capture in binary systems. Using the AMR code AstroBEAR, we have carried out high resolution 3D simulations that follow a stellar mass secondary in the co-rotating frame as it orbits a wind producing AGB primary. We first derive a resolution criteria, based on considerations of Bondi-Hoyle flows, that must be met in order to properly resolve the formation of accretion disks around the secondary. We then compare simulations of binaries with three different orbital radii (10, 15, 20 AU). Disks are formed in all three cases, however the size of the disk and, most importantly, its accretion rate decreases with orbital radii. In addition, the shape of the orbital motions of material within the disk becomes increasingly elliptical with increasing binary separation. The flow is mildly unsteady with "fluttering" around the bow shock observed. The disks are generally well aligned with the orbital plane after a few binary orbit...

  14. Effect of the temperature on the physical properties of the pure ionic liquid 1-ethyl-3-methylimidazolium methylsulfate and characterization of its binary mixtures with alcohols

    International Nuclear Information System (INIS)

    Highlights: • Physical properties of the pure [EMim][MSO4] ionic liquid. • Physical and excess properties of its binary mixtures with alcohols. • The excess properties were fitted using the Redlich–Kister equation. • The effect of temperature on the VE, and KS,mE was analyzed. - Abstract: Experimental density, speed of sound, refractive index and viscosity data of the pure ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO4], were measured as a function of temperature from T = (293.15 to 343.15) K, every 5 K, and atmospheric pressure. Density, speed of sound and refractive index data were satisfactorily correlated with a linear equation, while viscosity data were fitted to the Vogel–Fulcher–Tamman (VFT) equation. Besides, from the experimental density values, the thermal expansion coefficient, α, was calculated. Furthermore, density and speed of sound for the binary systems of {methanol, or ethanol, or 1-propanol, or 2-propanol, or 1-butanol, or 1-pentanol + [EMim][MSO4]} were experimentally determined over the whole composition range, at T = (288.15, 298.15 and 308.15) K and p = 0.1 MPa. These properties were used to calculate the corresponding excess molar volumes and excess molar isentropic compressions, which were satisfactorily fitted to the Redlich–Kister equation. Finally, a comparison with available literature data was also carried out and the obtained results are discussed in terms of interactions and structure factors in these binary mixtures

  15. Discs in misaligned binary systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2016-01-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...

  16. Planetary Dynamics and Habitable Planet Formation In Binary Star Systems

    CERN Document Server

    Haghighipour, Nader; Pilat-Lohinger, Elke

    2009-01-01

    Whether binaries can harbor potentially habitable planets depends on several factors including the physical properties and the orbital characteristics of the binary system. While the former determines the location of the habitable zone (HZ), the latter affects the dynamics of the material from which terrestrial planets are formed (i.e., planetesimals and planetary embryos), and drives the final architecture of the planets assembly. In order for a habitable planet to form in a binary star system, these two factors have to work in harmony. That is, the orbital dynamics of the two stars and their interactions with the planet-forming material have to allow terrestrial planet formation in the habitable zone, and ensure that the orbit of a potentially habitable planet will be stable for long times. We have organized this chapter with the same order in mind. We begin by presenting a general discussion on the motion of planets in binary stars and their stability. We then discuss the stability of terrestrial planets, ...

  17. Binaries in the Hipparcos data: Keep digging

    CERN Document Server

    Pourbaix, D; Jorissen, A

    2004-01-01

    Among the 120 000 objects in the Hipparcos catalogue, only 235 were fitted with an orbital model. Besides these 235 original astrometric binaries, most Hipparcos entries with a known spectroscopic orbit (extrasolar planet or stellar companion) have now been re-processed, as part of the on-going construction of the 9th Catalogue of Spectroscopic Binary Orbits (SB9, available at http://sb9.astro.ulb.ac.be). The pitfalls and successes of this re-processing are discussed in various contexts, like (i) orbital inclinations: the holy grail for extrasolar planets (ii) searching for binaries without a priori knowledge of their spectroscopic orbital elements, and application to barium stars (iii) why not all SB9 entries yield acceptable astrometric solutions? The lessons learned from this study are useful to devise the best possible binary-detection and orbit-determination algorithms for future astrometric missions like GAIA.

  18. High-Energy Physics with Particles Carrying Non-Zero Orbital Angular Momentum

    International Nuclear Information System (INIS)

    Thanks to progress in optics in the past two decades, it is possible to create photons carrying well-defined non-zero orbital angular momentum (OAM). Boosting these photons into high-energy range preserving their OAM seems feasible. Intermediate energy electrons with OAM have also been produced recently. One can, therefore, view OAM as a new degree of freedom in high-energy collisions and ask what novel insights it can bring. Here we discuss generic features of scattering processes involving twisted particles in the initial state. We show that they make it possible to perform a Fourier analysis of a plane wave cross section with respect to the azimuthal angles of the initial particles, and to probe the autocorrelation function of the amplitude, a quantity inaccessible in plane wave collisions. (author)

  19. Interim results from the ongoing hunt for supermassive black hole binaries

    Science.gov (United States)

    Runnoe, Jessie C.; Mathes, Gavin; Pennell, Alison; Brown, Stephanie Meghan; Eracleous, Michael; Boroson, Todd A.; Bogdanovic, Tamara; Sigurdsson, Steinn; Halpern, Jules P.; Liu, Jia

    2016-01-01

    Supermassive black hole binaries seem to be an inevitable product of the prevailing galaxy evolution scenarios in which most massive galaxies play host to a central black hole and undergo a history of mergers and accretion over the course of cosmic time. The early stages of this process have been observed in the form of interacting galaxy pairs as well dual active galactic nuclei with kilo-parsec separations, but detections of the close, bound binaries that are expected to follow have proven elusive. With this motivation, we have been conducting a systematic observational search for sub-parsec separation supermassive black hole binaries. Specifically, we test the hypothesis that the secondary black hole in the system is active and the resulting broad emission lines are doppler shifted due to orbital motion in the binary (analogous to a single-line spectroscopc binary star). Our sample includes 88 binary candidates selected from z1000 km/s) of their broad Hβ emission lines relative to their systemic redshifts. I will present the latest results from the spectroscopic monitoring campaign that we are conducting to constrain the nature of the binary candidates. These include the radial velocity curves, which now use observations made through 2015, and the constraints that can be placed on the physical properties of the binary based on the radial velocity curves and observed flux variability of the binaries.

  20. Detection of an orbital period in the supergiant high mass X-ray binary IGR J16465$-$4507 with Swift-BAT

    CERN Document Server

    La Parola, V; Romano, P; Segreto, A; Vercellone, S; Chincarini, G; 10.1111/j.1745-3933.2010.00860.x

    2010-01-01

    We analysed the IGR J16465-4507 Burst Alert Teelescope survey data collected during the first 54 months of the Swift mission. The source is in a crowded field and it is revealed through an ad hoc imaging analysis at a significance level of ~14 standard deviations. The 15-50 keV average flux is ~3E-11 erg/cm^2/s. The timing analysis reveals an orbital period of 30.243 +/- 0.035 days. The folded light curve shows the presence of a wide phase interval of minimum intensity, lasting ~20% of the orbital period. This could be explained with a full eclipse of the compact object in an extremely eccentric orbit or with the passage of the compact source through a lower density wind at the orbit apastron. The modest dynamical range observed during the BAT monitoring suggests that IGR J16465-4507 is a wind-fed system, continuously accreting from a rather homogeneous wind, and not a member of the Supergiant Fast X-ray Transient class.

  1. The Aid of Optical Studies in Understanding Millisecond Pulsar Binaries

    CERN Document Server

    Wadiasingh, Zorawar; Venter, Christo; Boettcher, Markus

    2016-01-01

    A large number of new "black widow" and "redback" energetic millisecond pulsars with irradiated stellar companions have been discovered through radio and optical searches of unidentified \\textit{Fermi} sources. Synchrotron emission, from particles accelerated up to several TeV in the intrabinary shock, exhibits modulation at the binary orbital period. Our simulated double-peaked X-ray light curves modulated at the orbital period, produced by relativistic Doppler-boosting along the intrabinary shock, are found to qualitatively match those observed in many sources. In this model, redbacks and transitional pulsar systems where the double-peaked X-ray light curve is observed at inferior conjunction have intrinsically different shock geometry than other millisecond pulsar binaries where the light curve is centered at superior conjunction. We discuss, and advocate, how current and future optical observations may aid in constraining the emission geometry, intrabinary shock and the unknown physics of pulsar winds.

  2. Gravitational waves from individual supermassive black hole binaries in circular orbits: limits from the North American nanohertz observatory for gravitational waves

    International Nuclear Information System (INIS)

    We perform a search for continuous gravitational waves from individual supermassive black hole binaries using robust frequentist and Bayesian techniques. We augment standard pulsar timing models with the addition of time-variable dispersion measure and frequency variable pulse shape terms. We apply our techniques to the Five Year Data Release from the North American Nanohertz Observatory for Gravitational Waves. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 pulsar data set we place a 95% upper limit on the strain amplitude of h 0 ≲ 3.0 × 10–14 at a frequency of 10 nHz. Furthermore, we place 95% sky-averaged lower limits on the luminosity distance to such gravitational wave sources, finding that dL ≳ 425 Mpc for sources at a frequency of 10 nHz and chirp mass 1010 M ☉. We find that for gravitational wave sources near our best timed pulsars in the sky, the sensitivity of the pulsar timing array is increased by a factor of ∼four over the sky-averaged sensitivity. Finally we place limits on the coalescence rate of the most massive supermassive black hole binaries.

  3. Gravitational waves from individual supermassive black hole binaries in circular orbits: limits from the North American nanohertz observatory for gravitational waves

    Energy Technology Data Exchange (ETDEWEB)

    Arzoumanian, Z. [Center for Research and Exploration in Space Science and Technology and X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Brazier, A.; Chatterjee, S.; Cordes, J. M.; Dolch, T.; Lam, M. T. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Burke-Spolaor, S. [California Institute of Technology, Pasadena, CA 91125 (United States); Chamberlin, S. J.; Ellis, J. A. [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States); Demorest, P. B. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Deng, X.; Koop, M. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Ferdman, R. D.; Kaspi, V. M. [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Garver-Daniels, N.; Lorimer, D. R. [Department of Physics, West Virginia University, P.O. Box 6315, Morgantown, WV 26505 (United States); Jenet, F. [Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Jones, G. [Department of Physics, Columbia University, New York, NY 10027 (United States); Lazio, T. J. W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91106 (United States); Lommen, A. N., E-mail: justin.ellis18@gmail.com [Department of Physics and Astronomy, Franklin and Marshall College, P.O. Box 3003, Lancaster, PA 17604 (United States); Collaboration: NANOGrav Collaboration; and others

    2014-10-20

    We perform a search for continuous gravitational waves from individual supermassive black hole binaries using robust frequentist and Bayesian techniques. We augment standard pulsar timing models with the addition of time-variable dispersion measure and frequency variable pulse shape terms. We apply our techniques to the Five Year Data Release from the North American Nanohertz Observatory for Gravitational Waves. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 pulsar data set we place a 95% upper limit on the strain amplitude of h {sub 0} ≲ 3.0 × 10{sup –14} at a frequency of 10 nHz. Furthermore, we place 95% sky-averaged lower limits on the luminosity distance to such gravitational wave sources, finding that d{sub L} ≳ 425 Mpc for sources at a frequency of 10 nHz and chirp mass 10{sup 10} M {sub ☉}. We find that for gravitational wave sources near our best timed pulsars in the sky, the sensitivity of the pulsar timing array is increased by a factor of ∼four over the sky-averaged sensitivity. Finally we place limits on the coalescence rate of the most massive supermassive black hole binaries.

  4. Natural bond orbital analysis of molecular interactions: Theoretical studies of binary complexes of HF, H2O, NH3, N2, O2, F2, CO, and CO2 with HF, H2O, and NH3

    International Nuclear Information System (INIS)

    The binary complexes of HF, H2O, NH3, N2, O2, F2, CO, and CO2 with HF, H2O, and NH3 have been studied by ab initio molecular orbital theory and natural bond orbital (NBO) analysis. Most of the complexes involving N2, O2, F2, CO, and CO2 are found to have both hydrogen-bonded and non-hydrogen-bonded structures. The NBO analysis provides a consistent picture of the bonding in this entire family of complexes in terms of charge transfer (CT) interactions, showing the close correlation of these interactions with the van der Waals penetration distance and dissociation energy of the complex. Contrary to previous studies based on the Kitaura--Morokuma analysis, we find a clear theoretical distinction between H-bonded and non-H-bonded complexes based on the strength of CT interactions. Charge transfer is generally stronger in H-bonded than in non-H-bonded complexes. It plays an intermediate role in non-H-bonded CO2 complexes which have been studied experimentally. However, the internal rotation barrier (1 kcal mol-1) of the H2OxxxCO2 complex is found to be primarily of electrostatic origin with only a small (π-type) CT contribution. The role of electrostatic interactions, effect of electron correlation, and comparison of theory with experiment are also discussed

  5. Imaging of Orbital Infections

    Directory of Open Access Journals (Sweden)

    Seyed Hassan Mostafavi

    2010-05-01

    Full Text Available Preseptal and orbital cellulitis occur more commonly in children than adults. The history and physical examination are crucial in distinguishing between preseptal and orbital cellulitis. The orbital septum delineates the anterior eyelid soft tissues from the orbital soft tissue. Infections anterior to the orbital septum are classified as preseptal cellulitis and those posterior to the orbital septum are termed orbital cellulitis. "nRecognition of orbital involvement is important not only because of the threatened vision loss associated with orbital cellulitis but also because of the potential for central nervous system complications including cavernous sinus thrombosis, meningitis, and death. "nOrbital imaging should be obtained in all patients suspected of having orbital cellulitis. CT is preferred to MR imaging, as the orbital tissues have high con-trast and the bone can be well visualized. Orbital CT scanning allows localization of the disease process to the preseptal area, the extraconal or intraconal fat, or the subperiosteal space. Axial CT views allow evaluation of the medial orbit and ethmoid sinuses, whereas coronal scans image the orbital roof and floor and the frontal and maxillary sinuses. If direct coronal imaging is not possible, reconstruction of thin axial cuts may help the assessment of the orbital roof and floor. Potential sources of orbital cellulitis such as sinusitis, dental infection, and facial cellulitis are often detectable on CT imaging. "nIn this presentation, the imaging considerations of the orbital infections; including imaging differentiation criteria of all types of orbital infections are reviewed.

  6. Wide double stars - I. The spectroscopic binaries: Double stars with wide separations in the AGK3 - I. The components that are themselves spectroscopic binaries

    CERN Document Server

    Halbwachs, Jean-Louis; Udry, Stéphane

    2011-01-01

    Wide binaries are tracers of the gravity field of the Galaxy, but their study requires some caution. A large list of common proper motion stars selected from the AGK3 were monitored with the CORAVEL spectrovelocimeter, in order to prepare a sample of physical binaries with very wide separations. Sixty-six stars received special attention, since their RV seemed to be variable. These stars were monitored over several years in order to derive the elements of their spectroscopic orbits. In addition, 10 of them received accurate RV measurements from the SOPHIE spectrograph of the T193 telescope at the Observatory of Haute-Provence. For deriving the orbital elements of double-lined spectroscopic binaries (SB2), a new method was applied, which assumed that the RV of blended measurements are linear combinations of the RV of the components. Thirteen SB2 orbits were thus calculated. The orbital elements were eventually obtained for 52 spectroscopic binaries (SB), two of them making a triple system. Forty SB received th...

  7. The analysis of spin and spin-orbit coupling in quantum and classical physics by quaternions

    International Nuclear Information System (INIS)

    It is shown that quaternions offer a simple elegant description of spin of a single particle, perhaps superior to that of conventional quantum mechanics. The spin operators are Ssub(x) = (1/2)i, Ssub(y) = (1/2)j and Ssub(z) = (1/2)k (in units where (h/2π) = 1). Quaternion angular functions Z+-sub(j), msub(j) are given, which are explicit expressions for |l,s,j,msub(j)> in terms of the states |l,s,msub(l),msub(s)>. Use of these Z+-functions offers an elegant analysis of: (i) the relativistic hydrogen atom; (ii) problems in classical physics, such as the wave equation. Consideration is given to a speculation that there is simultaneous 'reality' of all three components of spin. (author)

  8. Binary and Millisecond Pulsars

    Directory of Open Access Journals (Sweden)

    Lorimer Duncan R.

    2008-11-01

    Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M_⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44 orbit around an unevolved companion.

  9. Binary and Millisecond Pulsars

    CERN Document Server

    Lorimer, D R

    2008-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 solar masses, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e=0.44) orbit around an unevolved companion.

  10. Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in supergiant fast X-ray transient and classical supergiant X-ray binaries

    Science.gov (United States)

    Giménez-García, A.; Shenar, T.; Torrejón, J. M.; Oskinova, L.; Martínez-Núñez, S.; Hamann, W.-R.; Rodes-Roca, J. J.; González-Galán, A.; Alonso-Santiago, J.; González-Fernández, C.; Bernabeu, G.; Sander, A.

    2016-06-01

    Context. Classical supergiant X-ray binaries (SGXBs) and supergiant fast X-ray transients (SFXTs) are two types of high-mass X-ray binaries (HMXBs) that present similar donors but, at the same time, show very different behavior in the X-rays. The reason for this dichotomy of wind-fed HMXBs is still a matter of debate. Among the several explanations that have been proposed, some of them invoke specific stellar wind properties of the donor stars. Only dedicated empiric analysis of the donors' stellar wind can provide the required information to accomplish an adequate test of these theories. However, such analyses are scarce. Aims: To close this gap, we perform a comparative analysis of the optical companion in two important systems: IGR J17544-2619 (SFXT) and Vela X-1 (SGXB). We analyze the spectra of each star in detail and derive their stellar and wind properties. As a next step, we compare the wind parameters, giving us an excellent chance of recognizing key differences between donor winds in SFXTs and SGXBs. Methods: We use archival infrared, optical and ultraviolet observations, and analyze them with the non-local thermodynamic equilibrium (NLTE) Potsdam Wolf-Rayet model atmosphere code. We derive the physical properties of the stars and their stellar winds, accounting for the influence of X-rays on the stellar winds. Results: We find that the stellar parameters derived from the analysis generally agree well with the spectral types of the two donors: O9I (IGR J17544-2619) and B0.5Iae (Vela X-1). The distance to the sources have been revised and also agree well with the estimations already available in the literature. In IGR J17544-2619 we are able to narrow the uncertainty to d = 3.0 ± 0.2 kpc. From the stellar radius of the donor and its X-ray behavior, the eccentricity of IGR J17544-2619 is constrained to e< 0.25. The derived chemical abundances point to certain mixing during the lifetime of the donors. An important difference between the stellar winds of the

  11. Discovery of the neutron star spin and orbital period from the Be/X-ray binary IGR J05414-6858 in the LMC

    CERN Document Server

    Sturm, R; Rau, A; Bartlett, E S; Zhang, X -L; Schady, P; Pietsch, W; Greiner, J; Coe, M J; Udalski, A

    2012-01-01

    The number of known Be/X-ray binaries in the Large Magellanic Cloud is small compared to the observed population of the Galaxy or the Small Magellanic Cloud. The discovery of a system in outburst provides the rare opportunity to measure its X-ray properties in detail. IGR J05414-6858 was serendipitously found in outburst with the Swift satellite in August 2011. In order to characterise the system, we analysed the data from a follow-up XMM-Newton target of opportunity observation and investigate the stellar counterpart with photometry and spectroscopy. We modelled the X-ray spectra from the EPIC instruments on XMM-Newton and compared them with Swift archival data. In the X-ray and optical light curves, we searched for periodicities and variability. The optical counterpart was classified using spectroscopy obtained with ESO's Faint Object Spectrograph at NTT. The X-ray spectra as seen in 2011 are relatively hard with a photon index of ~0.3 - 0.4 and show only low absorption. They deviate significantly from earl...

  12. SWIFT OBSERVATIONS OF THE HIGH-MASS X-RAY BINARY IGR J16283-4838 UNVEIL A 288 DAY ORBITAL PERIOD

    Energy Technology Data Exchange (ETDEWEB)

    Cusumano, G.; Segreto, A.; La Parola, V. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, Via U. La Malfa 153, I-90146, Palermo (Italy); D' Aì, A. [Dipartimento di Fisica, Università di Palermo, via Archirafi 36, I-90123, Palermo (Italy); Masetti, N. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129, Bologna (Italy); Tagliaferri, G., E-mail: cusumano@ifc.inaf.it [INAF-Brera Astronomical Observatory, via Bianchi 46, I-23807, Merate (Italy)

    2013-09-20

    We report on the temporal and spectral properties of the high-mass X-ray binary IGR J16283-4838 in the hard X-ray band. We searched the first 88 months of Swift Burst Alert Telescope (BAT) survey data for long-term periodic modulations. We also investigated the broad band (0.2-150 keV) spectral properties of IGR J16283-4838 complementing the BAT dataset with soft X-ray data from the available Swift-XRT pointed observations. The BAT light curve of IGR J16283-4838 revealed a periodic modulation at P{sub o} = 287.6 ± 1.7 days (with a significance higher than 4 standard deviations). The profile of the light curve folded at P{sub o} shows a sharp peak lasting ∼12 days over a flat plateau. The long-term light curve also shows a ∼300 day interval of prolonged enhanced emission. The observed phenomenology suggests that IGR J16283-4838 has a Be nature, where the narrow periodic peaks and the ∼300 day outburst can be interpreted as Type I and Type II outbursts, respectively. The broad band 0.2-150 keV spectrum can be described with an absorbed power-law and a steepening in the BAT energy range.

  13. Precise radial velocities of giant stars IX. HD 59686 Ab: a massive circumstellar planet orbiting a giant star in a ~13.6 au eccentric binary system

    CERN Document Server

    Ortiz, Mauricio; Trifonov, Trifon; Quirrenbach, Andreas; Mitchell, David; Nowak, Grzegorz; Buenzli, Esther; Zimmerman, Neil; Bonnefoy, Mickael; Skemer, Andy; Defrère, Denis; Lee, Man Hoi; Fischer, Debra; Hinz, Philip

    2016-01-01

    Context: For over 12 years, we have carried out a precise radial velocity survey of a sample of 373 G and K giant stars using the Hamilton \\'Echelle Spectrograph at Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims: We aim at detecting and characterizing substellar+stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods: We obtained high precision radial velocity (RV) measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. In order to discriminate between RV variations due to non-radial pulsation or stellar spots we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to further characterize the system, we obtain high-resolution images with LMIRCam at the Large Binocular Telescope. Results: We report the likely discovery of a giant plane...

  14. Galaxy Rotation and Rapid Supermassive Binary Coalescence

    Science.gov (United States)

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-01

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

  15. New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems

    CERN Document Server

    Bluhm, P; Vanzi, L; Soto, M G; Vos, J; Wittenmyer, R A; Olivares, F; Drass, H; Mennickent, R E; Vuckovic, M; Rojo, P; Melo, C H F

    2016-01-01

    We report the discovery of 24 spectroscopic binary companions to giant stars. We fully constrain the orbital solution for 6 of these systems. We cannot unambiguously derive the orbital elements for the remaining stars because the phase coverage is incomplete. Of these stars, 6 present radial velocity trends that are compatible with long-period brown dwarf companions.The orbital solutions of the 24 binary systems indicate that these giant binary systems have a wide range in orbital periods, eccentricities, and companion masses. For the binaries with restricted orbital solutions, we find a range of orbital periods of between $\\sim$ 97-1600 days and eccentricities of between $\\sim$ 0.1-0.4. In addition, we studied the metallicity distribution of single and binary giant stars. We computed the metallicity of a total of 395 evolved stars, 59 of wich are in binary systems. We find a flat distribution for these binary stars and therefore conclude that stellar binary systems, and potentially brown dwarfs, have a diffe...

  16. Red Giants in Eclipsing Binaries as a Benchmark for Asteroseismology

    Science.gov (United States)

    Rawls, Meredith L.

    2016-04-01

    Red giants with solar-like oscillations are astrophysical laboratories for probing the Milky Way. The Kepler Space Telescope revolutionized asteroseismology by consistently monitoring thousands of targets, including several red giants in eclipsing binaries. Binarity allows us to directly measure stellar properties independently of asteroseismology. In this dissertation, we study a subset of eight red giant eclipsing binaries observed by Kepler with a range of orbital periods, oscillation behavior, and stellar activity. Two of the systems do not show solar-like oscillations at all. We use a suite of modeling tools to combine photometry and spectroscopy into a comprehensive picture of each star's life. One noteworthy case is a double red giant binary. The two stars are nearly twins, but have one main set of solar-like oscillations with unusually low-amplitude, wide modes, likely due to stellar activity and modest tidal forces acting over the 171 day eccentric orbit. Mixed modes indicate the main oscillating star is on the secondary red clump (a core-He-burning star), and stellar evolution modeling supports this with a coeval history for a pair of red clump stars. The other seven systems are all red giant branch stars (shell-H-burning) with main sequence companions. The two non-oscillators have the strongest magnetic signatures and some of the strongest lifetime tidal forces with nearly-circular 20–34 day orbits. One system defies this trend with oscillations and a 19 day orbit. The four long-period systems (>100 days) have oscillations, more eccentric orbits, and less stellar activity. They are all detached binaries consistent with coevolution. We find the asteroseismic scaling laws are approximately correct, but fail the most for stars that are least like the Sun by systematically overestimating both mass and radius. Strong magnetic activity and tidal effects often occur in tandem and act to suppress solar-like oscillations. These red giant binaries offer an

  17. A Massive Pulsar in a Compact Relativistic Binary

    CERN Document Server

    Antoniadis, John; Wex, Norbert; Tauris, Thomas M; Lynch, Ryan S; van Kerkwijk, Marten H; Kramer, Michael; Bassa, Cees; Dhillon, Vik S; Driebe, Thomas; Hessels, Jason W T; Kaspi, Victoria M; Kondratiev, Vladislav I; Langer, Norbert; Marsh, Thomas R; McLaughlin, Maura A; Pennucci, Timothy T; Ransom, Scott M; Stairs, Ingrid H; van Leeuwen, Joeri; Verbiest, Joris P W; Whelan, David G; 10.1126/science.1233232

    2013-01-01

    Many physically motivated extensions to general relativity (GR) predict significant deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar in a 2.46-hr orbit with a 0.172 +/- 0.003 solar mass white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

  18. THE STUDY OF MENTAL MODEL ON N-HEXANE-METHANOL BINARY SYSTEM (THE VALIDATION OF PHYSICAL CHEMISTRY PRACTICUM PROCEDURE

    Directory of Open Access Journals (Sweden)

    Albaiti Albaiti

    2016-04-01

    Full Text Available N-hexane and methanol systen is one example of a binary system that shows the solubility properties of reciprocity. This study aimed to assess the mental model of a n-hexane-methanolbinary system. Interaction at the submicroscopic level between n-hexane and methanol molecules is described in the form of mental model. Penelitian ini menggunakan cloud point method untuk memperoleh data kesetimbangan cair-cair sistem n-heksana-metanol. This study used a cloud point method to obtain data on liquid-liquid equilibrium on the system of n-hexane-methanol. Research data showed the maximum critical temperature (above the consolute temperature of this system was at 42.95 °C with Xmethanol = 0.475 (P= 715 mmHg. Data from the laboratory observations was representedas a symbolic level in the form of the curve of correlation between mole fraction of methanol with temperature in a phase diagram system of n-hexane-methanol. The curve that was formed was asymmetric. It indicated that the solubility of n-hexane in methanol was relatively small compared to the solubility of methanol in n-hexane. Mental model of the binary system of n-hexane-methanol in four curve areasin the form of visualization of the interaction between n-hexane and methanol molecules through London force. In thermodynamics, each component had the same chemical potential inboth phases at equilibrium state. This study results could have a contribution to form a mental model on the student as the prospective chemistry subject teachers.

  19. Merging Compact Binaries in Hierarchical Triple Systems: Resonant Excitation of Binary Eccentricity

    CERN Document Server

    Liu, Bin; Yuan, Ye-Fei

    2015-01-01

    The merging of compact binaries play an important role in astrophysical context. The gravitational waves takes the angular momentum off the merging binary, which makes the orbit of the inner binary shrink. In this work, we study the secular dynamics of merging binary with a small perturber in hierarchical triple systems. From our numerical calculations, we find that the triple system goes through a resonant state between the apsidal precession rates of two orbits during the orbital decay, and the eccentricity of the inner orbit is excited, as well as the corresponding gravita- tional wave frequency. Our numerical results could be understood under the linear approximation of small orbital eccentricities and coplanar configuration. Especially, the resonant condition and the excited eccentricity can be estimated analytically.

  20. Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in supergiant fast X-ray transient and classical supergiant X-ray binaries

    Science.gov (United States)

    Giménez-García, A.; Shenar, T.; Torrejón, J. M.; Oskinova, L.; Martínez-Núñez, S.; Hamann, W.-R.; Rodes-Roca, J. J.; González-Galán, A.; Alonso-Santiago, J.; González-Fernández, C.; Bernabeu, G.; Sander, A.

    2016-06-01

    Context. Classical supergiant X-ray binaries (SGXBs) and supergiant fast X-ray transients (SFXTs) are two types of high-mass X-ray binaries (HMXBs) that present similar donors but, at the same time, show very different behavior in the X-rays. The reason for this dichotomy of wind-fed HMXBs is still a matter of debate. Among the several explanations that have been proposed, some of them invoke specific stellar wind properties of the donor stars. Only dedicated empiric analysis of the donors' stellar wind can provide the required information to accomplish an adequate test of these theories. However, such analyses are scarce. Aims: To close this gap, we perform a comparative analysis of the optical companion in two important systems: IGR J17544-2619 (SFXT) and Vela X-1 (SGXB). We analyze the spectra of each star in detail and derive their stellar and wind properties. As a next step, we compare the wind parameters, giving us an excellent chance of recognizing key differences between donor winds in SFXTs and SGXBs. Methods: We use archival infrared, optical and ultraviolet observations, and analyze them with the non-local thermodynamic equilibrium (NLTE) Potsdam Wolf-Rayet model atmosphere code. We derive the physical properties of the stars and their stellar winds, accounting for the influence of X-rays on the stellar winds. Results: We find that the stellar parameters derived from the analysis generally agree well with the spectral types of the two donors: O9I (IGR J17544-2619) and B0.5Iae (Vela X-1). The distance to the sources have been revised and also agree well with the estimations already available in the literature. In IGR J17544-2619 we are able to narrow the uncertainty to d = 3.0 ± 0.2 kpc. From the stellar radius of the donor and its X-ray behavior, the eccentricity of IGR J17544-2619 is constrained to ephysically characterize them and their spectra. In addition, the orbital parameters of the systems are similar too, with a nearly circular orbit and short

  1. Detecting Eccentric Globular Cluster Binaries with LISA

    OpenAIRE

    Benacquista, M.

    2001-01-01

    The energy carried in the gravitational wave signal from an eccentric binary is spread across several harmonics of the orbital frequency. The inclusion of the harmonics in the analysis of the gravitational wave signal increases the signal-to-noise ratio of the detected signal for binaries whose fundamental frequency is below the galactic confusion-limited noise cut-off. This can allow for an improved angular resolution for sources whose orbital period is greater than 2000 s. Globular cluster ...

  2. Interacting binaries

    CERN Document Server

    Shore, S N; van den Heuvel, EPJ

    1994-01-01

    This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

  3. Physical properties of the pure 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid and its binary mixtures with alcohols

    International Nuclear Information System (INIS)

    Highlights: • Thermo-physical properties of the pure ionic liquid were experimental determined. • Physical properties of binary mixtures (alcohol + ionic liquid) were measured. • From experimental data, excess properties (VE and KS,mE) were calculated. • The excess properties were fitted using the Redlich–Kister equation. • The effect of the ions and temperature on the VE and KS,mE was also discussed. -- Abstract: In this paper, experimental densities, speeds of sound, dynamic viscosities, refractive indices and molar isobaric heat capacities of the pure 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid, [PMpyr][NTf2], are reported as a function of temperature from T = (293.15 to 343.15) K and at atmospheric pressure. From density and refractive index data, the thermal expansion coefficient, molar refractions and molar refractions for the pure ionic liquid were calculated. Besides, a thermal analysis was carried out for the pure ionic liquid using a differential scanning calorimeter. Linear equations were used to fit the density, speed of sound, refractive index and molar isobaric heat capacity data, while the viscosity data were fitted using common equations such as Arrhenius, Vogel−Fulcher−Tamman (VFT), Litovitz, and fluidity. Furthermore, experimental density, speed of sound and refractive index data for binary mixtures with alcohols and their derived properties (excess molar volume, and excess molar isentropic compression) were determined over the whole composition range from T = (298.15, 303.15 and 308.15) K. The excess properties were satisfactorily fitted by Redlich–Kister equation

  4. KEPLER ECLIPSING BINARY STARS. I. CATALOG AND PRINCIPAL CHARACTERIZATION OF 1879 ECLIPSING BINARIES IN THE FIRST DATA RELEASE

    International Nuclear Information System (INIS)

    The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg2 field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD0, P0), morphology type, physical parameters (Teff, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T2/T1, q, fillout factor, and sin i for overcontacts, and T2/T1, (R1 + R2)/a, esin ω, ecos ω, and sin i for detached binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be ∼1.2% across the Kepler field. We further discuss the distribution of binaries as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in eclipsing binary stars.

  5. Is the $\\beta$ Pictoris member GJ3039AB a physical binary? What the rotation periods tell us

    CERN Document Server

    Messina, Sergio; Medhi, Biman J

    2016-01-01

    We have carried out a multi-band photometric monitoring of the close visual binary GJ3039, consisting of a M4 primary and a fainter secondary component, and likely member of the young stellar association $\\beta$ Pictoris (24-Myr old). From our analysis we found that both components are photometric variables and, for the first time, we detected two micro-flare events. We measured from periodogram analysis of the photometric time series two rotation periods P = 3.355d and P = 0.925d, that we could attribute to the brighter GJ3039A and the fainter GJ3039B components, respectively. A comparison of these rotation periods with the period distribution of other $\\beta$ Pictoris members further supports that GJ3039A is a member of this association. We find that also GJ3039B could be a member, but the infrared magnitude differences between the two components taken from the literature and the photometric variability, which is found to be comparable in both stars, suggest that GJ3039B could be a foreground star physicall...

  6. The photometric investigation of the newly discovered W UMa type binary system GSC 03122-02426

    CERN Document Server

    Zhou, X; He, J -J; Zhang, J; Zhang, B

    2016-01-01

    The $B$ $V$ $R_c$ $I_c$ bands light curves of the newly discovered binary system \\astrobj{GSC 03122-02426} are obtained and analyzed using the Wilson-Devinney (W-D) code. The solutions suggest that the mass ratio of the binary system is $q = 2.70$ and the less massive component is $422K$ hotter than the more massive one. We conclude that \\astrobj{GSC 03122-02426} is a W-subtype shallow contact (with a contact degree of $f = 15.3\\,\\%$) binary system. It may be a newly formed contact binary system which is just under geometrical contact and will evolve to be a thermal contact binary system. The high orbital inclination ($i = 81.6^{\\circ}$) implies that \\astrobj{GSC 03122-02426} is a total eclipsing binary system and the photometric parameters obtained by us are quite reliable. We also estimate the absolute physical parameters of the two components in \\astrobj{GSC 03122-02426}, which will provide fundamental information for the research of contact binary systems. The formation and evolutionary scenario of \\astro...

  7. Orbit analysis

    International Nuclear Information System (INIS)

    The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators

  8. Orbit analysis

    Energy Technology Data Exchange (ETDEWEB)

    Michelotti, L.

    1995-01-01

    The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators.

  9. Milankovitch Cycles of Terrestrial Planets in Binary Star Systems

    CERN Document Server

    Forgan, Duncan H

    2016-01-01

    The habitability of planets in binary star systems depends not only on the radiation environment created by the two stars, but also on the perturbations to planetary orbits and rotation produced by the gravitational field of the binary and neighbouring planets. Habitable planets in binaries may therefore experience significant perturbations in orbit and spin. The direct effects of orbital resonances and secular evolution on the climate of binary planets remain largely unconsidered. We present latitudinal energy balance modelling of exoplanet climates with direct coupling to an N Body integrator and an obliquity evolution model. This allows us to simultaneously investigate the thermal and dynamical evolution of planets orbiting binary stars, and discover gravito-climatic oscillations on dynamical and secular timescales. We investigate the Kepler-47 and Alpha Centauri systems as archetypes of P and S type binary systems respectively. In the first case, Earthlike planets would experience rapid Milankovitch cycle...

  10. Distinguishing Between Formation Channels for Binary Black Holes with LISA

    CERN Document Server

    Breivik, Katelyn; Larson, Shane L; Kalogera, Vassiliki; Rasio, Frederic A

    2016-01-01

    The recent detections of GW150914 and GW151226 imply an abundance of stellar-mass binary-black-hole mergers in the local universe. While ground-based gravitational-wave detectors are limited to observing the final moments before a binary merges, space-based detectors, such as the Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where such systems may still encode information about their formation histories. In particular, the orbital eccentricity of binary black holes in the LISA frequency band can be used discriminate between binaries formed in isolation in galactic fields, and those formed in dense stellar environments such as globular clusters. In this letter, we explore the differences in orbital eccentricities of binary black hole populations as they evolve through the LISA frequency band. Overall we find that there are three distinct populations of orbital eccentricities discernible by LISA. We show that, depending on gravitational-wave frequency, anywhere fro...

  11. Twin Binaries: Studies of Stability, Mass Transfer, and Coalescence

    CERN Document Server

    Lombardi, James C; Dooley, Katherine L; Gearity, Kyle; Kalogera, Vassiliki; Rasio, Frederic A

    2010-01-01

    Motivated by suggestions that binaries with almost equal-mass components ("twins") play an important role in the formation of double neutron stars and may be rather abundant among binaries, we study the stability of synchronized close and contact binaries with identical components in circular orbits. In particular, we investigate the dependency of the innermost stable circular orbit on the core mass, and we study the coalescence of the binary that occurs at smaller separations. For twin binaries composed of convective main-sequence stars, subgiants, or giants with low mass cores (M_c ~0.15M), we find that stable contact configurations exist at all separations down to the Roche limit, when mass shedding through the outer Lagrangian points triggers a coalescence of the envelopes and leaves the cores orbiting in a central tight binary. We discuss the implications of our results to the formation of binary neutron stars.

  12. Cassini states for black hole binaries

    OpenAIRE

    Correia, Alexandre C. M.

    2015-01-01

    Cassini states correspond to the equilibria of the spin axis of a body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black hole binary systems base...

  13. 低质量X射线双星的长期监测和吸积物理%Monitoring Observations of Low Mass X-ray Binary and Accretion Physics

    Institute of Scientific and Technical Information of China (English)

    闫震

    2011-01-01

    brightehard states are permitted by physics and can be observed in the Galactic X-ray binaries, and these phenomena might have been observed in ultra-luminous X-ray sources in nearby galaxies. We then have statistically studied the rise timescales of outbursts in low-mass X-ray binary transients during the past more than ten years. The results shows the rise timescales are nearly constant with large scatter in different outbursts, which supports the positive correlation between the rate-of-increase of luminosity and peak luminosity. We also found that the mean value of rise timescale is about several days and weakly correlates with the orbital period. Our results indicate that the rise timescale may correspond to the viscous timescale at some outer radius in the accretion disc, and somehow correlates with the size of the accretion disc.We have also performed the analysis of the multi-wavelength observations (including ultraviolet, optical and X-ray) cross the state transition during the 2010 outburst of GX 339-4 by Swift. We found that the UV flux positively correlates with the 0.6-10 keV X-ray in a form of fuv ∝ f0.52±0.04 X, and 10 days before the hard-to-soft state transition, UV flux shows a rapid drop, during which the X-ray flux still increases. We argued that the UV emission was dominated by jet during this outburst, and the optically thick spectrum can extend to higher frequency in a more powerful jet in a hard state. The drop in UV flux indicates the jet starts to switch off before hard-to-soft state transition, and could be used to predict the occurrence of the hard-to-soft transition.%本论文基于X射线空间卫星的多波段监测数据,研究明亮的低质量X射线双星的X射线能谱的演化和态跃迁过程,暂现源在爆发过程中的一些性质以及不同波段的光度的演化和相关关系.暂现源的爆发所涉及的光度范围很大,这对于研究吸积物理具有不可比拟的重要性,可以研究不同的吸积率下的吸积

  14. Physics and Initial Data for Multiple Black Hole Spacetimes

    CERN Document Server

    Bonning, E; Neilsen, D W; Matzner, R A; Bonning, Erin; Marronetti, Pedro; Neilsen, David; Matzner, Richard

    2003-01-01

    An orbiting black hole binary will generate strong gravitational radiation signatures, making these binaries important candidates for detection in gravitational wave observatories. The gravitational radiation is characterized by the orbital parameters, including the frequency and separation at the inner-most stable circular orbit (ISCO). One approach to estimating these parameters relies on a sequence of initial data slices that attempt to capture the physics of the inspiral. Using calculations of the binding energy, several authors have estimated the ISCO parameters using initial data constructed with various algorithms. In this paper we examine this problem using conformally Kerr-Schild initial data. We present convergence results for our initial data solutions, and give data from numerical solutions of the constraint equations representing a range of physical configurations. In a first attempt to understand the physical content of the initial data, we find that the Newtonian binding energy is contained in ...

  15. Magnetic braking in ultracompact binaries

    CERN Document Server

    Farmer, Alison

    2010-01-01

    Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically coupled winds could in fact lead to substantial additional angular momentum losses. We remark that the scaling relations often invoked for the relative importance of gravitational and magnetic braking do not apply, and instead use simple non-empirical expressions for the braking rates. In order to remove significant angular momentum, the wind must be tied to field lines anchored in one of the binary's component stars; uncertainties remain as to the driving mechanism for such a wind. In the case of white dwarf accretors, we find that magnetic braking can potentially remove angular momentum on comparable or even shorter timescales than gravitational waves over a large range in orbital period. We present such a solution for the 17-minute binary AM CVn itself which a...

  16. How I Learned to Stop Worrying and Love Eclipsing Binaries

    OpenAIRE

    Moe, Maxwell

    2015-01-01

    Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational waves. However, the formation mechanism, intrinsic frequency, and evolutionary processes of B-type binaries are poorly understood. As of 2012, the binary statistics of massive stars had not been measured at low metallicities, extreme mass ratios, or intermediate orbital ...

  17. Nonspinning searches for spinning binaries in ground-based detector data: Amplitude and mismatch predictions in the constant precession cone approximation

    CERN Document Server

    Brown, D; O'Shaughnessy, R

    2012-01-01

    Current searches for compact binary mergers by ground-based gravitational-wave detectors assume for simplicity the two bodies are not spinning. If the binary contains compact objects with significant spin, then this can reduce the sensitivity of these searches, particularly for black hole--neutron star binaries. In this paper we investigate the effect of neglecting precession on the sensitivity of searches for spinning binaries using non-spinning waveform models. We demonstrate that in the sensitive band of Advanced LIGO, the angle between the binary's orbital angular momentum and its total angular momentum is approximately constant. Under this \\emph{constant precession cone} approximation, we show that the gravitational-wave phasing is modulated in two ways: a secular increase of the gravitational-wave phase due to precession and an oscillation around this secular increase. We show that this secular evolution occurs in precisely three ways, corresponding to physically different apparent evolutions of the bin...

  18. An Observational Study of Algol-Type Binary System

    Science.gov (United States)

    Zhang, J.

    2015-01-01

    The Algol-Type binary systems are a subtype of binary systems. Their unique semi-detached structure leads to have abundant physical phenomena, including the dramatically distorted donor star, strong magnetic activities, various ways of mass transfer, the evolution stage quite different from that of single stars, and specific formation tracks. In this paper, we introduce the fundamental physics of light curves, as well as the models or programs used in the past. We show the influence of different parameters on the light curves, including the inclination, temperature, abundance, surface gravity, the third light, radius, orbital eccentricity, and the argument of periastron. Based on the current catalog of Algols, we investigate their statistic characteristics. We observe three Algols and analyze the data in detail. The results are as follows: (1)Our statistical analyses of Algols support the previous suggestion that most of the detached component stars are main sequence stars. The distribution of the mass ratio agrees to our calculated critical value of the mass ratio for Algols. We suggest that there could be a lower limit of the radius ratio. We also show that there are good correlations among the temperature, luminosity, radius, and the mass of the component stars. (2) The binary FG Gem is observed, and the data are analyzed. Based on the solutions of large combinations of the temperature and luminosity, we use a new age-comparing method to show that the FG Gem is a semi-detached system, and a new temperature-searching method to get a better estimate of the temperature of the detached component star. We suggest that a combination of the intermittent mass flow and the continuous magnetic braking can explain its orbital period change. (3) Taking the VV Vir as an example, we discuss some properties of the mass flow in a semi-detached binary. Some of them can reflect the common characteristics of the mass flows in the Algol systems, e.g., the radius of the mass flow is

  19. Infalling clouds on to supermassive black hole binaries - II. Binary evolution and the final parsec problem

    CERN Document Server

    Goicovic, Felipe G; Cuadra, Jorge; Stasyszyn, Federico

    2016-01-01

    The formation of massive black hole binaries (MBHBs) is an unavoidable outcome of galaxy evolution via successive mergers. However, the mechanism that drives their orbital evolution from parsec separations down to the gravitational wave (GW) dominated regime is poorly understood and their final fate is still unclear. If such binaries are embedded in gas-rich and turbulent environments, as observed in remnants of galaxy mergers, the interaction with gas clumps (such as molecular clouds) may efficiently drive their orbital evolution. Using numerical simulations, we test this hypothesis by studying the dynamical evolution of an equal-mass, circular MBHB accreting infalling molecular clouds. We investigate different orbital configurations, modelling a total of 13 systems to explore different possible pericentre distances and relative inclinations of the cloud-binary encounter. We show that the evolution of the binary orbit is dominated by the exchange of angular momentum through gas accretion during the first sta...

  20. Binary Popldation Synthcsis Study

    Institute of Scientific and Technical Information of China (English)

    HAN Zhanwen

    2011-01-01

    Binary population synthesis (BPS), an approach to evolving millions of stars (including binaries) simultaneously, plays a crucial role in our understanding of stellar physics, the structure and evolution of galaxies, and cosmology. We proposed and developed a BPS approach, and used it to investigate the formation of many peculiar stars such as hot subdwarf stars, progenitors of type la supernovae, barium stars, CH stars, planetary nebulae, double white dwarfs, blue stragglers, contact binaries, etc. We also established an evolution population synthesis (EPS) model, the Yunnan Model, which takes into account binary interactions for the first time. We applied our model for the origin of hot subdwarf stars in the study of elliptical galaxies and explained their far-UV radiation.

  1. Planet Scattering Around Binaries: Ejections, Not Collisions

    CERN Document Server

    Smullen, Rachel A; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Asid...

  2. New binary solid dispersion of Indomethacin and croscarmellose sodium: Physical characterization and in-vitro dissolution enhancement

    Directory of Open Access Journals (Sweden)

    Silvina Castro

    2012-12-01

    Full Text Available Solid dispersions (SDx containing Indomethacin (IND, a poorly water-soluble drug, and the disintegrant excipient sodium croscarmellose (SC were prepared by a co-drying method and characterized by Infrared spectroscopy (FT-IR, X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electronmicroscopy (SEM. An FT-IR analysis performed on IND-SC solid dispersion and their physical mixtures indicated that IND does not interact with SC in the solid state. An analysis of the information produced by DSC, XRD, and SEM confirmed that the crystalline α-form of IND was homogeneously incorporated into SDx. IND release from SDx was significantly greater than that from its corresponding physical mixtures with the high homogeneous molecular dispersion and the crystalline modification of IND appearing to be the cause. This behavior may have a beneficial effect on the biopharmaceutical performance of this drug.

  3. Winds in Collision: high-energy particles in massive binary systems

    CERN Document Server

    Dougherty, S M; Dougherty, Sean M.; Pittard, Julian M.

    2006-01-01

    High-resolution radio observations have revealed that non-thermal radio emission in WR stars arises where the stellar wind of the WR star collides with that of a binary companion. These colliding-wind binary (CWB) systems offer an important laboratory for investigating the underlying physics of particle acceleration. Hydrodynamic models of the binary stellar winds and the wind-collision region (WCR) that account for the evolution of the electron energy spectrum, largely due to inverse Compton cooling, are now available. Radiometry and imaging obtained with the VLA, MERLIN, EVN and VLBA provide essential constraints to these models. Models of the radio emission from WR146 and WR147 are shown, though these very wide systems do not have defined orbits and hence lack a number of important model parameters. Multi-epoch VLBI imaging of the archetype WR+O star binary WR140 through a part of its 7.9-year orbit has been used to define the orbit inclination, distance and the luminosity of the companion star to enable t...

  4. Extrasolar Binary Planets I: Formation by tidal capture during planet-planet scattering

    CERN Document Server

    Ochiai, H; Ida, S

    2014-01-01

    We have investigated i) the formation of gravitationally bounded pairs of gas-giant planets (which we call "binary planets") from capturing each other through planet-planet dynamical tide during their close encounters and ii) the following long-term orbital evolution due to planet-planet and planet-star {\\it quasi-static} tides. For the initial evolution in phase i), we carried out N-body simulations of the systems consisting of three jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing and this fraction is almost independent of the initial stellarcentric semi-major axes of the planets, while ejection and merging rates sensitively depend on the semi-major axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by ...

  5. Properties of planets in binary systems. The role of binary separation

    OpenAIRE

    Desidera, S.; Barbieri, M.

    2006-01-01

    The statistical properties of planets in binaries were investigated. Any difference to planets orbiting single stars can shed light on the formation and evolution of planetary systems. As planets were found around components of binaries with very different separation and mass ratio, it is particularly important to study the characteristics of planets as a function of the effective gravitational influence of the companion. A compilation of planets in binary systems was made; a search for compa...

  6. Spin supplementary conditions for spinning compact binaries

    CERN Document Server

    Mikóczi, Balázs

    2016-01-01

    We consider the different spin supplementary conditions (SSC) for a spinning compact binary with the leading-order spin-orbit (SO) interaction. The Lagrangian of the binary system can be constructed but it is acceleration-dependent in two cases of SSC. We rewrite the generalized Hamiltonian formalism proposed by Ostrogradsky and compute the conservative quantities and the dissipative part of relative motion during the gravitational radiation of each SSCs. We give the orbital elements and observed quantities of the SO dynamics, for instance the energy and the orbital angular momentum losses and waveforms and discuss their SSC dependence.

  7. Binaries in the Hipparcos data: Keep digging

    OpenAIRE

    Pourbaix, D.; Jancart, S.; Jorissen, A.

    2004-01-01

    Among the 120 000 objects in the Hipparcos catalogue, only 235 were fitted with an orbital model. Besides these 235 original astrometric binaries, most Hipparcos entries with a known spectroscopic orbit (extrasolar planet or stellar companion) have now been re-processed, as part of the on-going construction of the 9th Catalogue of Spectroscopic Binary Orbits (SB9, available at http://sb9.astro.ulb.ac.be). The pitfalls and successes of this re-processing are discussed in various contexts, like...

  8. Space-based Microlens Parallax Observation As a Way to Resolve the Severe Degeneracy between Microlens-parallax and Lens-orbital Effect

    CERN Document Server

    Han, C; Lee, C -U; Gould, A; Bozza, V; Szymański, M K; Soszyński, I; Skowron, J; Mróz, P; Poleski, R; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Wyrzykowski, Ł; Pawlak, M; Albrow, M D; Chung, S -J; Kim, S -L; Cha, S -M; Jung, Y K; Kim, D -J; Lee, Y; Park, B -G; Ryu, Y -H; Shin, I -G; Yee, J C

    2016-01-01

    In this paper, we demonstrate the severity of the degeneracy between the microlens-parallax and lens-orbital effects by presenting the analysis of the gravitational binary-lens event OGLE-2015-BLG-0768. Despite the obvious deviation from the model based on the the linear observer motion and the static binary, it is found that the residual can be almost equally well explained by either the parallactic motion of the Earth or the rotation of the binary lens axis, resulting in the severe degeneracy between the two effects. We show that the degeneracy can be readily resolved with the additional data provided by space-based microlens parallax observations. Enabling to distinguish between the two higher-order effects, space-based microlens parallax observations will make it possible not only to accurately determine the physical lens parameters but also to further constrain the orbital parameters of binary lenses.

  9. White-light Flares on Close Binaries Observed with Kepler

    Science.gov (United States)

    Gao, Qing; Xin, Yu; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

    2016-06-01

    Based on Kepler data, we present the results of a search for white light flares on 1049 close binaries. We identify 234 flare binaries, of which 6818 flares are detected. We compare the flare-binary fraction in different binary morphologies (“detachedness”). The result shows that the fractions in over-contact and ellipsoidal binaries are approximately 10%–20% lower than those in detached and semi-detached systems. We calculate the binary flare activity level (AL) of all the flare binaries, and discuss its variations along the orbital period (P orb) and rotation period (P rot, calculated for only detached binaries). We find that the AL increases with decreasing P orb or P rot, up to the critical values at P orb ∼ 3 days or P rot ∼ 1.5 days, and thereafter the AL starts decreasing no matter how fast the stars rotate. We examine the flaring rate as a function of orbital phase in two eclipsing binaries on which a large number of flares are detected. It appears that there is no correlation between flaring rate and orbital phase in these two binaries. In contrast, when we examine the function with 203 flares on 20 non-eclipse ellipsoidal binaries, bimodal distribution of amplitude-weighted flare numbers shows up at orbital phases 0.25 and 0.75. Such variation could be larger than what is expected from the cross section modification.

  10. Physical Properties of Fireball-Producing Earth-Impacting Meteoroids and Orbit Determination through Shadow Calibration of the Buzzard Coulee Meteorite Fall

    Science.gov (United States)

    Milley, Ellen Palesa

    The physical properties of the meteoroid population were investigated through combining data from a number of fireball camera networks. PE values, as a measure of meteoroid strength, were calculated and linked with other observational criteria (Tisserand parameter, meteor shower identification). The historic divisions for fireball types based on the PE criterion were not observed in the large data set, but a correlation with source region was recognized. Meteor showers demonstrated different amounts of variation in PE values potentially related to the materials found in each parent comet. The trajectory and pre-fall orbit for the Buzzard Coulee meteoroid were determined through the calibration of shadows cast by the fireball. The method of using shadows to triangulate a trajectory was developed and evaluated. The best fit trajectory was coupled with an initial velocity of 18.0 km/s to compute the heliocentric orbit. Buzzard Coulee fell from a modestly inclined near-Earth Apollo orbit. It is the 12th fallen meteorite to be associated with an orbit.

  11. Discs in misaligned binary systems

    Science.gov (United States)

    Rawiraswattana, Krisada; Hubber, David A.; Goodwin, Simon P.

    2016-08-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-alignment processes, which tend to misalign the components. The alignment process dominates in systems with misalignment angle near 90°, while the anti-alignment process dominates in systems with the misalignment angle near 0° or 180°. This means that highly misaligned systems will become more aligned but slightly misaligned systems will become more misaligned.

  12. Detection of gravity modes in the massive binary V380 Cyg from Kepler spacebased photometry and high-resolution spectroscopy

    CERN Document Server

    Tkachenko, A; Pavlovski, K; Southworth, J; Degroote, P; Debosscher, J; Still, M; Bryson, S; Molenberghs, G; Bloemen, S; de Vries, B L; Hrudkova, M; Lombaert, R; Neyskens, P; Papics, P I; Raskin, G; Van Winckel, H; Morris, R L; Sanderfer, D T; Seader, S E

    2012-01-01

    We report the discovery of low-amplitude gravity-mode oscillations in the massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space photometry and 5 months of high-resolution high signal-to-noise spectroscopy. The new data are of unprecedented quality and allowed to improve the orbital and fundamental parameters for this binary. The orbital solution was subtracted from the photometric data and led to the detection of periodic intrinsic variability with frequencies of which some are multiples of the orbital frequency and others are not. Spectral disentangling allowed the detection of line-profile variability in the primary. With our discovery of intrinsic variability interpreted as gravity mode oscillations, V380 Cyg becomes an important laboratory for future seismic tuning of the near-core physics in massive B-type stars.

  13. New orbits based on speckle interferometry at SOAR

    CERN Document Server

    Tokovinin, Andrei

    2016-01-01

    Orbits of 55 visual binary stars are computed using recent speckle interferometry data from the SOAR telescope: 33 first-time orbits and 22 revisions of previous orbit calculations. The orbital periods range from 1.4 to 370 years, the quality of orbits ranges from definitive to preliminary and tentative. Most binaries consist of low-mass dwarfs and have short periods (median period 31 years). The dynamical parallaxes and masses are evaluated and compared to the Hipparcos parallaxes. Using differential speckle photometry, binary components are placed on the color-magnitude diagram.

  14. The Massive Wolf-Rayet Binary HDE318016 (=WR 98)

    CERN Document Server

    Gamen, R C; Gamen, Roberto C.; Niemela, Virpi S.

    2002-01-01

    We present the discovery of OB type absorption lines superimposed to the emission line spectrum, and the first double-lined orbital elements for the massive Wolf-Rayet binary HDE 318016 (=WR 98), a spectroscopic binary in a circular orbit with a period of 47.825 days. The semiamplitudes of the orbital motion of the emission lines differ from line to line, indicating mass ratios between 1 and 1.7 for MWR/MOB.

  15. LASIP-III, a generalized processor for standard interface files. [For creating binary files from BCD input data and printing binary file data in BCD format (devised for fast reactor physics codes)

    Energy Technology Data Exchange (ETDEWEB)

    Bosler, G.E.; O' Dell, R.D.; Resnik, W.M.

    1976-03-01

    The LASIP-III code was developed for processing Version III standard interface data files which have been specified by the Committee on Computer Code Coordination. This processor performs two distinct tasks, namely, transforming free-field format, BCD data into well-defined binary files and providing for printing and punching data in the binary files. While LASIP-III is exported as a complete free-standing code package, techniques are described for easily separating the processor into two modules, viz., one for creating the binary files and one for printing the files. The two modules can be separated into free-standing codes or they can be incorporated into other codes. Also, the LASIP-III code can be easily expanded for processing additional files, and procedures are described for such an expansion. 2 figures, 8 tables.

  16. Coalescing binaries and Doppler experiments

    OpenAIRE

    Vecchio, A.; Bertotti, B.; Iess, L.

    1997-01-01

    We discuss the sensitivity of the CASSINI experiments to gravitational waves emitted by the in-spiral of compact binaries. We show that the maximum distance reachable by the instrument is $\\sim 100$ Mpc. In particular, CASSINI can detect massive black hole binaries with chirp mass $\\simgt 10^6 \\Ms$ in the Virgo Cluster with signal-to-noise ratio between 5 and 30 and possible compact objects of mass $\\simgt 30 \\Ms$ orbiting the massive black hole that our Galactic Centre is likely to harbour.

  17. Quantum simulation of 2d topological physics using orbital-angular-momentum-carrying photons in a 1d array of cavities

    CERN Document Server

    Luo, Xi-Wang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

    2015-01-01

    Orbital angular momentum (OAM) of light is a fundamental optical degree of freedom that has recently motivated much exciting research in diverse fields ranging from optical communication to quantum information. We show for the first time that it is also a unique and valuable resource for quantum simulation, by demonstrating theoretically how \\emph{2d} topological physics can be simulated in a \\emph{1d} array of optical cavities using OAM-carrying photons. Remarkably, this newly discovered application of OAM states not only reduces required physical resources but also increases feasible scale of simulation. By showing how important topics such as edge-state transport and topological phase transition can be studied in a small simulator with just a few cavities ready for immediate experimental exploration, we demonstrate the prospect of photonic OAM for quantum simulation which can have a significant impact on the research of topological physics.

  18. Tomographic Separation of Spectra of O-Type Binary Systems

    Science.gov (United States)

    Penny, L. R.

    1997-07-01

    Knowledge about the individual components of O-type binaries is difficult to obtain because of the severe line blending present in their spectra. An important new method is Doppler tomography, an iterative scheme that uses a set of orbital phase distributed spectra and both radial velocity curves to reconstruct the individual component spectra (see Bagnuolo, Gies & Wiggs 1992, ApJ, 385, 708). These individual spectra can then be analyzed to determine various physical properties of the stars. The spectral types and luminosity classes obtained provide indicators of the temperatures and gravities. The individual projected rotational velocities can be used to test for rotational synchronization of the orbit or rapid spin-up due to mass transfer. For stars that are cluster members, an estimate of the magnitude difference together with the combined absolute magnitude results in individual luminosity estimates. Finally, it is possible to search for abundance differences due to mass transfer or loss. Here I present results of a program of Doppler tomography of O-binaries observed with the International Ultraviolet Explorer (IUE). I describe cross-correlation methods that use narrow-lined spectral templates to obtain precise radial velocities and orbital velocity curves which are used in the tomography algorithm. I present results for six systems: DH Cep, HD 165052, HD 93403, HD93205, HD 149404, and HD 152248. (SECTION: Dissertation Summaries)

  19. The Population of Viscosity- and Gravitational Wave-Driven Supermassive Black Hole Binaries Among Luminous AGN

    CERN Document Server

    Haiman, Zoltán; Menou, Kristen

    2009-01-01

    Supermassive black hole binaries (SMBHBs) in galactic nuclei are thought to be a common by-product of major galaxy mergers. We use simple disk models for the circumbinary gas and for the binary-disk interaction to follow the orbital decay of SMBHBs with a range of total masses (M) and mass ratios (q), through physically distinct regions of the disk, until gravitational waves (GWs) take over their evolution. Prior to the GW-driven phase, the viscous decay is in the stalled "secondary-dominated" regime. SMBHBs spend a non-negligible fraction of 10^7 years at orbital periods t_var between a day and a year. A dedicated optical or X-ray survey could identify coalescing SMBHBs statistically, as a population of periodically variable quasars, whose abundance N_var is proportional to t_var^alpha, in a range of periods t_var around tens of weeks. SMBHBs with M < 10^7 M_sun, with 0.5 < alpha < 1.5, would probe the physics of viscous orbital decay, whereas the detection of a population of higher-mass binaries, w...

  20. Binary black hole late inspiral: Simulations for gravitational wave observations

    CERN Document Server

    Baker, J G; Choi, D I; Kelly, B J; Koppitz, M; McWilliams, S T; Van Meter, J R; Baker, John G.; Centrella, Joan; Choi, Dae-Il; Kelly, Bernard J.; Koppitz, Michael; Meter, James R. van; Williams, Sean T. Mc

    2006-01-01

    Coalescing binary black hole mergers are expected to be the strongest gravitational wave sources for ground-based interferometers, such as the LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Until recently it has been impossible to reliably derive the predictions of General Relativity for the final merger stage, which takes place in the strong-field regime. Recent progress in numerical relativity simulations is, however, revolutionizing our understanding of these systems. We examine here the specific case of merging equal-mass Schwarzschild black holes in detail, presenting new simulations in which the black holes start in the late inspiral stage on orbits with very low eccentricity and evolve for ~1200M through ~7 orbits before merging. We study the accuracy and consistency of our simulations and the resulting gravitational waveforms, which encompass ~14 cycles before merger, and highlight the importance of using frequency (rather than time) to set the physical reference when compari...

  1. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    International Nuclear Information System (INIS)

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  2. Binary star formation: gravitational fragmentation followed by capture

    Science.gov (United States)

    Turner, J. A.; Chapman, S. J.; Bhattal, A. S.; Disney, M. J.; Pongracic, H.; Whitworth, A. P.

    1995-11-01

    intervene, provided the binary components are well matched (i.e. of comparable mass) and the third body is not too massive, such interventions will - more often than not - harden the orbit further. In two appendices we describe the code used in the simulations presented in this and the companion paper, and the tests performed to demonstrate the code's ability to handle the physical processes involved.

  3. Orbital Motion During Gravitational Lensing Events

    CERN Document Server

    Di Stefano, Rosanne

    2014-01-01

    Gravitational lensing events provide unique opportunities to discover and study planetary systems and binaries. Here we build on previous work to explore the role that orbital motion can play in both identifying and learning more about multiple-mass systems that serve as gravitational lenses. We find that a significant fraction of planet-lens and binary-lens light curves are influenced by orbital motion. Furthermore, the effects of orbital motion extend the range of binaries for which lens multiplicity can be discovered and studied. Orbital motion will play an increasingly important role as observations with sensitive photometry, such as those made by the space missions Kepler, Transiting Exoplanet Survey Satellite, (TESS), and WFIRST discover gravitational lensing events. Similarly, the excellent astrometric measurements made possible by GAIA will allow it to study the effects of orbital motion. Frequent observations, such as those made possible with the Korean Microlensing Telescope Network, KMTNet, will al...

  4. Binaries in Transneptunian Resonances: Evidence for Slow Migration of Neptune?

    Science.gov (United States)

    Noll, Keith

    2012-01-01

    A distinguishing feature of trans neptunian objects (TNO) is the high fraction that arc binary. This is particularly true for the Cold Classicals (CC), objects in lowe and low i orbits concentrated between the 3:2 and 2: 1 mean-motion resonances. CCs have other physical markers: red colors, high albedos, and equal-mass binaries. The CCs appear to be a coherent and physically distinct population of planetesimals that has survived to the present with their physical properties relatively unaltered. Their spatial concentration between 39.4 and 47.7 AU has made identification of the CCs as a physical group possible. However, objects that started out as CCs arc almost certainly 1101 limited to this one dynamical niche. We can, therefore, use the measurable physical properties of CCs as tracers of Neptune-driven dynamical mixing in the Kuiper Belt. As Neptune migrated, its mean-motion resonances preceded it into the planetesimal disk. The efficiency of capture into mean motion resonances depends on the smoothness of Neptune's migration and the local population available to be captured. The two strongest resonances, the 3:2 at 39.4 AU and 2: 1 at 47.7 AU, straddle the core repository of the physically distinct CCs, providing a unique opportunity to test the details of Neptune's migration. Smooth migration should result in a measurable difference between the 3:2 and 2:1 with low inclination 2:1s having a red, binary population mirroring that of the CC itself while the 3:2 will be less contaminated. Alternative models with rapid migration would generate a more homogeneous result.

  5. Results from Binary Black Hole Simulations in Astrophysics Applications

    Science.gov (United States)

    Baker, John G.

    2007-01-01

    Present and planned gravitational wave observatories are opening a new astronomical window to the sky. A key source of gravitational waves is the merger of two black holes. The Laser Interferometer Space Antenna (LISA), in particular, is expected to observe these events with signal-to-noise ratio's in the thousands. To fully reap the scientific benefits of these observations requires a detailed understanding, based on numerical simulations, of the predictions of General Relativity for the waveform signals. New techniques for simulating binary black hole mergers, introduced two years ago, have led to dramatic advances in applied numerical simulation work. Over the last two years, numerical relativity researchers have made tremendous strides in understanding the late stages of binary black hole mergers. Simulations have been applied to test much of the basic physics of binary black hole interactions, showing robust results for merger waveform predictions, and illuminating such phenomena as spin-precession. Calculations have shown that merging systems can be kicked at up to 2500 km/s by the thrust from asymmetric emission. Recently, long lasting simulations of ten or more orbits allow tests of post-Newtonian (PN) approximation results for radiation from the last orbits of the binary's inspiral. Already, analytic waveform models based PN techniques with incorporated information from numerical simulations may be adequate for observations with current ground based observatories. As new advances in simulations continue to rapidly improve our theoretical understanding of the systems, it seems certain that high-precision predictions will be available in time for LISA and other advanced ground-based instruments. Future gravitational wave observatories are expected to make precision.

  6. SPECKLE INTERFEROMETRY AT SOAR IN 2010 AND 2011: MEASURES, ORBITS, AND RECTILINEAR FITS

    Energy Technology Data Exchange (ETDEWEB)

    Hartkopf, William I.; Mason, Brian D. [U.S. Naval Observatory, 3450 Massachusetts Ave., Washington, DC (United States); Tokovinin, Andrei, E-mail: wih@usno.navy.mil, E-mail: bdm@usno.navy.mil, E-mail: atokovinin@ctio.noao.edu [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile)

    2012-02-15

    We report on the results of speckle observations at the 4.1 m SOAR telescope in 2010 and 2011. A total of 639 objects were observed. We give 562 measurements of 418 resolved binaries, including 21 pairs resolved for the first time, and upper detection limits for 221 unresolved stars. New orbital elements have been determined for 42 physical pairs, of which 22 are first-time calculations; the rest are corrections, sometimes substantial. Linear elements are calculated for nine apparently optical doubles. We comment on new pairs, new orbital solutions, and other remarkable objects.

  7. Tides in asynchronous binary systems

    OpenAIRE

    Toledano, Oswaldo; Moreno, Edmundo; Koenigsberger, Gloria; Detmers, R.; Langer, Norbert

    2006-01-01

    Stellar oscillations are excited in non-synchronously rotating stars in binary systems due to the tidal forces. Tangential components of the tides can drive a shear flow which behaves as a differentially forced rotating structure in a stratified outer medium. In this paper we show that our single-layer approximation for the calculation of the forced oscillations yields results that are consistent with the predictions for the synchronization timescales in circular orbits. In addition, calibrat...

  8. Tidal capture formation of Low Mass X-Ray Binaries from wide binaries in the field

    CERN Document Server

    Michaely, Erez

    2015-01-01

    We present a potentially efficient dynamical formation scenario for Low Mass X-ray Binaries (LMXBs) in the field, focusing on black-hole (BH) LMXBs. In this formation channel LMXBs are formed from wide binaries $(>1000$ AU) with a BH component and a stellar companion. The wide binary is perturbed by fly-by's of field stars and its orbit random-walks and changes over time. This diffusion process can drive the binary into a sufficiently eccentric orbit such that the binary components tidally interact at peri-center and the binary evolves to become a short period binary, which eventually evolves into an LMXB. The formation rate of LMXBs through this channel mostly depends on the number of such BH wide binaries progenitors, which in turn depends on the velocity kicks imparted to BHs (or NSs) at birth. We consider several models for the formation and survival of such wide binaries, and calculate the LMXB formation rates for each model. We find that models where BHs form through direct collapse with no/little natal...

  9. The Circulation Pattern in Simulated Contact Binaries

    Science.gov (United States)

    Motl, Patrick M.; Frank, J.; Tohline, J. E.

    2006-06-01

    We present a three-dimensional hydrodynamical simulation of an initially symmetric (equal mass) binary where both components are marginally in contact. The simulation evolves the binary through approximately 150 orbital periods and within the first 20 orbits, a global velocity field is established that carries material between both components. In the equatorial plane, the flow is along a figure eight pattern with streams of material sliding past one another in the neighborhood of the inner Lagrange point. For our chosen equation of state, mass transfer is ultimately unstable in this binary though the growth time is long compared to the orbital period. We are therefore able to observe that the circulation pattern, once established, is quite close to steady state. We explore the role that similar steady state flows may play in real contact systems.

  10. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    International Nuclear Information System (INIS)

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 105-106 years.

  11. Eccentricity distribution of wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+-0.02 and the eccentricity distribution can be modeled as f(e) ~= 1.2 e + 0.4. However, wide binaries containing inner subsystems, i.e. triple or higher-order multiples, have significantly smaller eccentricities with the average e = 0.52+-0.05 and the peak at e ~ 0.5. We find that the catalog of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentr...

  12. Planet Scattering Around Binaries: Ejections, Not Collisions

    OpenAIRE

    Smullen, Rachel A.; Kratter, Kaitlin M.; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in...

  13. Milankovitch Cycles of Terrestrial Planets in Binary Star Systems

    Science.gov (United States)

    Forgan, Duncan

    2016-08-01

    The habitability of planets in binary star systems depends not only on the radiation environment created by the two stars, but also on the perturbations to planetary orbits and rotation produced by the gravitational field of the binary and neighbouring planets. Habitable planets in binaries may therefore experience significant perturbations in orbit and spin. The direct effects of orbital resonances and secular evolution on the climate of binary planets remain largely unconsidered. We present latitudinal energy balance modelling of exoplanet climates with direct coupling to an N Body integrator and an obliquity evolution model. This allows us to simultaneously investigate the thermal and dynamical evolution of planets orbiting binary stars, and discover gravito-climatic oscillations on dynamical and secular timescales. We investigate the Kepler-47 and Alpha Centauri systems as archetypes of P and S type binary systems respectively. In the first case, Earthlike planets would experience rapid Milankovitch cycles (of order 1000 years) in eccentricity, obliquity and precession, inducing temperature oscillations of similar periods (modulated by other planets in the system). These secular temperature variations have amplitudes similar to those induced on the much shorter timescale of the binary period. In the Alpha Centauri system, the influence of the secondary produces eccentricity variations on 15,000 year timescales. This produces climate oscillations of similar strength to the variation on the orbital timescale of the binary. Phase drifts between eccentricity and obliquity oscillations creates further cycles that are of order 100,000 years in duration, which are further modulated by neighbouring planets.

  14. Lyapunov timescales and black hole binaries

    International Nuclear Information System (INIS)

    Black hole binaries support unstable orbits at very close separations. In the simplest case of geodesics around a Schwarzschild black hole the orbits, though unstable, are regular. Under perturbation the unstable orbits can become the locus of chaos. All unstable orbits, whether regular or chaotic, can be quantified by their Lyapunov exponents. The exponents are observationally relevant since the phase of gravitational waves can decohere in a Lyapunov time. If the timescale for dissipation due to gravitational waves is shorter than the Lyapunov time, chaos will be damped and essentially unobservable. We find that the two timescales can be comparable. We emphasize that the Lyapunov exponents must only be used cautiously for several reasons: they are relative and depend on the coordinate system used, they vary from orbit to orbit, and finally they can be deceptively diluted by transient behaviour for orbits which pass in and out of unstable regions

  15. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    International Nuclear Information System (INIS)

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results

  16. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  17. BINARY ASTEROID ENCOUNTERS WITH TERRESTRIAL PLANETS: TIMESCALES AND EFFECTS

    International Nuclear Information System (INIS)

    Many asteroids that make close encounters with terrestrial planets are in a binary configuration. Here, we calculate the relevant encounter timescales and investigate the effects of encounters on a binary's mutual orbit. We use a combination of analytical and numerical approaches with a wide range of initial conditions. Our test cases include generic binaries with close, moderate, and wide separations, as well as seven well-characterized near-Earth binaries. We find that close approaches (<10 Earth radii) occur for almost all binaries on 1-10 million year timescales. At such distances, our results suggest substantial modifications to a binary's semimajor axis, eccentricity, and inclination, which we quantify. Encounters within 30 Earth radii typically occur on sub-million year timescales and significantly affect the wider binaries. Important processes in the lives of near-Earth binaries, such as tidal and radiative evolution, can be altered or stopped by planetary encounters.

  18. An Extremely Fast Halo Hot Subdwarf Star in a Wide Binary System

    Science.gov (United States)

    Németh, Péter; Ziegerer, Eva; Irrgang, Andreas; Geier, Stephan; Fürst, Felix; Kupfer, Thomas; Heber, Ulrich

    2016-04-01

    New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 (V = 17.92 mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities are consistent with the same distance, confirming the physical nature of the binary, which is the first double-lined hyper-velocity candidate. Our spectral decomposition of the Keck/ESI spectrum provided an sdB+K3V pair, analogous to many long-period subdwarf binaries observed in the Galactic disk. We found the subdwarf atmospheric parameters: {T}{{eff}}=30\\600+/- 500 K, {log}g=5.57+/- 0.06 cm s-2, and He abundance {log}(n{{He}}/n{{H}})=-3.0+/- 0.2. Oxygen is the most abundant metal in the hot subdwarf atmosphere, and Mg and Na lines are the most prominent spectral features of the cool companion, consistent with a metallicity of [{{Fe}}/{{H}}]=-1.3. The non-detection of radial velocity variations suggest the orbital period to be a few hundred days, in agreement with similar binaries observed in the disk. Using the SDSS-III flux calibrated spectrum we measured the distance to the system d=5.5+/- 0.5 {{kpc}}, which is consistent with ultraviolet, optical, and infrared photometric constraints derived from binary spectral energy distributions. Our kinematic study shows that the Galactic rest-frame velocity of the system is so high that an unbound orbit cannot be ruled out. On the other hand, a bound orbit requires a massive dark matter halo. We conclude that the binary either formed in the halo or was accreted from the tidal debris of a dwarf galaxy by the Milky Way.

  19. An Extremely Fast Halo Hot Subdwarf Star in a Wide Binary System

    Science.gov (United States)

    Németh, Péter; Ziegerer, Eva; Irrgang, Andreas; Geier, Stephan; Fürst, Felix; Kupfer, Thomas; Heber, Ulrich

    2016-04-01

    New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 (V = 17.92 mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities are consistent with the same distance, confirming the physical nature of the binary, which is the first double-lined hyper-velocity candidate. Our spectral decomposition of the Keck/ESI spectrum provided an sdB+K3V pair, analogous to many long-period subdwarf binaries observed in the Galactic disk. We found the subdwarf atmospheric parameters: {T}{{eff}}=30\\600+/- 500 K, {log}g=5.57+/- 0.06 cm s‑2, and He abundance {log}(n{{He}}/n{{H}})=-3.0+/- 0.2. Oxygen is the most abundant metal in the hot subdwarf atmosphere, and Mg and Na lines are the most prominent spectral features of the cool companion, consistent with a metallicity of [{{Fe}}/{{H}}]=-1.3. The non-detection of radial velocity variations suggest the orbital period to be a few hundred days, in agreement with similar binaries observed in the disk. Using the SDSS-III flux calibrated spectrum we measured the distance to the system d=5.5+/- 0.5 {{kpc}}, which is consistent with ultraviolet, optical, and infrared photometric constraints derived from binary spectral energy distributions. Our kinematic study shows that the Galactic rest-frame velocity of the system is so high that an unbound orbit cannot be ruled out. On the other hand, a bound orbit requires a massive dark matter halo. We conclude that the binary either formed in the halo or was accreted from the tidal debris of a dwarf galaxy by the Milky Way.

  20. Classification of Stellar Orbits in Axisymmetric Galaxies

    Science.gov (United States)

    Li, Baile; Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-01

    It is known that two supermassive black holes (SMBHs) cannot merge in a spherical galaxy within a Hubble time; an emerging picture is that galaxy geometry, rotation, and large potential perturbations may usher the SMBH binary through the critical three-body scattering phase and ultimately drive the SMBH to coalesce. We explore the orbital content within an N-body model of a mildly flattened, non-rotating, SMBH-embedded elliptical galaxy. When used as the foundation for a study on the SMBH binary coalescence, the black holes bypassed the binary stalling often seen within spherical galaxies and merged on gigayear timescales. Using both frequency-mapping and angular momentum criteria, we identify a wealth of resonant orbits in the axisymmetric model, including saucers, that are absent from an otherwise identical spherical system and that can potentially interact with the binary. We quantified the set of orbits that could be scattered by the SMBH binary, and found that the axisymmetric model contained nearly six times the number of these potential loss cone orbits compared to our equivalent spherical model. In this flattened model, the mass of these orbits is more than three times that of the SMBH, which is consistent with what the SMBH binary needs to scatter to transition into the gravitational wave regime.

  1. Identifying Decaying Supermassive Black Hole Binaries from their Variable Electromagnetic Emission

    CERN Document Server

    Haiman, Zoltán; Menou, Kristen; Lippai, Zoltán; Frei, Zsolt

    2008-01-01

    Supermassive black hole binaries (SMBHBs) with masses in the range 10^4-10^7 M_sun/(1+z), produced in galaxy mergers, are thought to complete their coalescence due to the emission of gravitational waves (GWs). The anticipated detection of the GWs by the LISA will constitute a milestone for fundamental physics and astrophysics. While the GW signatures themselves will provide a treasure trove of information, if the source can be securely identified in electromagnetic (EM) bands, this would open up entirely new scientific opportunities, to probe fundamental physics, astrophysics, and cosmology. We discuss several ideas, involving wide-field telescopes, that may be useful in locating electromagnetic counterparts to SMBHBs detected by LISA. In particular, the binary may produce a variable electromagnetic flux, such as a roughly periodic signal due to the orbital motion prior to coalescence, or a prompt transient signal caused by shocks in the circumbinary disk when the SMBHB recoils and "shakes" the disk. We discu...

  2. Binaries and distances

    Science.gov (United States)

    Pourbaix, D.; Arenou, F.; Halbwachs, J.-L.; Siopis, C.

    2013-02-01

    Gaia's five-year observation baseline might naively lead to the expectation that it will be possible to fit the parallax of any sufficiently nearby object with the default five-parameter model (position at a reference epoch, parallax and proper motion). However, simulated Gaia observations of a `model Universe' composed of nearly 107 objects, 50% of which turn out to be multiple stars, show that the single-star hypothesis can severely affect parallax estimation and that more sophisticated models must be adopted. In principle, screening these spurious single-star solutions is rather straightforward, for example by evaluating the quality of the fits. However, the simulated Gaia observations also reveal that some seemingly acceptable single-star solutions can nonetheless lead to erroneous distances. These solutions turn out to be binaries with an orbital period close to one year. Without auxiliary (e.g., spectroscopic) data, they will remain unnoticed.

  3. Spin-Spin Coupling in Asteroidal Binaries

    Science.gov (United States)

    Batygin, Konstantin; Morbidelli, Alessandro

    2015-11-01

    Gravitationally bound binaries constitute a substantial fraction of the small body population of the solar system, and characterization of their rotational states is instrumental to understanding their formation and dynamical evolution. Unlike planets, numerous small bodies can maintain a perpetual aspheroidal shape, giving rise to a richer array of non-trivial gravitational dynamics. In this work, we explore the rotational evolution of triaxial satellites that orbit permanently deformed central objects, with specific emphasis on quadrupole-quadrupole interactions. Our analysis shows that in addition to conventional spin-orbit resonances, both prograde and retrograde spin-spin resonances naturally arise for closely orbiting, highly deformed bodies. Application of our results to the illustrative examples of (87) Sylvia and (216) Kleopatra multi-asteroid systems implies capture probabilities slightly below ~10% for leading-order spin-spin resonances. Cumulatively, our results suggest that spin-spin coupling may be consequential for highly elongated, tightly orbiting binary objects.

  4. Orbital maneuvers and space rendezvous

    Science.gov (United States)

    Butikov, Eugene I.

    2015-12-01

    Several possibilities of launching a space vehicle from the orbital station are considered and compared. Orbital maneuvers discussed in the paper can be useful in designing a trajectory for a specific space mission. The relative motion of orbiting bodies is investigated on examples of spacecraft rendezvous with the space station that stays in a circular orbit around the Earth. An elementary approach is illustrated by an accompanying simulation computer program and supported by a mathematical treatment based on fundamental laws of physics and conservation laws. Material is appropriate for engineers and other personnel involved in space exploration, undergraduate and graduate students studying classical physics and orbital mechanics.

  5. Optical Identification of Close White Dwarf Binaries in the LISA Era

    CERN Document Server

    Cooray, A R; Seto, N; Cooray, Asantha; Farmer, Alison J.; Seto, Naoki

    2004-01-01

    The Laser Interferometer Space Antenna (LISA) is expected to detect close white dwarf binaries (CWDBs) through their gravitational radiation. Around 3000 binaries will be spectrally resolved at frequencies > 3 mHz, and their positions on the sky will be determined to an accuracy ranging from a few tens of arcminutes to a degree or more. Due to the small binary separation, the optical light curves of >~ 30% of these CWDBs are expected to show eclipses, giving a unique signature for identification in follow-up studies of the LISA error boxes. While the precise optical location improves binary parameter determination with LISA data, the optical light curve captures additional physics of the binary, including the individual sizes of the stars in terms of the orbital separation. To optically identify a substantial fraction of CWDBs and thus localize them very accurately, a rapid monitoring campaign is required, capable of imaging a square degree or more in a reasonable time, at intervals of 10--100 seconds, to mag...

  6. Gravitational Radiation from Post-Newtonian Sources and Inspiralling Compact Binaries

    Directory of Open Access Journals (Sweden)

    Blanchet Luc

    2006-06-01

    Full Text Available The article reviews the current status of a theoretical approach to the problem of the emission of gravitational waves by isolated systems in the context of general relativity. Part A of the article deals with general post-Newtonian sources. The exterior field of the source is investigated by means of a combination of analytic post-Minkowskian and multipolar approximations. The physical observables in the far-zone of the source are described by a specific set of radiative multipole moments. By matching the exterior solution to the metric of the post-Newtonian source in the near-zone we obtain the explicit expressions of the source multipole moments. The relationships between the radiative and source moments involve many non-linear multipole interactions, among them those associated with the tails (and tails-of-tails of gravitational waves. Part B of the article is devoted to the application to compact binary systems. We present the equations of binary motion, and the associated Lagrangian and Hamiltonian, at the third post-Newtonian (3PN order beyond the Newtonian acceleration. The gravitational-wave energy flux, taking consistently into account the relativistic corrections in the binary moments as well as the various tail effects, is derived through 3.5PN order with respect to the quadrupole formalism. The binary's orbital phase, whose prior knowledge is crucial for searching and analyzing the signals from inspiralling compact binaries, is deduced from an energy balance argument.

  7. Tidal effects and periastron events in binary stars

    OpenAIRE

    Koenigsberger, Gloria; Moreno, Edmundo

    2009-01-01

    Binary stars in eccentric orbits are frequently reported to present increasing levels of activity around periastron passage. In this paper we present results of a calculation from first principles of the velocity field on the surface of a star that is perturbed by a binary companion. This allows us to follow the orbital phase-dependence of the amount of kinetic energy that may be dissipated through the viscous shear, dot-E, driven by tidal interactions. For stars with relatively small stellar...

  8. Magnetic Interaction in Ultra-compact Binary Systems

    CERN Document Server

    Wu, Kinwah

    2009-01-01

    This article reviews the current works on ultra-compact double-degenerate binaries in the presence of magnetic interaction, in particular, unipolar induction. The orbital dynamics and evolution of compact white-dwarf pairs are discussed in detail. Models and predictions of electron cyclotron masers from unipolar-inductor compact binaries and unipolar-inductor white-dwarf planetary systems are presented. Einstein-Laub effects in compact binaries are briefly discussed.

  9. Magnetic interaction in ultra-compact binary systems

    Institute of Scientific and Technical Information of China (English)

    Kinwah WU

    2009-01-01

    This article reviews the current works on ultra-compact double-degenerate binaries in the presence of magnetic interaction, in particular, unipolar induction. The orbital dynamics and evolution of compact white-dwarf pairs are discussed in detail. Models and predictions of electron cyclotron masers from unipolar-inductor compact binaries and unipolar-inductor white-dwarf planetary systems are presented. Einstein-Laub effects in compact binaries are briefly discussed.

  10. Apsidal motion in the massive binary HD152218

    CERN Document Server

    Rauw, G; Noels, A; Mahy, L; Schmitt, J H M M; Godart, M; Dupret, M -A; Gosset, E

    2016-01-01

    Massive binary systems are important laboratories in which to probe the properties of massive stars and stellar physics in general. In this context, we analysed optical spectroscopy and photometry of the eccentric short-period early-type binary HD 152218 in the young open cluster NGC 6231. We reconstructed the spectra of the individual stars using a separating code. The individual spectra were then compared with synthetic spectra obtained with the CMFGEN model atmosphere code. We furthermore analysed the light curve of the binary and used it to constrain the orbital inclination and to derive absolute masses of 19.8 +/- 1.5 and 15.0 +/- 1.1 solar masses. Combining radial velocity measurements from over 60 years, we show that the system displays apsidal motion at a rate of (2.04^{+.23}_{-.24}) degree/year. Solving the Clairaut-Radau equation, we used stellar evolution models, obtained with the CLES code, to compute the internal structure constants and to evaluate the theoretically predicted rate of apsidal moti...

  11. Observations of Binary and Millisecond Pulsars at Xinjiang Astronomical Observatory

    Indian Academy of Sciences (India)

    Jingbo Wang; Na Wang; Jianping Yuan; Zhiyong Liu

    2014-09-01

    We present the first results of radio timing observations of binary and millisecond pulsars in China. We have timed four binary pulsars for 9 years, using Nanshan 25-m radio telescope. The long time span has enabled us to determine their rotation and orbital parameters.

  12. A Detached Eclipsing Binary near the Turnoff of the Open Cluster NGC 6819 and Determining Age Using Kepler

    DEFF Research Database (Denmark)

    Brewer, Lauren; Sandquist, E. L.; Mathieu, R. D.;

    2013-01-01

    Measurements of the mass and radius of detached eclipsing binaries (DEB) can be used to accurately determine the ages of clusters if an eclipsing star is evolved enough and sits near the cluster turnoff on the color-magnitude diagram (CMD). Multiple DEBs in a cluster can constrain the age even more...... tightly, and can also lead to inferences about chemical composition (such as helium abundance). As part of our study of the old 2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present results for the DEB Auner 665 (WOCS 24009) with a short period of 3.6 days. We make use of photometric observations...... star is physically orbiting the eclipsing binary based on radial velocities and eclipse timing variations. The stars that make up the detached eclipsing binary are almost identical in temperature, with eclipses that are only clearly distinguishable using Kepler photometry. A new astrometric study of...

  13. Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cygni

    Czech Academy of Sciences Publication Activity Database

    Harmanec, P.; Holmgren, D. E.; Wolf, M.; Bozic, H.; Guinan, E. F.; Kang, Y. W.; Mayer, P.; McCook, G.; Nemravová, J.; Yang, S.; Šlechta, Miroslav; Ruzdjak, D.; Sudar, D.; Svoboda, P.

    2014-01-01

    Roč. 563, March (2014), A120/1-A120/12. ISSN 0004-6361 R&D Projects: GA ČR GA205/06/0584 Institutional research plan: CEZ:AV0Z10030501 Keywords : binaries: spectroscopic * stars: fundamental parameters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  14. Multiple Bifurcations in the Periodic Orbit around Eros

    CERN Document Server

    Ni, Yanshuo; Baoyin, Hexi

    2016-01-01

    We investigate the multiple bifurcations in periodic orbit families in the potential field of a highly irregular-shaped celestial body. Topological cases of periodic orbits and four kinds of basic bifurcations in periodic orbit families are studied. Multiple bifurcations in periodic orbit families consist of four kinds of basic bifurcations. We found both binary period-doubling bifurcations and binary tangent bifurcations in periodic orbit families around asteroid 433 Eros. The periodic orbit family with binary period-doubling bifurcations is nearly circular, with almost zero inclination, and is reversed relative to the body of the asteroid 433 Eros. This implies that there are two stable regions separated by one unstable region for the motion around this asteroid. In addition, we found triple bifurcations which consist of two real saddle bifurcations and one period-doubling bifurcation. A periodic orbit family generated from an equilibrium point of asteroid 433 Eros has five bifurcations, which are one real ...

  15. Low autocorrelation binary sequences

    Science.gov (United States)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  16. Orbital pseudotumor

    Science.gov (United States)

    ... Names Idiopathic orbital inflammatory syndrome (IOIS) Images Skull anatomy References Goodlick TA, Kay MD, Glaser JS, Tse DT, Chang WJ. Orbital disease and neuro-ophthalmology. In: Tasman W, Jaeger EA, eds. Duane’s ...

  17. NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

    International Nuclear Information System (INIS)

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' ∼> 10-100 M⊕ at orbital periods P ≈ 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P ∼3[P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the standard three-wave parametric instability. These are local instabilities viewed through the lens of global analysis; the coherent global growth rate follows local rates in the regions where the shear is strongest. In solar-type stars, the dynamical tide is unstable to this collective version of the parametric instability for even sub-Jupiter companion masses with P ∼< a month. (4) Independent of the parametric instability, the dynamical and equilibrium tides excite a wide range of stellar p-modes and g-modes by nonlinear inhomogeneous forcing

  18. Nonlinear Tides in Close Binary Systems

    Science.gov (United States)

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-06-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' >~ 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static "equilibrium" tidal distortion is, however, stable to parametric resonance except for solar binaries with P companion masses larger than a few Jupiter masses, the dynamical tide causes short length scale waves to grow so rapidly that they must be treated as traveling waves, rather than standing waves. (3) We show that the global three-wave treatment of parametric instability typically used in the astrophysics literature does not yield the fastest-growing daughter modes or instability threshold in many cases. We find a form of parametric instability in which a single parent wave excites a very large number of daughter waves (N ≈ 103[P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the standard three

  19. CFD Simulations of Binary Nucleation

    Czech Academy of Sciences Publication Activity Database

    Herrmann, E.; Brus, David; Hyvärinen, A-P.; Kulmala, M.

    Helsinki : -, 2010, P3U16. ISBN N. [International Aerosol Conference IAC 2010. Helsinki (FI), 29.08.2010-03.09.2010] Grant ostatní: FCR(FI) 1118615 Institutional research plan: CEZ:AV0Z40720504 Keywords : nucleation * binary * parameterization Subject RIV: CF - Physical ; Theoretical Chemistry www.iac2010.fi

  20. Binary pulsars as dark-matter probes

    CERN Document Server

    Pani, Paolo

    2015-01-01

    During the motion of a binary pulsar around the galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a characteristic seasonal modulation of the orbit and causes a secular change of the orbital period whose magnitude can be well within the astonishing precision of various binary-pulsar observations. Our analysis is valid for binary systems with orbital period longer than a day. By comparing this effect with pulsar-timing measurements, it is possible to derive model-independent upper bounds on the dark-matter density at different distances $D$ from the galactic center. For example, the precision timing of J1713+0747 imposes $\\rho_{\\rm DM}\\lesssim 10^5\\,{\\rm GeV/cm}^3$ at $D\\approx7\\,{\\rm kpc}$. The detection of a binary pulsar at $D\\lesssim 10\\,{\\rm pc}$ could provide stringent constraints on dark-matter halo profiles and on growth models of the central black hole. The Square Kil...

  1. Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

    Science.gov (United States)

    Fryer, Chris L; Oliveira, F G; Rueda, J A; Ruffini, R

    2015-12-01

    Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52}  erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs. PMID:26684106

  2. Analysing weak orbital signals in Gaia data

    Science.gov (United States)

    Lucy, L. B.

    2014-11-01

    Anomalous orbits are found when minimum-χ2 estimation is applied to synthetic Gaia data for orbits with astrometric signatures comparable to the single-scan measurement error (Pourbaix 2002, A&A, 385, 686). These orbits are nearly parabolic, edge-on, and their major axes align with the line-of-sight to the observer. Such orbits violate the Copernican principle (CPr) and as such could be rejected. However, the preferred alternative is to develop a statistical technique that incorporates the CPr as a fundamental postulate. This can be achieved in a Bayesian context by defining a Copernican prior. Pourbaix's anomalous orbits then no longer arise. Instead, the selected orbits have a somewat higher χ2 but do not violate the CPr. The problem of detecting a weak additional orbit in an astrometric binary with a well-determined orbit is also treated.

  3. A Galactic Binary Detection Pipeline

    Science.gov (United States)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  4. Terrain physical properties derived from orbital data and the first 360 sols of Mars Science Laboratory Curiosity rover observations in Gale Crater

    Science.gov (United States)

    Arvidson, R. E.; Bellutta, P.; Calef, F.; Fraeman, A. A.; Garvin, J. B.; Gasnault, O.; Grant, J. A.; Grotzinger, J. P.; Hamilton, V. E.; Heverly, M.; Iagnemma, K. A.; Johnson, J. R.; Lanza, N.; Le Mouélic, S.; Mangold, N.; Ming, D. W.; Mehta, M.; Morris, R. V.; Newsom, H. E.; Rennó, N.; Rubin, D.; Schieber, J.; Sletten, R.; Stein, N. T.; Thuillier, F.; Vasavada, A. R.; Vizcaino, J.; Wiens, R. C.

    2014-06-01

    Physical properties of terrains encountered by the Curiosity rover during the first 360 sols of operations have been inferred from analysis of the scour zones produced by Sky Crane Landing System engine plumes, wheel touch down dynamics, pits produced by Chemical Camera (ChemCam) laser shots, rover wheel traverses over rocks, the extent of sinkage into soils, and the magnitude and sign of rover-based slippage during drives. Results have been integrated with morphologic, mineralogic, and thermophysical properties derived from orbital data, and Curiosity-based measurements, to understand the nature and origin of physical properties of traversed terrains. The hummocky plains (HP) landing site and traverse locations consist of moderately to well-consolidated bedrock of alluvial origin variably covered by slightly cohesive, hard-packed basaltic sand and dust, with both embedded and surface-strewn rock clasts. Rock clasts have been added through local bedrock weathering and impact ejecta emplacement and form a pavement-like surface in which only small clasts (resistance countering driven-wheel thrust has been minimal and that rover slippage while traversing across horizontal surfaces or going uphill, and skid going downhill, have been dominated by terrain tilts and wheel-surface material shear modulus values.

  5. Event Rates for Binary Inspiral

    CERN Document Server

    Kalogera, V

    2001-01-01

    Double compact objects (neutron stars and black holes) found in binaries with small orbital separations are known to spiral in and are expected to coalesce eventually because of the emission of gravitational waves. Such inspiral and merger events are thought to be primary sources for ground based gravitational-wave interferometric detectors (such as LIGO). Here, we present a brief review of estimates of coalescence rates and we examine the origin and relative importance of uncertainties associated with the rate estimates. For the case of double neutron star systems, we compare the most recent rate estimates to upper limits derived in a number of different ways. We also discuss the implications of the formation of close binaries with two non-recycled pulsars.

  6. Physical properties, starspot activity, orbital obliquity, and transmission spectrum of the Qatar-2 planetary system from multi-colour photometr

    CERN Document Server

    Mancini, L; Ciceri, S; Tregloan-Reed, J; Crossfield, I; Nikolov, N; Bruni, I; Zambelli, R; Henning, Th

    2014-01-01

    We present seventeen high-precision light curves of five transits of the planet Qatar-2b, obtained from four defocussed 2m-class telescopes. Three of the transits were observed simultaneously in the SDSS griz passbands using the seven-beam GROND imager on the MPG/ESO 2.2-m telescope. A fourth was observed simultaneously in Gunn grz using the CAHA 2.2-m telescope with BUSCA, and in r using the Cassini 1.52-m telescope. Every light curve shows small anomalies due to the passage of the planetary shadow over a cool spot on the surface of the host star. We fit the light curves with the prism+gemc model to obtain the photometric parameters of the system and the position, size and contrast of each spot. We use these photometric parameters and published spectroscopic measurements to obtain the physical properties of the system to high precision, finding a larger radius and lower density for both star and planet than previously thought. By tracking the change in position of one starspot between two transit observation...

  7. On the point mass approximation to calculate the gravitational wave signal from white dwarf binaries

    OpenAIRE

    Broek, D. van den; Nelemans, G. A.; Dan, M; Rosswog, S.

    2012-01-01

    Double white dwarf binaries in the Galaxy dominate the gravitational wave sky and would be detectable for an instrument such as LISA. Most studies have calculated the expected gravitational wave signal under the assumption that the binary white dwarf system can be represented by two point masses in orbit. We discuss the accuracy of this approximation for real astrophysical systems. For non-relativistic binaries in circular orbit the gravitational wave signal can easily be calculated. We show ...

  8. The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

    Energy Technology Data Exchange (ETDEWEB)

    Samsing, Johan [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); MacLeod, Morgan; Ramirez-Ruiz, Enrico [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2014-03-20

    The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a {sup 2/7}. Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

  9. Dynamical Mass Ejection from Binary Neutron Star Mergers

    Science.gov (United States)

    Radice, David; Galeazzi, Filippo; Lippuner, Jonas; Roberts, Luke F.; Ott, Christian D.; Rezzolla, Luciano

    2016-05-01

    We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation of state. We study the dynamical mass ejection from both quasi-circular and dynamical-capture eccentric mergers. We systematically vary the level of our treatment of the microphysics to isolate the effects of neutrino cooling and heating and we compute the nucleosynthetic yields of the ejecta. We find that eccentric binaries can eject significantly more material than quasi-circular binaries and generate bright infrared and radio emission. In all our simulations the outflow is composed of a combination of tidally- and shock-driven ejecta, mostly distributed over a broad ˜60° angle from the orbital plane, and, to a lesser extent, by thermally driven winds at high latitudes. Ejecta from eccentric mergers are typically more neutron rich than those of quasi-circular mergers. We find neutrino cooling and heating to affect, quantitatively and qualitatively, composition, morphology, and total mass of the outflows. This is also reflected in the infrared and radio signatures of the binary. The final nucleosynthetic yields of the ejecta are robust and insensitive to input physics or merger type in the regions of the second and third r-process peaks. The yields for elements on the first peak vary between our simulations, but none of our models is able to explain the Solar abundances of first-peak elements without invoking additional first-peak contributions from either neutrino and viscously-driven winds operating on longer timescales after the mergers, or from core-collapse supernovae.

  10. Dynamical mass ejection from binary neutron star mergers

    Science.gov (United States)

    Radice, David; Galeazzi, Filippo; Lippuner, Jonas; Roberts, Luke F.; Ott, Christian D.; Rezzolla, Luciano

    2016-08-01

    We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation of state. We study the dynamical mass ejection from both quasi-circular and dynamical-capture eccentric mergers. We systematically vary the level of our treatment of the microphysics to isolate the effects of neutrino cooling and heating and we compute the nucleosynthetic yields of the ejecta. We find that eccentric binaries can eject significantly more material than quasi-circular binaries and generate bright infrared and radio emission. In all our simulations the outflow is composed of a combination of tidally- and shock-driven ejecta, mostly distributed over a broad ˜60° angle from the orbital plane, and, to a lesser extent, by thermally driven winds at high latitudes. Ejecta from eccentric mergers are typically more neutron rich than those of quasi-circular mergers. We find neutrino cooling and heating to affect, quantitatively and qualitatively, composition, morphology, and total mass of the outflows. This is also reflected in the infrared and radio signatures of the binary. The final nucleosynthetic yields of the ejecta are robust and insensitive to input physics or merger type in the regions of the second and third r-process peaks. The yields for elements on the first peak vary between our simulations, but none of our models is able to explain the Solar abundances of first-peak elements without invoking additional first-peak contributions from either neutrino and viscously-driven winds operating on longer time-scales after the mergers, or from core-collapse supernovae.

  11. Structure and nature of gamma-ray binaries by means of VLBI observations

    OpenAIRE

    Moldón Vara, Francisco Javier

    2012-01-01

    Gamma-ray binaries are extreme systems that produce non-thermal emission from radio to very-high-energy (above TeV) gamma rays, with the energy output in the spectral energy distribution (SED) dominated by the MeV–GeV photons. Their broadband emission is usually modulated by the orbital cycle of the system, which suggests that the physical conditions are also periodic and reproducible. The diversity of systems, together with the reproducibility of the conditions within each system, makes gamm...

  12. Orbits and Interiors of Planets

    Science.gov (United States)

    Batygin, Konstantin

    2012-05-01

    independent constraints for the solar system's birth environment. Next, we addressed a significant drawback of the original Nice model, namely its inability to create the physically unique, cold classical population of the Kuiper Belt. Specifically, we showed that a locally-formed cold belt can survive the transient instability, and its relatively calm dynamical structure can be reproduced. The last four chapters of this thesis address various aspects and consequences of dynamical relaxation of planetary orbits through dissipative effects as well as the formation of planets in binary stellar systems. Using octopole-order secular perturbation theory, we demonstrated that in multi-planet systems, tidal dissipation often drives orbits onto dynamical "fixed points," characterized by apsidal alignment and lack of periodic variations in eccentricities. We applied this formalism towards investigating the possibility that the large orbital eccentricity of the transiting Neptune-mass planet Gliese 436b is maintained in the face of tidal dissipation by a second planet in the system and computed a locus of possible orbits for the putative perturber. Following up along similar lines, we used various permutations of secular theory to show that when applied specifically to close-in low-mass planetary systems, various terms in the perturbation equations become separable, and the true masses of the planets can be solved for algebraically. In practice, this means that precise knowledge of the system's orbital state can resolve the sin( i) degeneracy inherent to non-transiting planets. Subsequently, we investigated the onset of chaotic motion in dissipative planetary systems. We worked in the context of classical secular perturbation theory, and showed that planetary systems approach chaos via the so-called period-doubling route. Furthermore, we demonstrated that chaotic strange attractors can exist in mildly damped systems, such as photo-evaporating nebulae that host multiple planets. Finally

  13. DESTRUCTION OF BINARY MINOR PLANETS DURING NEPTUNE SCATTERING

    International Nuclear Information System (INIS)

    The existence of extremely wide binaries in the low-inclination component of the Kuiper Belt provides a unique handle on the dynamical history of this population. Some popular frameworks of the formation of the Kuiper Belt suggest that planetesimals were moved there from lower semimajor axis orbits by scattering encounters with Neptune. We test the effects such events would have on binary systems and find that wide binaries are efficiently destroyed by the kinds of scattering events required to create the Kuiper Belt with this mechanism. This indicates that a binary-bearing component of the cold Kuiper Belt was emplaced through a gentler mechanism or was formed in situ.

  14. Black-Hole Binaries, Gravitational Waves, and Numerical Relativity

    Science.gov (United States)

    Kelly, Bernard J.; Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

    2010-01-01

    Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events ' releasing tremendous amounts of energy in the form of gravitational radiation ' and are key sources for both ground- and spacebased gravitational wave detectors. The black-hole merger dynamics and the resulting gravitational waveforms can only he calculated through numerical simulations of Einstein's equations of general relativity. For many years, numerical relativists attempting to model these mergers encountered a host of problems, causing their codes to crash after just a fraction of a binary orbit cnuld be simulated. Recently ' however, a series of dramatic advances in numerical relativity has ' for the first time, allowed stable / robust black hole merger simulations. We chronicle this remarkable progress in the rapidly maturing field of numerical relativity, and the new understanding of black-hole binary dynamics that is emerging. We also discuss important applications of these fundamental physics results to astrophysics, to gravitationalwave astronomy, and in other areas.

  15. Determining the Age of the Kepler Open Cluster NGC 6819 With a New Triple System and Other Eclipsing Binary Stars

    CERN Document Server

    Brewer, Lauren N; Mathieu, Robert D; Milliman, Katelyn; Geller, Aaron M; Jeffries, Mark W; Orosz, Jerome A; Brogaard, Karsten; Platais, Imants; Bruntt, Hans; Grundahl, Frank; Stello, Dennis; Frandsen, Soeren

    2016-01-01

    As part of our study of the old (~2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVRcIc) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC 5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M_B =1.090+/-0.010 Msun and M_C =1.075+/-0.013 Msun, and radii R_B =1.095+/-0.007 Rsun and R_C =1.057+/-0.008 Rsun. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M_A =1.251+/-0.057 Msun. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, which enables us to precisely decompose the light of the three stars and pl...

  16. Toward Complete Statistics of Massive Binary Stars: Penultimate Results from the Cygnus OB2 Radial Velocity Survey

    CERN Document Server

    Kobulnicky, Henry A; Lundquist, Michael J; Burke, Jamison; Chapman, James; Keller, Erica; Lester, Kathryn; Rolen, Emily K; Topel, Eric; Bhattacharjee, Anirban; Smullen, Rachel A; Alvarez, Carlos A Vargas; Runnoe, Jessie C; Dale, Daniel A; Brotherton, Michael M

    2014-01-01

    We analyze orbital solutions for 48 massive multiple-star systems in the Cygnus OB2 Association, 23 of which are newly presented here, to find that the observed distribution of orbital periods is approximately uniform in log P for P 45 d, even after correction for completeness, indicating either a lower binary fraction or a shift toward low-mass companions. A high degree of similarity (91% likelihood) between the Cyg OB2 period distribution and that of other surveys suggests that the binary properties at P<25 d are determined by local physics of disk/clump fragmentation and are relatively insensitive to environmental and evolutionary factors. Fully 30% of the unbiased parent sample is a binary with period P < 45 d. Completeness corrections imply a binary fraction near 55% for P < 5000 d. The observed distribution of mass ratios 0.2

  17. On the diversity and similarity of outbursts of symbiotic binaries and cataclysmic variables

    CERN Document Server

    Skopal, Augustin

    2015-01-01

    Outbursts in two classes of interacting binary systems, the symbiotic stars (SSs) and the cataclysmic variables (CVs), show a number of similarities in spite of very different orbital periods. Typical values for SSs are in the order of years, whereas for CVs they are of a few hours. Both systems undergo unpredictable outbursts, characterized by a brightening in the optical by 1 - 3 and 7 - 15 mag for SSs and CVs, respectively. By modelling the multiwavelength SED of selected examples from both groups of these interacting binaries, I determine their basic physical parameters at a given time of the outburst evolution. In this way I show that the principal difference between outbursts of these objects is their violence, whereas the ionization structure of their ejecta is basically very similar. This suggests that the mechanism of the mass ejection by the white dwarfs in these systems is also similar.

  18. Migration into a Companion's Trap: Disruption of Multiplanet Systems in Binaries

    CERN Document Server

    Touma, Jihad R

    2015-01-01

    Most exoplanetary systems in binary stars are of S--type, and consist of one or more planets orbiting a primary star with a wide binary stellar companion. Gravitational forcing of a single planet by a sufficiently inclined binary orbit can induce large amplitude oscillations of the planet's eccentricity and inclination through the Kozai-Lidov (KL) instability. KL cycling was invoked to explain: the large eccentricities of planetary orbits; the family of close--in hot Jupiters; and the retrograde planetary orbits in eccentric binary systems. However, several kinds of perturbations can quench the KL instability, by inducing fast periapse precessions which stabilize circular orbits of all inclinations: these could be a Jupiter--mass planet, a massive remnant disc or general relativistic precession. Indeed, mutual gravitational perturbations in multiplanet S--type systems can be strong enough to lend a certain dynamical rigidity to their orbital planes. Here we present a new and faster process that is driven by t...

  19. White-Light Flares on Close Binaries Observed with Kepler

    CERN Document Server

    Gao, Qing; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

    2016-01-01

    Based on Kepler data, we present the results of a search for white-light flares on 1049 close binaries. We identify 234 flare binaries, on which 6818 flares are detected. We compare the flare-binary fraction in different binary morphologies ("detachedness"). The result shows that the fractions in over-contact and ellipsoidal binaries are approximately 10-20 percent lower than those in detached and semi-detached systems. We calculate the binary flares activity level (AL) of all the flare binaries, and discuss its variations along the orbital period (P_orb) and rotation period (P_rot, calculated for only detached binaries). We find that AL increases with decreasing P_orb or P_rot up to the critical values at P_orb near 3 days or P_rot near 1.5 days, thereafter, the AL starts decreasing no matter how fast the stars rotate. We examine the flaring rate as a function of orbital phase in 2 eclipsing binaries on which a large number of flares are detected. It appears that there is no correlation between flaring rate ...

  20. High-Energy Emission at Shocks in Millisecond Pulsar Binaries

    Science.gov (United States)

    Kust Harding, Alice; Wadiasingh, Zorawar; Venter, Christo; Boettcher, Markus

    2016-04-01

    A large number of new Black Widow (BW) and Redback (RB) energetic millisecond pulsars have been discovered through radio searches of unidentified Fermi sources, increasing the known number of these systems from 4 to 28. We model the high-energy emission components from particles accelerated to several TeV in intrabinary shocks in BW and RB systems, and their predicted modulation at the binary orbital period. Synchrotron emission is expected at X-ray energies and such modulated emission has already been detected by Chandra and XMM. Inverse Compton emission from accelerated particles scattering the UV emission from the radiated companion star is expected in the Fermi and TeV bands. Detections or constraints on this emission will probe the unknown physics of pulsar winds.

  1. Simulating binary neutron stars: dynamics and gravitational waves

    OpenAIRE

    Anderson, Matthew; Hirschmann, Eric W.; Lehner, Luis; Liebling, Steven L.; Motl, Patrick M.; Neilsen, David; Palenzuela, Carlos; Tohline, Joel E.

    2007-01-01

    We model two mergers of orbiting binary neutron stars, the first forming a black hole and the second a differentially rotating neutron star. We extract gravitational waveforms in the wave zone. Comparisons to a post-Newtonian analysis allow us to compute the orbital kinematics, including trajectories and orbital eccentricities. We verify our code by evolving single stars and extracting radial perturbative modes, which compare very well to results from perturbation theory. The Einstein equatio...

  2. A Binary Teetering on the Edge

    Science.gov (United States)

    Motl, P. M.; D'Souza, M. C. R.; Tohline, J. E.; Frank, J.

    2005-05-01

    We present a fully three-dimensional hydrodynamical simulation of Roche lobe overflow in a binary near the stability boundary. This boundary separates evolutionary branches that correspond to either an accelerating mass transfer rate leading eventually to merger through tidal instability or to a decaying mass transfer rate as the orbit expands. The binary begins with a mass ratio of 0.4 (ratio of donor to accretor mass) and is initially assumed to be rotating synchronously. We treat the stellar components as simple polytropic fluids characterized by a polytropic index, n = 3/2. As the donor overflows its Roche lobe, the mass transfer rate initially accelerates before stabilizing and eventually dropping over a timescale of tens of orbits. We also note that for this particular binary, the accretion stream impacts on the surface of the donor rather than forming an accretion disk. This simulation allows us to measure the efficiency with which the accretion stream spins up the accretor in this "direct impact" scenario and the degree to which angular momentum is transfered back to the binary orbit via the tidal field.

  3. Planet Scattering Around Binaries: Ejections, Not Collisions

    Science.gov (United States)

    Smullen, Rachel A.; Kratter, Kaitlin M.; Shannon, Andrew

    2016-06-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary star and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Systems similar to the only observed multi-planet circumbinary system, Kepler-47, can arise from much more tightly packed, unstable systems. Only extreme initial conditions introduce differences in the final planet populations. Thus, we suggest that any intrinsic differences in the populations are imprinted by formation.

  4. Orbital velocity

    CERN Document Server

    Modestino, Giuseppina

    2016-01-01

    The trajectory and the orbital velocity are determined for an object moving in a gravitational system, in terms of fundamental and independent variables. In particular, considering a path on equipotential line, the elliptical orbit is naturally traced, verifying evidently the keplerian laws. The case of the planets of the solar system is presented.

  5. Spectroscopic Binaries: Towards the 100-Year Time Domain

    Science.gov (United States)

    Griffin, R. F.

    2012-04-01

    Good measurements of visual binary stars (position angle and angular separation) have been made for nearly 200 years. Radial-velocity observers have exhibited less patience; when the orbital periods of late-type stars in the catalogue published in 1978 are sorted into bins half a logarithmic unit wide, the modal bin is the one with periods between 3 and 10 days. The same treatment of the writer's orbits shows the modal bin to be the one between 1000 and 3000 days. Of course the spectroscopists cannot quickly catch up the 200 years that the visual observers have been going, but many spectroscopic orbits with periods of decades, and a few of the order of a century, have been published. Technical developments have also been made in `visual' orbit determination, and orbits with periods of only a few days have been determined for certain `visual' binaries. In principle, therefore, the time domains of visual and spectroscopic binaries now largely overlap. Overlap is essential, as it is only by combining both techniques that orbits can be determined in three dimensions, as is necessary for the important objective of determining stellar masses accurately. Nevertheless the actual overlap-objects with accurate measurements by both techniques-remains disappointingly small. There have, however, been unforeseen benefits from the observation of spectroscopic binaries that have unconventionally long orbital periods, not a few of which have proved to be interesting and significant objects in their own right. It has also been shown that binary membership is more common than was once thought (orbits have even been determined for some of the IAU standard radial-velocity stars!); a recent study of the radial velocities of K giants that had been monitored for 45 years found a binary incidence of 30%, whereas a figure of 13.7% was given as recently as 2005 for a similar group.

  6. On the possible turbulence mechanism in accretion disks in nonmagnetic binary stars

    International Nuclear Information System (INIS)

    One of the major challenges in modern astrophysics is the unexplained turbulence of gas-dynamic (nonmagnetic) accretion disks. Since they are stable, such disks should not theoretically be turbulent, but observations show they are. The search for instabilities that can develop into turbulence is one of the most intriguing problems in modern astrophysics. In 2004, we pointed to the formation of the so-called 'precessional' density wave in accretion disks of binary stars, which produces additional density and velocity gradients in the disk. A linear hydrodynamics stability analysis of an accretion disk in a binary shows that the presence in the disk of a precessional wave produced by the tidal influence of the second binary component gives rise to the instability of radial modes, whose characteristic growth times are about one tenth or one hundredth of the binary's orbital period. The immediate reason for the instability is the radial velocity gradient in the precessional wave, the destabilizing perturbations being those in which the radial velocity variation on the wavelength scale is near or greater than the speed of sound. Unstable perturbations occur in the interior of the disk and make the gas turbulent as they propagate outward. The characteristic turbulence parameters are in agreement with observations (the Shakura–Sunyaev parameter (α≲0.01). (physics of our days)

  7. The formation and gravitational-wave detection of massive stellar black hole binaries

    International Nuclear Information System (INIS)

    If binaries consisting of two ∼100 M☉ black holes exist, they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z ∼ 2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by the recent discovery of several ≳ 150 M☉ stars in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black hole-black hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black hole-black hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.

  8. The formation and gravitational-wave detection of massive stellar black hole binaries

    Energy Technology Data Exchange (ETDEWEB)

    Belczynski, Krzysztof; Walczak, Marek [Astronomical Observatory, Warsaw University, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Buonanno, Alessandra [Maryland Center for Fundamental Physics and Joint Space-Science Institute, Department of Physics, University of Maryland, College Park, MD 20742 (United States); Cantiello, Matteo [Kavli Institute for Theoretical Physics, University of California, Kohn Hall, Santa Barbara, CA 93106 (United States); Fryer, Chris L. [Computational Computer Science Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Holz, Daniel E. [Enrico Fermi Institute, Department of Physics, and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Mandel, Ilya [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Miller, M. Coleman, E-mail: kbelczyn@astrouw.edu.pl [Department of Astronomy and Joint Space-Science Institute University of Maryland, College Park, MD 20742-2421 (United States)

    2014-07-10

    If binaries consisting of two ∼100 M{sub ☉} black holes exist, they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z ∼ 2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by the recent discovery of several ≳ 150 M{sub ☉} stars in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black hole-black hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black hole-black hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.

  9. Binaries migrating in a gaseous disk: Where are the Galactic center binaries?

    CERN Document Server

    Baruteau, C; Lin, D N C

    2010-01-01

    The massive stars in the Galactic center inner arcsecond share analogous properties with the so-called Hot Jupiters. Most of these young stars have highly eccentric orbits, and were probably not formed in-situ. It has been proposed that these stars acquired their current orbits from the tidal disruption of compact massive binaries scattered toward the proximity of the central supermassive black hole. Assuming a binary star formed in a thin gaseous disk beyond 0.1 pc from the central object, we investigate the relevance of disk-satellite interactions to harden the binding energy of the binary, and to drive its inward migration. A massive, equal-mass binary star is found to become more tightly wound as it migrates inwards toward the central black hole. The migration timescale is very similar to that of a single-star satellite of the same mass. The binary's hardening is caused by the formation of spiral tails lagging the stars inside the binary's Hill radius. We show that the hardening timescale is mostly determ...

  10. Binary black holes' effects on electromagnetic fields.

    Science.gov (United States)

    Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David

    2009-08-21

    In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. PMID:19792706

  11. Photometric constraints on binary asteroid dynamics

    Science.gov (United States)

    Scheirich, Peter

    2015-08-01

    To date, about 50 binary NEAs, 20 Mars-crossing and 80 small MB asteroids are known. We observe also a population of about 200 unbound asteroid systems (asteroid pairs). I will review the photometric observational data we have for the best observed cases and compare them with theories of binary and paired asteroids evolution.The observed characteristics of asteroid systems suggest their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits of observed binary systems are non-random; the orbital poles concentrate near the obliquities of 0 and 180 degrees, i.e., near the YORP asymptotic states.Recently, a significant excess of retrograde satellite orbits was detected, which is not yet explained characteristic.An evolution of binary system depend heavily on the BYORP effect. If BYORP is contractive, the primary and secondary could end in a tidal-BYORP equilibrium. Observations of mutual events between binary components in at least four apparitions are needed for BYORP to be revealed by detecting a quadratic drift in mean anomaly of the satellite. I will show the observational evidence of single-synchronous binary asteroid with tidally locked satellite (175706 1996 FG3), i.e, with the quadratic drift equal to zero, and binary asteroid with contracting orbit (88710 2001 SL9), with positive value of the quadratic drift (the solution for the quadratic drift is ambiguous so far, with possible values of 5 and 8 deg/yr2).The spin configuration of the satellite play a crucial role in the evolution of the system under the influence of the BYORP effect. I will show that the rotational lightcurves of the satellites show that most of them have small libration amplitudes (up to 20 deg.), with a few interesting exceptions.Acknowledgements: This work has been supported by the Grant Agency of the Czech Republic, Grant P209

  12. Apsidal motion in eclipsing binary GG Orionis

    Science.gov (United States)

    Yilan, E.; Bulut, I.

    2016-03-01

    The study of apsidal motion in binary stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric eclipsing binary GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Giménez and García-Pelayo (1983) has been used for the apsidal motion analysis.

  13. Polarisation modulation in X-ray binaries

    Science.gov (United States)

    Ingram, Adam; Maccarone, Thomas

    2016-07-01

    X-ray polarimetry promises to provide a powerful new lever arm for studying accretion onto black holes with the next generation of X-ray telescopes. I will discuss how polarisation can be used to help constrain the physical origin of quasi-periodic oscillations (QPOs) observed in the X-ray light curves of accreting black holes. QPOs may be signatures of the frame dragging effect: in General Relativity, a spinning black hole twists up the surrounding space-time, causing vertical precession of nearby orbits. In the truncated disc / precessing inner flow model, the entire inner accretion flow precesses as a solid body causing a modulation in the X-ray flux through solid angle and Doppler effects. This model also predicts the observed polarisation of the X-ray signal to vary quasi-periodically. I will summarise our work to model the polarisation signal from a precessing accretion flow, starting with simple assumptions about the emission mechanism but taking General Relativity fully into account. We find that it should be possible to measure the predicted modulation in polarisation degree for a reasonable region of parameter space with a polarimeter capable of detecting ~60 counts per second from a bright black hole binary. I will also show that sensitivity can be greatly improved by correlating the signal with a high count rate reference band signal.

  14. Tidally distorted accretion discs in binary stars

    Science.gov (United States)

    Ogilvie, G. I.

    2002-03-01

    The non-axisymmetric features observed in the discs of dwarf novae in outburst are usually considered to be spiral shocks, which are the non-linear relatives of tidally excited waves. This interpretation suffers from a number of problems. For example, the natural site of wave excitation lies outside the Roche lobe, the disc must be especially hot, and most treatments of wave propagation do not take into account the vertical structure of the disc. In this paper I construct a detailed semi-analytical model of the non-linear tidal distortion of a thin, three-dimensional accretion disc by a binary companion on a circular orbit. The analysis presented here allows for vertical motion and radiative energy transport, and introduces a simple model for the turbulent magnetic stress. The m=2 inner vertical resonance has an important influence on the amplitude and phase of the tidal distortion. I show that the observed patterns find a natural explanation if the emission is associated with the tidally thickened sectors of the outer disc, which may be irradiated from the centre. According to this hypothesis, it may be possible to constrain the physical parameters of the disc through future observations.

  15. Absolute properties of the main-sequence eclipsing binary FM Leo

    CERN Document Server

    Ratajczak, M; Schwarzenberg-Czerny, A; Dimitrov, W; Konacki, M; Helminiak, K G; Bartczak, P; Fagas, M; Kaminski, K; Kankiewicz, P; Borczyk, W; Rozek, A

    2009-01-01

    First spectroscopic and new photometric observations of the eclipsing binary FM Leo are presented. The main aims were to determine orbital and stellar parameters of two components and their evolutionary stage. First spectroscopic observations of the system were obtained with DDO and PST spectrographs. The results of the orbital solution from radial velocity curves are combined with those derived from the light-curve analysis (ASAS-3 photometry and supplementary observations of eclipses with 1 m and 0.35 m telescopes) to derive orbital and stellar parameters. JKTEBOP, Wilson-Devinney binary modelling codes and a two-dimensional cross-correlation (TODCOR) method were applied for the analysis. We find the masses to be M_1 = 1.318 $\\pm$ 0.007 and M_2 = 1.287 $\\pm$ 0.007 M_sun, the radii to be R_1 = 1.648 $\\pm$ 0.043 and R_2 = 1.511 $\\pm$ 0.049 R_sun for primary and secondary stars, respectively. The evolutionary stage of the system is briefly discussed by comparing physical parameters with current stellar evoluti...

  16. RY Aquarius a Binary System with Pulsating delta-scuti Primary Component

    Science.gov (United States)

    Manzoori, Davood; Salar, Abbasvand

    2016-07-01

    We present simultaneous new BVI light curves along with radial velocity curve analysis of the RY Aqr system, using the PHysics Of Eclipsing BinariEs code. The analysis indicates that while the primary is completely inside its Roche critical surface, the secondary has filled out its Roche surface. In addition, the positions of the system components on M–R, H–R diagrams are specified, which show that the primary is a main-sequence or nearly main-sequence star while the secondary is an evolved subgiant. In addition, analysis of the period and luminosity variations of the system were carried out. Fourier frequency analysis of light variation indicates that the primary is a pulsating, δ-scuti variable star. Moreover, O–C curve analysis shows that the period of the system is secularly decreasing with a rate of dp/dt = 0.074 s yr‑1. This decrease in the orbital period variations was attributed to a mass and angular momentum loss from the system with a rate of 2.57× {10}-10{M}ȯ {{yr}}-1. Apart from the secular period decreases, the orbital period of the system is modulated by a cyclic period of 72.69 year, which was attributed to a third body orbiting around the barycenter of the system.

  17. The Absolute Parameters of The Detached Eclipsing Binary V482 Per

    CERN Document Server

    Basturk, Ozgur; Liakos, Alexios; Nelson, Robert H; Gazeas, Kosmas; Ozavci, Ibrahim; Yilmaz, Mesut; Senavci, Hakan V; Zakrzewski, Bartek

    2015-01-01

    We present the results of the spectroscopic, photometric and orbital period variation analyses of the detached eclipsing binary \\astrobj{V482~Per}. We derived the absolute parameters of the system (M$_{1}$ = 1.51 M$_{\\odot}$, M$_{2}$ = 1.29 M$_{\\odot}$, R$_{1}$ = 2.39 R$_{\\odot}$, R$_{2}$ = 1.45 R$_{\\odot}$, L$_{1}$ = 10.15 L$_{\\odot}$, L$_{2}$ = 3.01 L$_{\\odot}$) for the first time in literature, based on an analysis of our own photometric and spectroscopic observations. We confirm the nature of the variations observed in the system's orbital period, suggested to be periodic by earlier works. A light time effect due to a physically bound, star-sized companion (M$_{3}$ = 2.14 M$_{\\odot}$) on a highly eccentric (e = 0.83) orbit, seems to be the most likely cause. We argue that the companion can not be a single star but another binary instead. We calculated the evolutionary states of the system's components, and we found that the primary is slightly evolving after the Main Sequence, while the less massive secon...

  18. Binary effectivity rules

    DEFF Research Database (Denmark)

    Keiding, Hans; Peleg, Bezalel

    2006-01-01

    Abstract  A social choice rule (SCR) is a collection of social choice correspondences, one for each agenda. An effectivity rule is a collection of effectivity functions, one for each agenda. We prove that every monotonic and superadditive effectivity rule is the effectivity rule of some SCR. A SCR...... is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...... effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann-Morgenstern solutions play an important role in this characterization...

  19. A Quintuple Star System Containing Two Eclipsing Binaries

    CERN Document Server

    Rappaport, S; Kalomeni, B; Borkovits, T; Latham, D; Bieryla, A; Ngo, H; Mawet, D; Howell, S; Horch, E; Jacobs, T L; LaCourse, D; Sodor, A; Vanderburg, A; Pavlovski, K

    2016-01-01

    We present a quintuple star system that contains two eclipsing binaries. The unusual architecture includes two stellar images separated by 11" on the sky: EPIC 212651213 and EPIC 212651234. The more easterly image (212651213) actually hosts both eclipsing binaries which are resolved within that image at 0.09", while the westerly image (212651234) appears to be single in adaptive optics (AO), speckle imaging, and radial velocity (RV) studies. The 'A' binary is circular with a 5.1-day period, while the 'B' binary is eccentric with a 13.1-day period. The gamma velocities of the A and B binaries are different by ~10 km/s. That, coupled with their resolved projected separation of 0.09", indicates that the orbital period and separation of the 'C' binary (consisting of A orbiting B) are ~65 years and ~25 AU, respectively, under the simplifying assumption of a circular orbit. Motion within the C orbit should be discernible via future RV, AO, and speckle imaging studies within a couple of years. The C system (i.e., 21...

  20. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

  1. Projected Constraints on Scalarization with Gravitational Waves from Neutron Star Binaries

    CERN Document Server

    Sampson, Laura; Cornish, Neil; Ponce, Marcelo; Barausse, Enrico; Klein, Antoine; Palenzuela, Carlos; Lehner, Luis

    2014-01-01

    Certain scalar-tensor theories have the property of endowing stars with scalar hair, sourced either by the star's own compactness (spontaneous scalarization) or, for binary systems, by the companion's scalar hair (induced scalarization) or by the orbital binding energy (dynamical scalarization). Scalarized stars in binaries present different conservative dynamics than in General Relativity, and can also excite a scalar mode in the metric perturbation that carries away dipolar radiation. As a result, the binary orbit shrinks faster than predicted in General Relativity, modifying the rate of decay of the orbital period. In spite of this, scalar-tensor theories can pass existing binary pulsar tests, because observed pulsars may not be compact enough or sufficiently orbitally bound to activate scalarization. Gravitational waves emitted during the last stages of compact binary inspirals are thus ideal probes of scalarization effects. For the standard projected sensitivity of advanced LIGO, we here show that, if ne...

  2. SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

    International Nuclear Information System (INIS)

    Here we discuss the evolution of binaries around massive black holes (MBHs) in nuclear stellar clusters. We focus on their secular evolution due to the perturbation by the MBHs, while simplistically accounting for their collisional evolution. Binaries with highly inclined orbits with respect to their orbits around MBHs are strongly affected by secular processes, which periodically change their eccentricities and inclinations (e.g., Kozai-Lidov cycles). During periapsis approach, dissipative processes such as tidal friction may become highly efficient, and may lead to shrinkage of a binary orbit and even to its merger. Binaries in this environment can therefore significantly change their orbital evolution due to the MBH third-body perturbative effects. Such orbital evolution may impinge on their later stellar evolution. Here we follow the secular dynamics of such binaries and its coupling to tidal evolution, as well as the stellar evolution of such binaries on longer timescales. We find that stellar binaries in the central parts of nuclear stellar clusters (NSCs) are highly likely to evolve into eccentric and/or short-period binaries, and become strongly interacting binaries either on the main sequence (at which point they may even merge), or through their later binary stellar evolution. The central parts of NSCs therefore catalyze the formation and evolution of strongly interacting binaries, and lead to the enhanced formation of blue stragglers, X-ray binaries, gravitational wave sources, and possible supernova progenitors. Induced mergers/collisions may also lead to the formation of G2-like cloud-like objects such as the one recently observed in the Galactic center

  3. SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

    Energy Technology Data Exchange (ETDEWEB)

    Prodan, Snezana; Antonini, Fabio [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada); Perets, Hagai B., E-mail: sprodan@cita.utoronto.ca, E-mail: antonini@cita.utoronto.ca [Physics Department, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2015-02-01

    Here we discuss the evolution of binaries around massive black holes (MBHs) in nuclear stellar clusters. We focus on their secular evolution due to the perturbation by the MBHs, while simplistically accounting for their collisional evolution. Binaries with highly inclined orbits with respect to their orbits around MBHs are strongly affected by secular processes, which periodically change their eccentricities and inclinations (e.g., Kozai-Lidov cycles). During periapsis approach, dissipative processes such as tidal friction may become highly efficient, and may lead to shrinkage of a binary orbit and even to its merger. Binaries in this environment can therefore significantly change their orbital evolution due to the MBH third-body perturbative effects. Such orbital evolution may impinge on their later stellar evolution. Here we follow the secular dynamics of such binaries and its coupling to tidal evolution, as well as the stellar evolution of such binaries on longer timescales. We find that stellar binaries in the central parts of nuclear stellar clusters (NSCs) are highly likely to evolve into eccentric and/or short-period binaries, and become strongly interacting binaries either on the main sequence (at which point they may even merge), or through their later binary stellar evolution. The central parts of NSCs therefore catalyze the formation and evolution of strongly interacting binaries, and lead to the enhanced formation of blue stragglers, X-ray binaries, gravitational wave sources, and possible supernova progenitors. Induced mergers/collisions may also lead to the formation of G2-like cloud-like objects such as the one recently observed in the Galactic center.

  4. Stability and Coalescence of Massive Twin Binaries

    CERN Document Server

    Hwang, Jason A; Rasio, Frederic A; Kalogera, Vassiliki

    2015-01-01

    Massive stars are usually found in binaries, and binaries with periods less than 10 days may have a preference for near equal component masses. In this paper we investigate the evolution of these binaries all the way to contact and the possibility that these systems can be progenitors of double neutron star binaries. The small orbital separations of observed double neutron star binaries suggest that the progenitor systems underwent a common envelope phase at least once during their evolution. Bethe & Brown (1998) proposed that massive binary twins will undergo a common envelope evolution while both components are ascending the red giant branch or asymptotic giant branch simultaneously, also known as double-core evolution. Using models generated from the stellar evolution code Evolve Zero Age Main Sequence, we determine the range of mass ratios resulting in both components simultaneously ascending the RGB or AGB as a function of the difference in birth times, t. We find that, even for a generous t=5 Myr, t...

  5. Spectroscopic subsystems in nearby wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5-m telescope to study short-period systems. Data reduction is described, mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, for some of them orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67pc. It is found that 43 binaries contain at least one subsystem and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods match the simple prescription proposed by the author (2014, AJ, 147, 87). The remaining 53 simple wide binaries with a median projected separation of 1300AU have the distri...

  6. PHYSICS

    CERN Multimedia

    P. Sphicas

    There have been three physics meetings since the last CMS week: “physics days” on March 27-29, the Physics/ Trigger week on April 23-27 and the most recent physics days on May 22-24. The main purpose of the March physics days was to finalize the list of “2007 analyses”, i.e. the few topics that the physics groups will concentrate on for the rest of this calendar year. The idea is to carry out a full physics exercise, with CMSSW, for select physics channels which test key features of the physics objects, or represent potential “day 1” physics topics that need to be addressed in advance. The list of these analyses was indeed completed and presented in the plenary meetings. As always, a significant amount of time was also spent in reviewing the status of the physics objects (reconstruction) as well as their usage in the High-Level Trigger (HLT). The major event of the past three months was the first “Physics/Trigger week” in Apri...

  7. HD 51844: An Am delta Scuti in a binary showing periastron brightening

    CERN Document Server

    Hareter, M; Weiss, W W; Hernández, A García; Borkovits, T; Lampens, P; Rainer, M; De Cat, P; Marcos-Arenal, P; Vos, J; Poretti, E; Baglin, A; Michel, E; Baudin, F; Catala, C

    2014-01-01

    Pulsating stars in binary systems are ideal laboratories to test stellar evolution and pulsation theory, since a direct, model-independent determination of component masses is possible. The high-precision CoRoT photometry allows a detailed view of the frequency content of pulsating stars, enabling detection of patterns in their distribution. The object HD 51844 is such a case showing periastron brightening instead of eclipses. We present a comprehensive study of the HD 51844 system, where we derive physical parameters of both components, the pulsation content and frequency patterns. Additionally, we obtain the orbital elements, including masses, and the chemical composition of the stars. Time series analysis using standard tools was mployed to extract the pulsation frequencies. Photospheric abundances of 21 chemical elements were derived by means of spectrum synthesis. We derived orbital elements both by fitting the observed radial velocities and the light curves, and we did asteroseismic modelling as well. W...

  8. Spectroscopic Binaries near the North Galactic Pole Paper 24: HD 106104, 109281, 109463 and 110743

    Indian Academy of Sciences (India)

    R. F. Griffin

    2001-06-01

    The four stars treated in this paper have been under observation with photoelectric radial-velocity spectrometers for many years. They have proved to be binaries with periods of 30, 1828, 1514 and 822 days respectively; the orbits are of modest eccentricity apart from that of HD 110743 which is indistinguishable from a circle. The mass functions are small, and no companion has been observed for any of the stars. HD 110743, a K dwarf, is much the nearest of the four, and its orbit is of short enough period for the photocentric motion to have been recognized by Hipparcos. An eleventh-magnitude star rather more than 1' away from HD 106104 is shown to be a genuine physical companion, with practically identical radial velocity, proper motion and distance modulus, although the projected separation is about 13,000 AU.

  9. Aligned spins: orbital elements, decaying orbits, and last stable circular orbit to high post-Newtonian orders

    International Nuclear Information System (INIS)

    In this paper, the quasi-Keplerian parameterization for the case that spins and orbital angular momentum in a compact binary system are aligned or anti-aligned with the orbital angular momentum vector is extended to 3PN point-mass, next-to-next-to-leading order spin–orbit, next-to-next-to-leading order spin(1)–spin(2) and next-to-leading order spin-squared dynamics in the conservative regime. In a further step, we use the expressions for the radiative multipole moments with spin to leading order linear and quadratic in both spins to compute radiation losses of the orbital binding energy and angular momentum. Orbital averaged expressions for the decay of energy and eccentricity are provided. An expression for the last stable circular orbit is given in terms of the angular velocity-type variable x. (paper)

  10. Aligned Spins: Orbital Elements, Decaying Orbits, and Last Stable Circular Orbit to high post-Newtonian Orders

    CERN Document Server

    Tessmer, Manuel; Schäfer, Gerhard

    2012-01-01

    In this article the quasi-Keplerian parameterisation for the case that spins and orbital angular momentum in a compact binary system are aligned or anti-aligned with the orbital angular momentum vector is extended to 3PN point-mass, next-to-next-to-leading order spin-orbit, next-to-next-to-leading order spin(1)-spin(2), and next-to-leading order spin-squared dynamics in the conservative regime. In a further step, we use the expressions for the radiative multipole moments with spin to leading order linear and quadratic in both spins to compute radiation losses of the orbital binding energy and angular momentum. Orbital averaged expressions for the decay of energy and eccentricity are provided. An expression for the last stable circular orbit is given in terms of the angular velocity type variable $x$.

  11. GAIA survey of galactic eclipsing binaries

    OpenAIRE

    Zwitter, Tomaz

    2002-01-01

    General importance and capabilities of observations of eclipsing binaries by the forthcoming ESA mission GAIA are discussed. Availability of spectroscopic observations and a large number of photometric bands on board will make it possible to reliably determine physical parameters for $\\sim 10^5$ binary stars. It is stressed that current methods of object by object analysis will have to be modified and included in an automatic analysis pipeline.

  12. Foreign body orbital cyst

    DEFF Research Database (Denmark)

    Yazdanfard, Younes; Heegard, Steffen; Fledelius, Hans C.;

    2001-01-01

    Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology......Ophthalmology, penetrating orbital injury, orbital foreign body, ultrasound, computed tomography (CT), histology...

  13. Binary Black Hole Encounters, Gravitational Bursts and Maximum Final Spin

    CERN Document Server

    Washik, M C; Herrmann, F; Hinder, I; Shoemaker, D M; Laguna, P; Matzner, R A

    2008-01-01

    The spin of the final black hole in the coalescence of nonspinning black holes is determined by the ``residual'' orbital angular momentum of the binary. This residual momentum consists of the orbital angular momentum that the binary is not able to shed in the process of merging. We study the angular momentum radiated, the spin of the final black hole and the gravitational bursts in a series of orbits ranging from almost direct infall to numerous orbits before infall that exhibit multiple bursts of radiation in the merger process. We show that the final black hole gets a maximum spin parameter $a/M_h \\le 0.78$, and this maximum occurs for initial orbital angular momentum $L \\approx M^2_h$.

  14. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    International Nuclear Information System (INIS)

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886

  15. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

    2013-11-10

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

  16. Bowen-York Type Initial Data for Binaries with Neutron Stars

    CERN Document Server

    Clark, Michael

    2016-01-01

    A new approach to construct initial data for binary systems with neutron star components is introduced. The approach is a generalization of the puncture initial data method for binary black holes based on Bowen-York solutions to the momentum constraint. As with binary black holes, the method allows setting orbital configurations with direct input from post-Newtonian approximations and involves solving only the Hamiltonian constraint. The effectiveness of the method is demonstrated with evolutions of double neutron star and black hole -- neutron star binaries in quasi-circular orbits.

  17. The LMC eclipsing binary HV 2274 fundamental properties and comparison with evolutionary models

    CERN Document Server

    Ribas, I; Fitzpatrick, E L; De Warf, L E; Maloney, F P; Maurone, P A; Bradstreet, D H; Giménez, A; Pritchard, J D; Ribas, Ignasi; Guinan, Edward F.; Fitzpatrick, Edward L.; Warf, Laurence E. De; Maloney, Frank P.; Maurone, Philip A.; Bradstreet, David H.; Gimenez, Alvaro; Pritchard, John D.

    1999-01-01

    We are carrying out an international, multi-wavelength program to determine the fundamental properties and independent distance estimates of selected eclipsing binaries in the LMC and SMC. Eclipsing binaries with well-defined double-line radial velocity curves and light curves provide valuable information on orbital and physical properties of their component stars. The study of stars in the LMC and SMC where the metal abundances are significantly lower than solar provides an important opportunity to test stellar atmosphere, interior and evolution models, and opacities. For the first time, we can also measure direct M-L relations for stars outside our Galaxy. In this paper we concentrate on the determination of the orbital and physical properties of HV 2274 from analyses of light curves and new radial velocity curves formed from HST/GHRS observations. From UV/optical spectrophotometry of HV 2274 obtained with HST/FOS, the temperatures and the metallicity of the stars were found, as well as the interstellar ext...

  18. Study on thermo physical and excess molar properties of binary systems of ionic liquids. I: [Cnmim][PF6] (n = 6, 8) and alkyl acetates

    International Nuclear Information System (INIS)

    Highlights: • Densities, speeds of sound and refractive indices were reported for [Cnmim][PF6] (n = 6, 8) + alkyl acetates. • The measurements were performed at T = 5 K interval between (293.15 and 323) K over full range of concentrations. • Excess molar properties were derived from measured values of density, speed of sound and refractive index. • The effects of temperature and chain length of IL and acetate on excess molar properties were discussed. • Excess molar volumes VmE were predicted by PFP theory. - Abstract: The measurements of densities, ρ, speeds of sound, u and refractive indices, nD for binary mixtures containing 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6mim][PF6]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) + ethyl acetate (EA) and butyl acetate (BA) were reported over full range of concentrations. The measurements were performed at atmospheric pressure and seven different temperatures of five degree intervals between (293.15 and 323.15) K. The excess properties on mixing were derived from measured values of these properties. The values of density were utilized to obtain excess molar volumes, VmE, speeds of sound to obtain excess molar isentropic compressibilities, κS,mE and refractive index to get refractive index deviations, ΔφnD. The binary co-efficients of excess properties were obtained by Redlich–Kister polynomial equation. The influences of temperature and addition of –CH2 group in imidazolium cation of ionic liquids as well as acetate on excess properties have been discussed. The VmE and κS,mE are negative and decease with increase in temperature while ΔφnD are positive and increase with increase in temperature. For common acetate, The VmE increases with each increment of –CH2 group in imidazolium cation of IL and similar is true when –CH2 group increases in alkyl acetate for common IL. The deviation in VmEwas investigated by employing Prigogine–Flory–Patterson theory

  19. PHYSICS

    CERN Document Server

    D. Acosta

    2010-01-01

    A remarkable amount of progress has been made in Physics since the last CMS Week in June given the exponential growth in the delivered LHC luminosity. The first major milestone was the delivery of a variety of results to the ICHEP international conference held in Paris this July. For this conference, CMS prepared 15 Physics Analysis Summaries on physics objects and 22 Summaries on new and interesting physics measurements that exploited the luminosity recorded by the CMS detector. The challenge was incorporating the largest batch of luminosity that was delivered only days before the conference (300 nb-1 total). The physics covered from this initial running period spanned hadron production measurements, jet production and properties, electroweak vector boson production, and even glimpses of the top quark. Since then, the accumulated integrated luminosity has increased by a factor of more than 100, and all groups have been working tremendously hard on analysing this dataset. The September Physics Week was held ...

  20. Hybrid Black-Hole Binary Initial Data

    Science.gov (United States)

    Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-01-01

    "Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

  1. Nonlinear Tides in Close Binary Systems

    CERN Document Server

    Weinberg, Nevin N; Quataert, Eliot; Burkart, Josh

    2011-01-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct effects: three-mode nonlinear interactions and nonlinear excitation of modes by the time-varying gravitational potential of the companion. This paper presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism is applicable to binaries containing stars, planets, or compact objects, we focus on solar type stars with stellar or planetary companions. Our primary results include: (1) The linear tidal solution often used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited gravity waves are unstable to parametric resonance for companion masses M' > 10-100 M_Earth at orbital periods P = 1-10 days. The nearly static equilibrium tide is, however, parametrically s...

  2. Supermassive Black Hole Binaries as Galactic Blenders

    CERN Document Server

    Kandrup, H E; Terzic, B; Bohn, C L; Kandrup, Henry E.; Sideris, Ioannis V.; Terzic, Balsa; Bohn, Courtlandt L.

    2003-01-01

    This paper focuses on the dynamical implications of close supermassive black hole binaries both as an example of resonant phase mixing and as a potential explanation of inversions and other anomalous features observed in the luminosity profiles of some elliptical galaxies. The presence of a binary comprised of black holes executing nearly periodic orbits leads to the possibility of a broad resonant coupling between the black holes and various stars in the galaxy. This can result in efficient chaotic phase mixing and, in many cases, systematic increases in the energies of stars and their consequent transport towards larger radii. Allowing for the presence of a supermassive black hole binary with plausible parameter values near the center of a spherical, or nearly spherical, galaxy characterised initially by a Nuker density profile enables one to reproduce in considerable detail the central surface brightness distributions of such galaxies as NGC 3706.

  3. Classification of Stellar Orbits in Axisymmetric Galaxies

    CERN Document Server

    Li, Baile; Khan, Fazeel

    2014-01-01

    It is known that two supermassive black holes (SMBHs) cannot merge in a spherical galaxy within a Hubble time; an emerging picture is that galaxy geometry, rotation, and large potential perturbations may usher the SMBH binary through the critical three-body scattering phase and ultimately drive the SMBH to coalesce. We explore the orbital content within an N-body model of a mildly- flattened, non-rotating, SMBH-embedded elliptical galaxy. When used as the foundation for a study on the SMBH binary coalescence, the black holes bypassed the binary stalling often seen within spherical galaxies and merged on Gyr timescales (Khan et al. 2013). Using both frequency-mapping and angular momentum criteria, we identify a wealth of resonant orbits in the axisymmetric model, including saucers, that are absent from an otherwise identical spherical system and that can potentially interact with the binary. We quantified the set of orbits that could be scattered by the SMBH binary, and found that the axisymmetric model contai...

  4. Binary black hole spectroscopy

    International Nuclear Information System (INIS)

    We study parameter estimation with post-Newtonian (PN) gravitational waveforms for the quasi-circular, adiabatic inspiral of spinning binary compact objects. In particular, the performance of amplitude-corrected waveforms is compared with that of the more commonly used restricted waveforms, in Advanced LIGO and EGO. With restricted waveforms, the properties of the source can only be extracted from the phasing. In the case of amplitude-corrected waveforms, the spectrum encodes a wealth of additional information, which leads to dramatic improvements in parameter estimation. At distances of ∼100 Mpc, the full PN waveforms allow for high-accuracy parameter extraction for total mass up to several hundred solar masses, while with the restricted ones the errors are steep functions of mass, and accurate parameter estimation is only possible for relatively light stellar mass binaries. At the low-mass end, the inclusion of amplitude corrections reduces the error on the time of coalescence by an order of magnitude in Advanced LIGO and a factor of 5 in EGO compared to the restricted waveforms; at higher masses these differences are much larger. The individual component masses, which are very poorly determined with restricted waveforms, become measurable with high accuracy if amplitude-corrected waveforms are used, with errors as low as a few per cent in Advanced LIGO and a few tenths of a per cent in EGO. The usual spin-orbit parameter β is also poorly determined with restricted waveforms (except for low-mass systems in EGO), but the full waveforms give errors that are small compared to the largest possible value consistent with the Kerr bound. This suggests a way of finding out if one or both of the component objects violate this bound. On the other hand, we find that the spin-spin parameter σ remains poorly determined even when the full waveform is used. Generally, all errors have but a weak dependence on the magnitudes and orientations of the spins. We also briefly

  5. PHYSICS

    CERN Multimedia

    J. Incandela

    There have been numerous developments in the physics area since the September CMS week. The biggest single event was the Physics/Trigger week in the end of Octo¬ber, whereas in terms of ongoing activities the “2007 analyses” went into high gear. This was in parallel with participation in CSA07 by the physics groups. On the or¬ganizational side, the new conveners of the physics groups have been selected, and a new database for man¬aging physics analyses has been deployed. Physics/Trigger week The second Physics-Trigger week of 2007 took place during the week of October 22-26. The first half of the week was dedicated to working group meetings. The ple¬nary Joint Physics-Trigger meeting took place on Wednesday afternoon and focused on the activities of the new Trigger Studies Group (TSG) and trigger monitoring. Both the Physics and Trigger organizations are now focused on readiness for early data-taking. Thus, early trigger tables and preparations for calibr...

  6. PHYSICS

    CERN Multimedia

    P. Sphicas

    The CPT project came to an end in December 2006 and its original scope is now shared among three new areas, namely Computing, Offline and Physics. In the physics area the basic change with respect to the previous system (where the PRS groups were charged with detector and physics object reconstruction and physics analysis) was the split of the detector PRS groups (the old ECAL-egamma, HCAL-jetMET, Tracker-btau and Muons) into two groups each: a Detector Performance Group (DPG) and a Physics Object Group. The DPGs are now led by the Commissioning and Run Coordinator deputy (Darin Acosta) and will appear in the correspond¬ing column in CMS bulletins. On the physics side, the physics object groups are charged with the reconstruction of physics objects, the tuning of the simulation (in collaboration with the DPGs) to reproduce the data, the provision of code for the High-Level Trigger, the optimization of the algorithms involved for the different physics analyses (in collaboration with the analysis gr...

  7. Physics and chemistry of lithium halides in 1,3-dioxolane and its binary mixtures with acetonitrile probed by conductometric, volumetric, viscometric, refractometric and acoustic study

    International Nuclear Information System (INIS)

    Highlights: ► Lithium halide interaction in binary mixture of acetonitrile and 1,3-dioxolane. ► Triple-ion formation in 1,3-dioxolane. ► More ion–solvent interaction than ion–ion interaction in all the solvent mixture. ► Ion solvation is due to preferential solvation and dimerization of acetonitrile. - Abstract: Electrolytic conductance (Λ), density (ρ), viscosity (η), refractive index (nD) and ultrasonic speed (u) of lithium halides LiX (where X = Cl, Br, I) have been studied in different mass fraction (w1 = 0.00–0.75) of acetonitrile (ACN) + 1,3-dioxolane (1,3-DO) mixtures at 298.15 K. The limiting molar conductivity (Λ0), association constant (KA), and distance of closest approach of ions (R) have been evaluated using Fuoss-conductance equation (1978). The deviation of conductometric curve (Λ vs √c) from linearity in 1,3-DO, analyzed by the Fuoss–Kraus theory. The limiting apparent molar volume (φV0), experimental slope (SV*) derived from Masson equation, and viscosity B and A-coefficients derived from Jones–Dole equation supplemented with density and viscosity data, respectively, have been interpreted in terms of ion–solvent and ion–ion interactions. The limiting partial molar adiabatic compressibility (φK0), have also been obtained from the value of ultrasonic speed (u) and discussed them to interpret the same.

  8. Young and Waltzing Binary Stars

    Science.gov (United States)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  9. Binary pulsar - a test for general relativity

    International Nuclear Information System (INIS)

    The binary system of PSR1913 + 16 contains the pulsar and an, as yet unknown, companion. If this star is a compact object too, then the data can be interpreted in terms of general relativistic effects. This leads to the conclusion that the decay of the orbit must be due to the emission of gravitational waves. The nature of the unseen companion is discussed in detail

  10. Flip-flopping binary black holes.

    Science.gov (United States)

    Lousto, Carlos O; Healy, James

    2015-04-10

    We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of d≈25M between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for t=20 000M and displays a total change in the orientation of the spin of one of the black holes from an initial alignment with the orbital angular momentum to a complete antialignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 post-Newtonian equations of motion and spin evolution to show that this process continuously flip flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes. PMID:25910104

  11. Cassini states for black hole binaries

    Science.gov (United States)

    Correia, Alexandre C. M.

    2016-03-01

    Cassini states correspond to the equilibria of the spin axis of a body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black hole binary systems based on a Hamiltonian formalism. In absence of dissipation, the problem is integrable and it is easy to identify all possible trajectories for the spin for a given value of the total angular momentum. As the system collapses due to radiation reaction, the Cassini states are shifted to different positions, which modifies the dynamics around them. This is why the final spin distribution may differ from the initial one. Our method provides a simple way of predicting the distribution of the spin of black hole binaries at the end of the inspiral phase.

  12. Cassini states for black-hole binaries

    CERN Document Server

    Correia, Alexandre C M

    2016-01-01

    Cassini states correspond to equilibria of the spin axis of a celestial body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black-hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black-hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black-hole binary systems based on a Hamiltonian formalism. In absence of dissipation the problem is integrable and it is easy to identify all possible trajectories for the spin for a given value of the total angular momentum. As the system collapses due to radiation reaction, the Cassini states are shifted to different positions, which modifies the dynamics around them. This is why the final spin distribution may differ from the initial one. Our method provides a simple way of predicting the distribution of the spin of black-hole binaries at th...

  13. An Observational Study of Tidal Synchronization in Solar-Type Binary Stars in the Open Clusters M35 and M34

    CERN Document Server

    Meibom, S; Stassun, K G; Meibom, Soren; Mathieu, Robert D.; Stassun, Keivan G.

    2006-01-01

    We present rotation periods for the solar-type primary stars in 13 close (a \\~0) with the orbital motion. Of the six closest binaries two with circular orbits are not synchronized, one being subsynchronous and one being supersynchronous, and the primary stars in two binaries with eccentric orbits are rotating more slowly than pseudosynchronism. The remaining two binaries have reached the equilibrium state of both a circularized orbit and synchronized rotation. As a set, the six binaries present a challenging case study for tidal evolution theory, which in particular does not predict subsynchronous rotation in such close systems.

  14. Angular Momentum Transport in Double White Dwarf Binaries

    Science.gov (United States)

    Motl, Patrick M.; Tohline, J. E.; Frank, J.

    2006-12-01

    We present numerical simulations of dynamically unstable mass transfer in a double white dwarf binary with initial mass ratio, q = 0.4. The binary components are approximated as polytropes of index n = 3/2 and the synchronously rotating, semi-detached equilibrium binary is evolved hydrodynamically with the gravitational potential being computed through the solution of Poisson's equation. Upon initiating deep contact, the mass transfer rate grows by more than an order of magnitude over approximately ten orbits, as would be expected for dynamically unstable mass transfer. However, the mass transfer rate then reaches a peak value, the binary expands and the mass transfer event subsides. The binary must therefore have crossed the critical mass ratio for stability against dynamical mass transfer. Despite the initial loss of orbital angular momentum into the spin of the accreting star, we find that the accretor's spin saturates and angular momentum is returned to the orbit more efficiently than has been previously suspected for binaries in the direct impact accretion mode. To explore this surprising result, we directly measure the critical mass ratio for stability by imposing artificial angular momentum loss at various rates to drive the binary to an equilibrium mass transfer rate. For one of these driven evolutions, we attain equilibrium mass transfer and deduce that the mass ratio for stability is approximately 2/3. This is consistent with the result for mass transferring binaries that effectively return angular momentum to the orbit through an accretion disk. This work has been supported in part by NSF grants AST 04-07070 and PHY 03-26311 and in part through NASA's ATP program grant NAG5-13430. The computations were performed primarily at NCSA through grant MCA98N043 and at LSU's Center for Computation & Technology.

  15. PRECESSION. Dynamics of spinning black-hole binaries with python

    OpenAIRE

    Gerosa, Davide; Kesden, Michael

    2016-01-01

    We present the numerical code PRECESSION: a new open-source python module to study the dynamics of precessing black-hole binaries in the post-Newtonian regime. The code provides a comprehensive toolbox to (i) study the evolution of the black-hole spins along their precession cycles, (ii) perform gravitational-wave driven binary inspirals using both orbit-averaged and precession-averaged integrations, and (iii) predict the properties of the merger remnant through fitting formulae obtained from...

  16. Highlights on eclipsing binary variables from Araucaria Project

    Directory of Open Access Journals (Sweden)

    Karczmarek Paulina

    2015-01-01

    Full Text Available The Araucaria Project, which main goal is to provide precise determination of the cosmic distance scale, has recently made a set of discoveries involving variable stars in binary systems. Among these discoveries we highlight three: 1% precise measurement of a Cepheid's dynamical mass and its projection factor, accurate determination of both stellar and orbital parameters of eclipsing binary consisting of two Cepheid variables, and discovery of new class of variable stars, mimicking RR Lyrae pulsators.

  17. KIC 7177553: A Quadruple System of Two Close Binaries

    Science.gov (United States)

    Lehmann, H.; Borkovits, T.; Rappaport, S. A.; Ngo, H.; Mawet, D.; Csizmadia, Sz.; Forgács-Dajka, E.

    2016-03-01

    KIC 7177553 was observed by the Kepler satellite to be an eclipsing eccentric binary star system with an 18-day orbital period. Recently, an eclipse timing study of the Kepler binaries has revealed eclipse timing variations (ETVs) in this object with an amplitude of ˜100 s and an outer period of 529 days. The implied mass of the third body is that of a super-Jupiter, but below the mass of a brown dwarf. We therefore embarked on a radial velocity (RV) study of this binary to determine its system configuration and to check the hypothesis that it hosts a giant planet. From the RV measurements, it became immediately obvious that the same Kepler target contains another eccentric binary, this one with a 16.5-day orbital period. Direct imaging using adaptive optics reveals that the two binaries are separated by 0.″4 (˜167 AU) and have nearly the same magnitude (to within 2%). The close angular proximity of the two binaries and very similar γ velocities strongly suggest that KIC 7177553 is one of the rare SB4 systems consisting of two eccentric binaries where at least one system is eclipsing. Both systems consist of slowly rotating, nonevolved, solar-like stars of comparable masses. From the orbital separation and the small difference in γ velocity, we infer that the period of the outer orbit most likely lies in the range of 1000-3000 yr. New images taken over the next few years, as well as the high-precision astrometry of the Gaia satellite mission, will allow us to set much narrower constraints on the system geometry. Finally, we note that the observed ETVs in the Kepler data cannot be produced by the second binary. Further spectroscopic observations on a longer timescale will be required to prove the existence of the massive planet.

  18. PHYSICS

    CERN Multimedia

    Submitted by

    Physics Week: plenary meeting on physics groups plans for startup (14–15 May 2008) The Physics Objects (POG) and Physics Analysis (PAG) Groups presented their latest developments at the plenary meeting during the Physics Week. In the presentations particular attention was given to startup plans and readiness for data-taking. Many results based on the recent cosmic run were shown. A special Workshop on SUSY, described in a separate section, took place the day before the plenary. At the meeting, we had also two special DPG presentations on “Tracker and Muon alignment with CRAFT” (Ernesto Migliore) and “Calorimeter studies with CRAFT” (Chiara Rovelli). We had also a report from Offline (Andrea Rizzi) and Computing (Markus Klute) on the San Diego Workshop, described elsewhere in this bulletin. Tracking group (Boris Mangano). The level of sophistication of the tracking software increased significantly over the last few months: V0 (K0 and Λ) reconstr...

  19. Gamma-ray binaries and related systems

    CERN Document Server

    Dubus, Guillaume

    2013-01-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary (eta Car) have also been detected - 'related systems' that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common ? What drives their high-energy emission ? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants ? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as ...

  20. Angle resolved photoemission from organic semiconductors: orbital imaging beyond the molecular orbital interpretation

    OpenAIRE

    Dauth, M.; Wiessner, M.; Feyer, V.; Schöll, A.; Puschnig, P.; Reinert, F.; Kümmel, S.

    2015-01-01

    Fascinating pictures that can be interpreted as showing molecular orbitals have been obtained with various imaging techniques. Among these, angle resolved photoemission spectroscopy (ARPES) has emerged as a particularly powerful method. Orbital images have been used to underline the physical credibility of the molecular orbital concept. However, from the theory of the photoemission process it is evident that imaging experiments do not show molecular orbitals, but Dyson orbitals. The latter ar...