Dynamical Analysis of the Circumprimary Planet in the Eccentric Binary System HD 59686

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Trifonov, Trifon; Lee, Man Hoi; Reffert, Sabine; Quirrenbach, Andreas

2018-04-01

We present a detailed orbital and stability analysis of the HD 59686 binary-star planet system. HD 59686 is a single-lined, moderately close (a B = 13.6 au) eccentric (e B = 0.73) binary, where the primary is an evolved K giant with mass M = 1.9 M ⊙ and the secondary is a star with a minimum mass of m B = 0.53 M ⊙. Additionally, on the basis of precise radial velocity (RV) data, a Jovian planet with a minimum mass of m p = 7 M Jup, orbiting the primary on a nearly circular S-type orbit with e p = 0.05 and a p = 1.09 au, has recently been announced. We investigate large sets of orbital fits consistent with HD 59686's RV data by applying bootstrap and systematic grid search techniques coupled with self-consistent dynamical fitting. We perform long-term dynamical integrations of these fits to constrain the permitted orbital configurations. We find that if the binary and the planet in this system have prograde and aligned coplanar orbits, there are narrow regions of stable orbital solutions locked in a secular apsidal alignment with the angle between the periapses, Δω, librating about 0°. We also test a large number of mutually inclined dynamical models in an attempt to constrain the three-dimensional orbital architecture. We find that for nearly coplanar and retrograde orbits with mutual inclination 145° ≲ Δi ≤ 180°, the system is fully stable for a large range of orbital solutions.

THE NASA-UC ETA-EARTH PROGRAM. III. A SUPER-EARTH ORBITING HD 97658 AND A NEPTUNE-MASS PLANET ORBITING Gl 785

International Nuclear Information System (INIS)

Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard; Johnson, John Asher; Fischer, Debra A.; Wright, Jason T.; Henry, Gregory W.; Valenti, Jeff A.; Anderson, Jay; Piskunov, Nikolai E.

2011-01-01

We report the discovery of planets orbiting two bright, nearby early K dwarf stars, HD 97658 and Gl 785. These planets were detected by Keplerian modeling of radial velocities measured with Keck-HIRES for the NASA-UC Eta-Earth Survey. HD 97658 b is a close-in super-Earth with minimum mass Msin i = 8.2 ± 1.2 M + , orbital period P = 9.494 ± 0.005 days, and an orbit that is consistent with circular. Gl 785 b is a Neptune-mass planet with Msin i = 21.6 ± 2.0 M + , P = 74.39 ± 0.12 days, and orbital eccentricity e = 0.30 ± 0.09. Photometric observations with the T12 0.8 m automatic photometric telescope at Fairborn Observatory show that HD 97658 is photometrically constant at the radial velocity period to 0.09 mmag, supporting the existence of the planet.

On the Radii of Close-in Giant Planets.

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Burrows; Guillot; Hubbard; Marley; Saumon; Lunine; Sudarsky

2000-05-01

The recent discovery that the close-in extrasolar giant planet HD 209458b transits its star has provided a first-of-its-kind measurement of the planet's radius and mass. In addition, there is a provocative detection of the light reflected off of the giant planet tau Bootis b. Including the effects of stellar irradiation, we estimate the general behavior of radius/age trajectories for such planets and interpret the large measured radii of HD 209458b and tau Boo b in that context. We find that HD 209458b must be a hydrogen-rich gas giant. Furthermore, the large radius of a close-in gas giant is not due to the thermal expansion of its atmosphere but to the high residual entropy that remains throughout its bulk by dint of its early proximity to a luminous primary. The large stellar flux does not inflate the planet but retards its otherwise inexorable contraction from a more extended configuration at birth. This implies either that such a planet was formed near its current orbital distance or that it migrated in from larger distances (>/=0.5 AU), no later than a few times 107 yr of birth.

CAN TiO EXPLAIN THERMAL INVERSIONS IN THE UPPER ATMOSPHERES OF IRRADIATED GIANT PLANETS?

International Nuclear Information System (INIS)

Spiegel, David S.; Silverio, Katie; Burrows, Adam

2009-01-01

Spitzer Space Telescope infrared observations indicate that several transiting extrasolar giant planets have thermal inversions in their upper atmospheres. Above a relative minimum, the temperature appears to increase with altitude. Such an inversion probably requires a species at high altitude that absorbs a significant amount of incident optical/UV radiation. Some authors have suggested that the strong optical absorbers titanium oxide (TiO) and vanadium oxide (VO) could provide the needed additional opacity, but if regions of the atmosphere are cold enough for Ti and V to be sequestered into solids they might rain out and be severely depleted. With a model of the vertical distribution of a refractory species in gaseous and condensed form, we address the question of whether enough TiO (or VO) could survive aloft in an irradiated planet's atmosphere to produce a thermal inversion. We find that it is unlikely that VO could play a critical role in producing thermal inversions. Furthermore, we find that macroscopic mixing is essential to the TiO hypothesis; without macroscopic mixing, such a heavy species cannot persist in a planet's upper atmosphere. The amount of macroscopic mixing that is required depends on the size of condensed titanium-bearing particles that form in regions of an atmosphere that are too cold for gaseous TiO to exist. We parameterize the macroscopic mixing with the eddy diffusion coefficient K zz and find, as a function of particle size a, the values that K zz must assume on the highly irradiated planets HD 209458b, HD 149026b, TrES-4, and OGLE-TR-56b to loft enough titanium to the upper atmosphere for the TiO hypothesis to be correct. On these planets, we find that for TiO to be responsible for thermal inversions K zz must be at least a few times 10 7 cm 2 s -1 , even for a = 0.1 μm, and increases to nearly 10 11 cm 2 s -1 for a = 10 μm. Such large values may be problematic for the TiO hypothesis, but are not impossible.

Characterizing the X-ray Radiation Field in the Earth-like Planet Forming ExoSystem HD 113766

Science.gov (United States)

Lisse, Carey

2010-09-01

We propose a 100 ksec ACIS-S observation of the 12 Myr old system HD 113766, the site of on-going terrestrial planet formation (Lisse et al. 2008), in order to determine the spectrum of x-ray radiation in the fledgling system, its origin in the stellar coronae and proto-planetary disk, and its potential impact on the nascent planet.

A SECOND GIANT PLANET IN 3:2 MEAN-MOTION RESONANCE IN THE HD 204313 SYSTEM

International Nuclear Information System (INIS)

Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline; Horner, J.; Wittenmyer, Robert A.; Simon, Attila E.

2012-01-01

We present eight years of high-precision radial velocity (RV) data for HD 204313 from the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. The star is known to have a giant planet (Msin i = 3.5 M J ) on a ∼1900 day orbit, and a Neptune-mass planet at 0.2 AU. Using our own data in combination with the published CORALIE RVs of Ségransan et al., we discover an outer Jovian (Msin i = 1.6 M J ) planet with P ∼ 2800 days. Our orbital fit suggests that the planets are in a 3:2 mean motion resonance, which would potentially affect their stability. We perform a detailed stability analysis and verify that the planets must be in resonance.

A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host.

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Gaudi, B Scott; Stassun, Keivan G; Collins, Karen A; Beatty, Thomas G; Zhou, George; Latham, David W; Bieryla, Allyson; Eastman, Jason D; Siverd, Robert J; Crepp, Justin R; Gonzales, Erica J; Stevens, Daniel J; Buchhave, Lars A; Pepper, Joshua; Johnson, Marshall C; Colon, Knicole D; Jensen, Eric L N; Rodriguez, Joseph E; Bozza, Valerio; Novati, Sebastiano Calchi; D'Ago, Giuseppe; Dumont, Mary T; Ellis, Tyler; Gaillard, Clement; Jang-Condell, Hannah; Kasper, David H; Fukui, Akihiko; Gregorio, Joao; Ito, Ayaka; Kielkopf, John F; Manner, Mark; Matt, Kyle; Narita, Norio; Oberst, Thomas E; Reed, Phillip A; Scarpetta, Gaetano; Stephens, Denice C; Yeigh, Rex R; Zambelli, Roberto; Fulton, B J; Howard, Andrew W; James, David J; Penny, Matthew; Bayliss, Daniel; Curtis, Ivan A; DePoy, D L; Esquerdo, Gilbert A; Gould, Andrew; Joner, Michael D; Kuhn, Rudolf B; Labadie-Bartz, Jonathan; Lund, Michael B; Marshall, Jennifer L; McLeod, Kim K; Pogge, Richard W; Relles, Howard; Stockdale, Christopher; Tan, T G; Trueblood, Mark; Trueblood, Patricia

2017-06-22

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside, and is highly inflated-traits that have been linked to high insolation. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.

Infrared radiation from an extrasolar planet.

Science.gov (United States)

Deming, Drake; Seager, Sara; Richardson, L Jeremy; Harrington, Joseph

2005-04-07

A class of extrasolar giant planets--the so-called 'hot Jupiters' (ref. 1)--orbit within 0.05 au of their primary stars (1 au is the Sun-Earth distance). These planets should be hot and so emit detectable infrared radiation. The planet HD 209458b (refs 3, 4) is an ideal candidate for the detection and characterization of this infrared light because it is eclipsed by the star. This planet has an anomalously large radius (1.35 times that of Jupiter), which may be the result of ongoing tidal dissipation, but this explanation requires a non-zero orbital eccentricity (approximately 0.03; refs 6, 7), maintained by interaction with a hypothetical second planet. Here we report detection of infrared (24 microm) radiation from HD 209458b, by observing the decrement in flux during secondary eclipse, when the planet passes behind the star. The planet's 24-microm flux is 55 +/- 10 microJy (1sigma), with a brightness temperature of 1,130 +/- 150 K, confirming the predicted heating by stellar irradiation. The secondary eclipse occurs at the midpoint between transits of the planet in front of the star (to within +/- 7 min, 1sigma), which means that a dynamically significant orbital eccentricity is unlikely.

High-resolution spectroscopic search for the thermal emission of the extrasolar planet HD 217107 b

OpenAIRE

Cubillos, Patricio E.; Rojo, Patricio; Fortney, Jonathan J.

2011-01-01

We analyzed the combined near-infrared spectrum of a star-planet system with thermal emission atmospheric models, based on the composition and physical parameters of the system. The main objective of this work is to obtain the inclination of the orbit, the mass of the exoplanet, and the planet-to-star flux ratio. We present the results of our routines on the planetary system HD 217107, which was observed with the high-resolution spectrograph Phoenix at 2.14 microns. We revisited and tuned a c...

STABILITY OF ADDITIONAL PLANETS IN AND AROUND THE HABITABLE ZONE OF THE HD 47186 PLANETARY SYSTEM

International Nuclear Information System (INIS)

Kopparapu, Ravi Kumar; Raymond, Sean N.; Barnes, Rory

2009-01-01

We study the dynamical stability of an additional, potentially habitable planet in the HD 47186 planetary system. Two planets are currently known in this system: a 'hot Neptune' with a period of 4.08 days and a Saturn-mass planet with a period of 3.7 years. Here we consider the possibility that one or more undetected planets exist between the two known planets and possibly within the habitable zone (HZ) in this system. Given the relatively low masses of the known planets, additional planets could have masses ∼ + , and hence be terrestrial-like and further improving potential habitability. We perform N-body simulations to identify the stable zone between planets b and c and find that much of the inner HZ can harbor a 10 M + planet. With the current radial velocity threshold of ∼1 m s -1 , an additional planet should be detectable if it lies at the inner edge of the habitable zone at 0.8 AU. We also show that the stable zone could contain two additional planets of 10 M + each if their eccentricities are lower than ∼0.3.

THE NASA-UC ETA-EARTH PROGRAM. II. A PLANET ORBITING HD 156668 WITH A MINIMUM MASS OF FOUR EARTH MASSES

International Nuclear Information System (INIS)

Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard; Johnson, John Asher; Fischer, Debra A.; Wright, Jason T.; Henry, Gregory W.; Valenti, Jeff A.; Anderson, Jay; Piskunov, Nikolai E.

2011-01-01

We report the discovery of HD 156668 b, an extrasolar planet with a minimum mass of M P sin i = 4.15 M + . This planet was discovered through Keplerian modeling of precise radial velocities from Keck-HIRES and is the second super-Earth to emerge from the NASA-UC Eta-Earth Survey. The best-fit orbit is consistent with circular and has a period of P = 4.6455 days. The Doppler semi-amplitude of this planet, K = 1.89 m s -1 , is among the lowest ever detected, on par with the detection of GJ 581 e using HARPS. A longer period (P ∼ 2.3 years), low-amplitude signal of unknown origin was also detected in the radial velocities and was filtered out of the data while fitting the short-period planet. Additional data are required to determine if the long-period signal is due to a second planet, stellar activity, or another source. Photometric observations using the Automated Photometric Telescopes at Fairborn Observatory show that HD 156668 (an old, quiet K3 dwarf) is photometrically constant over the radial velocity period to 0.1 mmag, supporting the existence of the planet. No transits were detected down to a photometric limit of ∼3 mmag, ruling out transiting planets dominated by extremely bloated atmospheres, but not precluding a transiting solid/liquid planet with a modest atmosphere.

HD 89345: a bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

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Van Eylen, V.; Dai, F.; Mathur, S.; Gandolfi, D.; Albrecht, S.; Fridlund, M.; García, R. A.; Guenther, E.; Hjorth, M.; Justesen, A. B.; Livingston, J.; Lund, M. N.; Pérez Hernández, F.; Prieto-Arranz, J.; Regulo, C.; Bugnet, L.; Everett, M. E.; Hirano, T.; Nespral, D.; Nowak, G.; Palle, E.; Silva Aguirre, V.; Trifonov, T.; Winn, J. N.; Barragán, O.; Beck, P. G.; Chaplin, W. J.; Cochran, W. D.; Csizmadia, S.; Deeg, H.; Endl, M.; Heeren, P.; Grziwa, S.; Hatzes, A. P.; Hidalgo, D.; Korth, J.; Mathis, S.; Montañes Rodriguez, P.; Narita, N.; Patzold, M.; Persson, C. M.; Rodler, F.; Smith, A. M. S.

2018-05-01

We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with one-minute time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding the mass and radius to be 1.12^{+0.04}_{-0.01} M_⊙ and 1.657^{+0.020}_{-0.004} R_⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4^{+0.4}_{-1.3} Gyr, and the non-detection of mixed modes. The star hosts a "warm Saturn" (P = 11.8 days, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIES, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e ≈ 0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to conform to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

THE PECULIAR DEBRIS DISK OF HD 111520 AS RESOLVED BY THE GEMINI PLANET IMAGER

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Draper, Zachary H.; Matthews, Brenda C.; Gerard, Benjamin [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2 (Canada); Duchêne, Gaspard; Wang, Jason J.; Kalas, Paul; Graham, James R. [Department of Astronomy, UC Berkeley, Berkeley, CA 94720 (United States); Millar-Blanchaer, Maxwell A. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Padgett, Deborah [NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771 (United States); Ammons, S. Mark [Lawrence Livermore National Lab, 7000 East Ave., Livermore, CA 94551 (United States); Bulger, Joanna [Subaru Telescope, NAOJ, 650 North Aohoku Pl., Hilo, HI 96720 (United States); Chen, Christine; Greenbaum, Alexandra Z. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Chilcote, Jeffrey K. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, ON M5S 3H4 (Canada); Doyon, René [Institut de Recherche sur les Exoplanètes, Départment de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Fitzgerald, Michael P. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Follette, Kate B.; Macintosh, Bruce [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Hibon, Pascale [European Southern Observatory, Casilla 19001, Santiago 19 (Chile); Hinkley, Sasha [University of Exeter, Astrophysics Group, Physics Building, Stocker Rd., Exeter, EX4 4QL (United Kingdom); and others

2016-08-01

Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ∼30–100 AU in both total and polarized H -band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the observed disk emission. We employ three point-spread function subtraction methods to reduce the stellar glare and instrumental artifacts to confirm that there is a roughly 2:1 brightness asymmetry between the NW and SE extension. This specific feature makes HD 111520 the most extreme example of asymmetric debris disks observed in scattered light among similar highly inclined systems, such as HD 15115 and HD 106906. We further identify a tentative localized brightness enhancement and scale height enhancement associated with the disk at ∼40 AU away from the star on the SE extension. We also find that the fractional polarization rises from 10% to 40% from 0.″5 to 0.″8 from the star. The combination of large brightness asymmetry and symmetric polarization fraction leads us to believe that an azimuthal dust density variation is causing the observed asymmetry.

Two drastically different climate states on an Earth-like terra-planet

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S. Kalidindi

2018-06-01

Full Text Available We study an Earth-like terra-planet (water-limited terrestrial planet with an overland recycling mechanism bringing fresh water back from the high latitudes to the low latitudes. By performing model simulations for such a planet we find two drastically different climate states for the same set of boundary conditions and parameter values: a cold and wet (CW state with dominant low-latitude precipitation and a hot and dry (HD state with only high-latitude precipitation. We notice that for perpetual equinox conditions, both climate states are stable below a certain threshold value of background soil albedo while above the threshold only the CW state is stable. Starting from the HD state and increasing background soil albedo above the threshold causes an abrupt shift from the HD state to the CW state resulting in a sudden cooling of about 35 °C globally, which is of the order of the temperature difference between present day and the Snowball Earth state. When albedo starting from the CW state is reduced down to zero the terra-planet does not shift back to the HD state (no closed hysteresis. This is due to the high cloud cover in the CW state hiding the surface from solar irradiation so that surface albedo has only a minor effect on the top of the atmosphere radiation balance. Additional simulations with present-day Earth's obliquity all lead to the CW state, suggesting a similar abrupt transition from the HD state to the CW state when increasing obliquity from zero. Our study also has implications for the habitability of Earth-like terra-planets. At the inner edge of the habitable zone, the higher cloud cover in the CW state cools the planet and may prevent the onset of a runaway greenhouse state. At the outer edge, the resupply of water at low latitudes stabilizes the greenhouse effect and keeps the planet in the HD state and may prevent water from getting trapped at high latitudes in frozen form. Overall, the existence of bistability in the

THE DISCOVERY OF HD 37605c AND A DISPOSITIVE NULL DETECTION OF TRANSITS OF HD 37605b

International Nuclear Information System (INIS)

Wang, Sharon Xuesong; Wright, Jason T.; Mahadevan, Suvrath; Cochran, William; Endl, Michael; MacQueen, Phillip J.; Kane, Stephen R.; Von Braun, Kaspar; Henry, Gregory W.; Payne, Matthew J.; Ford, Eric B.; Valenti, Jeff A.; Antoci, Victoria; Dragomir, Diana; Matthews, Jaymie M.; Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard

2012-01-01

We report the radial velocity discovery of a second planetary mass companion to the K0 V star HD 37605, which was already known to host an eccentric, P ∼ 55 days Jovian planet, HD 37605b. This second planet, HD 37605c, has a period of ∼7.5 years with a low eccentricity and an Msin i of ∼3.4 M Jup . Our discovery was made with the nearly 8 years of radial velocity follow-up at the Hobby-Eberly Telescope and Keck Observatory, including observations made as part of the Transit Ephemeris Refinement and Monitoring Survey effort to provide precise ephemerides to long-period planets for transit follow-up. With a total of 137 radial velocity observations covering almost 8 years, we provide a good orbital solution of the HD 37605 system, and a precise transit ephemeris for HD 37605b. Our dynamic analysis reveals very minimal planet-planet interaction and an insignificant transit time variation. Using the predicted ephemeris, we performed a transit search for HD 37605b with the photometric data taken by the T12 0.8 m Automatic Photoelectric Telescope (APT) and the MOST satellite. Though the APT photometry did not capture the transit window, it characterized the stellar activity of HD 37605, which is consistent of it being an old, inactive star, with a tentative rotation period of 57.67 days. The MOST photometry enabled us to report a dispositive null detection of a non-grazing transit for this planet. Within the predicted transit window, we exclude an edge-on predicted depth of 1.9% at the >>10σ level, and exclude any transit with an impact parameter b > 0.951 at greater than 5σ. We present the BOOTTRAN package for calculating Keplerian orbital parameter uncertainties via bootstrapping. We made a comparison and found consistency between our orbital fit parameters calculated by the RVLIN package and error bars by BOOTTRAN with those produced by a Bayesian analysis using MCMC.

A Kinematical Detection of Two Embedded Jupiter-mass Planets in HD 163296

Science.gov (United States)

Teague, Richard; Bae, Jaehan; Bergin, Edwin A.; Birnstiel, Tilman; Foreman-Mackey, Daniel

2018-06-01

We present the first kinematical detection of embedded protoplanets within a protoplanetary disk. Using archival Atacama Large Millimetre Array (ALMA) observations of HD 163296, we demonstrate a new technique to measure the rotation curves of CO isotopologue emission to sub-percent precision relative to the Keplerian rotation. These rotation curves betray substantial deviations caused by local perturbations in the radial pressure gradient, likely driven by gaps carved in the gas surface density by Jupiter-mass planets. Comparison with hydrodynamic simulations shows excellent agreement with the gas rotation profile when the disk surface density is perturbed by two Jupiter-mass planets at 83 and 137 au. As the rotation of the gas is dependent upon the pressure of the total gas component, this method provides a unique probe of the gas surface density profile without incurring significant uncertainties due to gas-to-dust ratios or local chemical abundances that plague other methods. Future analyses combining both methods promise to provide the most accurate and robust measures of embedded planetary mass. Furthermore, this method provides a unique opportunity to explore wide-separation planets beyond the mm continuum edge and to trace the gas pressure profile essential in modeling grain evolution in disks.

Discovering transits of HD 209458-b type planets with Hipparcos and FAME photometry

Science.gov (United States)

Castellano, Timothy Paul

The motivation and prospects for success of a search for transits of short-period extrasolar planets of late-type main sequence stars in the Hipparcos satellite photometry archive is outlined. Recent extrasolar planet discoveries by the radial velocity (RV) method reveal that 1 in 20 spectral type F, G and K dwarfs possess short-period planets. Careful consideration of the transit detection probability as a function of stellar spectral type and planet orbit size results in the expectation that 6 to 24 transiting planets may be found among the 118,204 Hipparcos catalog stars. A search algorithm based on the known properties of the single known transiting extrasolar planet HD 209458-b was applied to carefully- selected samples of stars. The results of these searches and simulations of the detection efficiency for idealized transits are presented. Statistical and catalog-based methods for discriminating transits from intrinsic stellar variability and eclipses due to stellar companions are developed and described. Candidate lists that are the results of these searches are presented. Each candidate is placed in a color magnitude diagram based on Hipparcos derived distances and absolute magnitudes in order to clearly identify evolved stars. The effect of Lutz-Kelker bias on this main sequence membership determination is discussed in an Appendix. A Hipparcos-photometry-based intrinsic stellar variability determination is performed and compared to ground-based measurements. It is shown that intrinsic stellar variability of late-type main sequence stars is not a major concern for extrasolar jovian planet transit searches. The prospects for transit detection by the higher precision measurements of several hundred thousand main sequence stars to be made by the upcoming Full Sky Astrometric Explorer (FAME) satellite are similarly explored. A novel method for directly determining the mass of a transiting planet's parent star from timing measurements is introduced briefly in an

A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b

Science.gov (United States)

Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake

2007-01-01

We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

THE CALIFORNIA PLANET SURVEY. I. FOUR NEW GIANT EXOPLANETS

International Nuclear Information System (INIS)

Howard, Andrew W.; Marcy, Geoffrey W.; Peek, Kathryn M. G.; Johnson, John Asher; Fischer, Debra A.; Isaacson, Howard; Wright, Jason T.; Bernat, David; Henry, Gregory W.; Apps, Kevin; Endl, Michael; Cochran, William D.; Valenti, Jeff A.; Anderson, Jay; Piskunov, Nikolai E.

2010-01-01

We present precise Doppler measurements of four stars obtained during the past decade at Keck Observatory by the California Planet Survey (CPS). These stars, namely, HD 34445, HD 126614, HD 13931, and Gl 179, all show evidence for a single planet in Keplerian motion. We also present Doppler measurements from the Hobby-Eberly Telescope (HET) for two of the stars, HD 34445 and Gl 179, that confirm the Keck detections and significantly refine the orbital parameters. These planets add to the statistical properties of giant planets orbiting near or beyond the ice line, and merit follow-up by astrometry, imaging, and space-borne spectroscopy. Their orbital parameters span wide ranges of planetary minimum mass (M sin i = 0.38-1.9 M Jup ), orbital period (P = 2.87-11.5 yr), semimajor axis (a = 2.1-5.2 AU), and eccentricity (e = 0.02-0.41). HD 34445 b (P = 2.87 yr, M sin i = 0.79 M Jup , e = 0.27) is a massive planet orbiting an old, G-type star. We announce a planet, HD 126614 Ab, and an M dwarf, HD 126614 B, orbiting the metal-rich star HD 126614 (which we now refer to as HD 126614 A). The planet, HD 126614 Ab, has minimum mass M sin i = 0.38 M Jup and orbits the stellar primary with period P = 3.41 yr and orbital separation a = 2.3 AU. The faint M dwarf companion, HD 126614 B, is separated from the stellar primary by 489 mas (33 AU) and was discovered with direct observations using adaptive optics and the PHARO camera at Palomar Observatory. The stellar primary in this new system, HD 126614 A, has the highest measured metallicity ([Fe/H] = +0.56) of any known planet-bearing star. HD 13931 b (P = 11.5 yr, M sin i = 1.88 M Jup , e = 0.02) is a Jupiter analog orbiting a near solar twin. Gl 179 b (P = 6.3 yr, M sin i = 0.82 M Jup , e = 0.21) is a massive planet orbiting a faint M dwarf. The high metallicity of Gl 179 is consistent with the planet-metallicity correlation among M dwarfs, as documented recently by Johnson and Apps.

Thermal escape from extrasolar giant planets.

Science.gov (United States)

Koskinen, Tommi T; Lavvas, Panayotis; Harris, Matthew J; Yelle, Roger V

2014-04-28

The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b implies that these planets have hot and rapidly escaping atmospheres that extend to several planetary radii. These characteristics, however, cannot be generalized to all close-in EGPs. The thermal escape mechanism and mass loss rate from EGPs depend on a complex interplay between photochemistry and radiative transfer driven by the stellar UV radiation. In this study, we explore how these processes change under different levels of irradiation on giant planets with different characteristics. We confirm that there are two distinct regimes of thermal escape from EGPs, and that the transition between these regimes is relatively sharp. Our results have implications for thermal mass loss rates from different EGPs that we discuss in the context of currently known planets and the detectability of their upper atmospheres.

The Calan-Hertfordshire extrasolar planet search

Directory of Open Access Journals (Sweden)

Pinfield D.J.

2011-07-01

Full Text Available The detailed study of the exoplanetary systems HD189733 and HD209458 has given rise to a wealth of exciting information on the physics of exoplanetary atmospheres. To further our understanding of the make-up and processes within these atmospheres we require a larger sample of bright transiting planets. We have began a project to detect more bright transiting planets in the southern hemisphere by utilising precision radial-velocity measurements. We have observed a constrained sample of bright, inactive and metal-rich stars using the HARPS instrument and here we present the current status of this project, along with our first discoveries which include a brown dwarf/extreme-Jovian exoplanet found in the brown dwarf desert region around the star HD191760 and improved orbits for three other exoplanetary systems HD48265, HD143361 and HD154672. Finally, we briefly discuss the future of this project and the current prospects we have for discovering more bright transiting planets.

Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry

NARCIS (Netherlands)

Mulders, G.D.; Paardekooper, S.J.; Panic, O.; Dominik, C.; van Boekel, R.; Ratzka, T.

2013-01-01

Context. Giant planets form in protoplanetary disks while these disks are still gas-rich, and can reveal their presence through the annular gaps they carve out. HD 100546 is a gas-rich disk with a wide gap between a radius of ~1 and 13 AU, possibly cleared out by a planetary companion or planetary

LACK OF INFLATED RADII FOR KEPLER GIANT PLANET CANDIDATES RECEIVING MODEST STELLAR IRRADIATION

International Nuclear Information System (INIS)

Demory, Brice-Olivier; Seager, Sara

2011-01-01

The most irradiated transiting hot Jupiters are characterized by anomalously inflated radii, sometimes exceeding Jupiter's size by more than 60%. While different theoretical explanations have been applied, none of them provide a universal resolution to this observation, despite significant progress in the past years. We refine the photometric transit light curve analysis of 115 Kepler giant planet candidates based on public Q0-Q2 photometry. We find that 14% of them are likely false positives, based on their secondary eclipse depth. We report on planet radii versus stellar flux. We find an increase in planet radii with increased stellar irradiation for the Kepler giant planet candidates, in good agreement with existing hot Jupiter systems. We find that in the case of modest irradiation received from the stellar host, giant planets do not have inflated radii, and appear to have radii independent of the host star incident flux. This finding suggests that the physical mechanisms inflating hot Jupiters become ineffective below a given orbit-averaged stellar irradiation level of ∼2 × 10 8 erg s –1 cm –2 .

Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. V. A Massive Jupiter orbiting the very-low-metallicity giant star BD+03 2562 and a possible planet around HD 103485

Science.gov (United States)

Villaver, E.; Niedzielski, A.; Wolszczan, A.; Nowak, G.; Kowalik, K.; Adamów, M.; Maciejewski, G.; Deka-Szymankiewicz, B.; Maldonado, J.

2017-10-01

Context. Evolved stars with planets are crucial to understanding the dependency of the planet formation mechanism on the mass and metallicity of the parent star and to studying star-planet interactions. Aims: We present two evolved stars (HD 103485 and BD+03 2562) from the Tracking Advanced PlAnetary Systems (TAPAS) with HARPS-N project devoted to RV precision measurements of identified candidates within the PennState - Toruń Centre for Astronomy Planet Search. Methods: The paper is based on precise radial velocity (RV) measurements. For HD 103485 we collected 57 epochs over 3317 days with the Hobby-Eberly Telescope (HET) and its high-resolution spectrograph and 18 ultra-precise HARPS-N data over 919 days. For BD+03 2562 we collected 46 epochs of HET data over 3380 days and 19 epochs of HARPS-N data over 919 days. Results: We present the analysis of the data and the search for correlations between the RV signal and stellar activity, stellar rotation, and photometric variability. Based on the available data, we interpret the RV variations measured in both stars as Keplerian motion. Both stars have masses close to Solar (1.11 M⊙ HD 103485 and 1.14 M⊙ BD+03 2562), very low metallicities ([Fe/H] = - 0.50 and - 0.71 for HD 103485 and BD+03 2562), and both have Jupiter planetary mass companions (m2sini = 7 and 6.4 MJ for HD 103485 and BD+03 2562 resp.) in close to terrestrial orbits (1.4 au HD 103485 and 1.3 au BD+03 2562) with moderate eccentricities (e = 0.34 and 0.2 for HD 103485 and BD+03 2562). However, we cannot totally rule-out the possibility that the signal in the case of HD 103485 is due to rotational modulation of active regions. Conclusions: Based on the current data, we conclude that BD+03 2562 has a bona fide planetary companion while for HD 103485 we cannot totally exclude the possibility that the best explanation for the RV signal modulations is not the existence of a planet but stellar activity. If the interpretation remains that both stars have

The SOPHIE search for northern extrasolar planets. X. Detection and characterization of giant planets by the dozen

Science.gov (United States)

Hébrard, G.; Arnold, L.; Forveille, T.; Correia, A. C. M.; Laskar, J.; Bonfils, X.; Boisse, I.; Díaz, R. F.; Hagelberg, J.; Sahlmann, J.; Santos, N. C.; Astudillo-Defru, N.; Borgniet, S.; Bouchy, F.; Bourrier, V.; Courcol, B.; Delfosse, X.; Deleuil, M.; Demangeon, O.; Ehrenreich, D.; Gregorio, J.; Jovanovic, N.; Labrevoir, O.; Lagrange, A.-M.; Lovis, C.; Lozi, J.; Moutou, C.; Montagnier, G.; Pepe, F.; Rey, J.; Santerne, A.; Ségransan, D.; Udry, S.; Vanhuysse, M.; Vigan, A.; Wilson, P. A.

2016-04-01

We present new radial velocity measurements of eight stars that were secured with the spectrograph SOPHIE at the 193 cm telescope of the Haute-Provence Observatory. The measurements allow detecting and characterizing new giant extrasolar planets. The host stars are dwarfs of spectral types between F5 and K0 and magnitudes of between 6.7 and 9.6; the planets have minimum masses Mp sin I of between 0.4 to 3.8 MJup and orbitalperiods of several days to several months. The data allow only single planets to be discovered around the first six stars (HD 143105, HIP 109600, HD 35759, HIP 109384, HD 220842, and HD 12484), but one of them shows the signature of an additional substellar companion in the system. The seventh star, HIP 65407, allows the discovery of two giant planets that orbit just outside the 12:5 resonance in weak mutual interaction. The last star, HD 141399, was already known to host a four-planet system; our additional data and analyses allow new constraints to be set on it. We present Keplerian orbits of all systems, together with dynamical analyses of the two multi-planet systems. HD 143105 is one of the brightest stars known to host a hot Jupiter, which could allow numerous follow-up studies to be conducted even though this is not a transiting system. The giant planets HIP 109600b, HIP 109384b, and HD 141399c are located in the habitable zone of their host star. Based on observations collected with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France, by the SOPHIE Consortium (programs 07A.PNP.CONS to 15A.PNP.CONS).Full version of the SOPHIE measurements (Table 1) is 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/588/A145

Search for Exoplanets around Northern Circumpolar Stars. II. The Detection of Radial Velocity Variations in M Giant Stars HD 36384, HD 52030, and HD 208742

Energy Technology Data Exchange (ETDEWEB)

Lee, Byeong-Cheol; Jeong, Gwanghui; Han, Inwoo; Lee, Sang-Min; Kim, Kang-Min [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Park, Myeong-Gu; Oh, Hyeong-Il [Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Mkrtichian, David E. [National Astronomical Research Institute of Thailand, Chiang Mai 50200 (Thailand); Hatzes, Artie P. [Thüringer Landessternwarte Tautenburg (TLS), Sternwarte 5, D-07778 Tautenburg (Germany); Gu, Shenghong; Bai, Jinming, E-mail: bclee@kasi.re.kr [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

2017-07-20

We present the detection of long-period RV variations in HD 36384, HD 52030, and HD 208742 by using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) for the precise radial velocity (RV) survey of about 200 northern circumpolar stars. Analyses of RV data, chromospheric activity indicators, and bisector variations spanning about five years suggest that the RV variations are compatible with planet or brown dwarf companions in Keplerian motion. However, HD 36384 shows photometric variations with a period very close to that of RV variations as well as amplitude variations in the weighted wavelet Z-transform (WWZ) analysis, which argues that the RV variations in HD 36384 are from the stellar pulsations. Assuming that the companion hypothesis is correct, HD 52030 hosts a companion with minimum mass 13.3 M {sub Jup} orbiting in 484 days at a distance of 1.2 au. HD 208742 hosts a companion of 14.0 M {sub Jup} at 1.5 au with a period of 602 days. All stars are located at the asymptotic giant branch (AGB) stage on the H–R diagram after undergoing the helium flash and leaving the giant clump.With stellar radii of 53.0 R {sub ⊙} and 57.2 R {sub ⊙} for HD 52030 and HD 208742, respectively, these stars may be the largest yet, in terms of stellar radius, found to host substellar companions. However, given possible RV amplitude variations and the fact that these are highly evolved stars, the planet hypothesis is not yet certain.

Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

International Nuclear Information System (INIS)

McCullough, P. R.; Crouzet, N.; Deming, D.; Madhusudhan, N.

2014-01-01

We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s –1 . When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.

Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

Energy Technology Data Exchange (ETDEWEB)

McCullough, P. R.; Crouzet, N. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, N., E-mail: pmcc@stsci.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States)

2014-08-10

We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s{sup –1}. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.

Transit confirmation and improved stellar and planet parameters for the super-Earth HD 97658 b and its host star

Energy Technology Data Exchange (ETDEWEB)

Van Grootel, V.; Gillon, M.; Scuflaire, R. [Institut d' Astrophysique et de Géophysique, Université de Liège, 17 Allée du 6 Août, B-4000 Liège (Belgium); Valencia, D. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto, ON, M1C 1A4 (Canada); Madhusudhan, N.; Demory, B.-O.; Queloz, D. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Dragomir, D. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr. Suite 102, Goleta, CA 93117 (United States); Howe, A. R.; Burrows, A. S. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Deming, D. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Ehrenreich, D.; Lovis, C.; Mayor, M.; Pepe, F.; Segransan, D.; Udry, S. [Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, CH-1290 Sauverny (Switzerland); Seager, S., E-mail: valerie.vangrootel@ulg.ac.be [Department of Earth, Atmospheric and Planetary Sciences, Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

2014-05-01

Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present here the confirmation, based on Spitzer transit observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass (M {sub *} = 0.77 ± 0.05 M {sub ☉}) K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck-High Resolution Echelle Spectrometer (Keck-HIRES) radial velocities and Microvariability and Oscillations of STars (MOST) and Spitzer photometry. HD 97658 b is a massive (M{sub P}=7.55{sub −0.79}{sup +0.83} M{sub ⊕}) and large (R{sub P}=2.247{sub −0.095}{sup +0.098}R{sub ⊕} at 4.5 μm) super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, of at least 60% by mass, and very little H-He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age. Orbiting a bright host star, HD 97658 b will be a key target for upcoming space missions such as the Transiting Exoplanet Survey Satellite (TESS), the Characterizing Exoplanet Satellite (CHEOPS), the Planetary Transits and Oscillations of stars (PLATO), and the James Webb Space Telescope to characterize thoroughly its structure and atmosphere.

The 4.5 μm full-orbit phase curve of the hot Jupiter HD 209458b

International Nuclear Information System (INIS)

Zellem, Robert T.; Griffith, Caitlin A.; Showman, Adam P.; Lewis, Nikole K.; Knutson, Heather A.; Fortney, Jonathan J.; Laughlin, Gregory; Cowan, Nicolas B.; Agol, Eric; Burrows, Adam; Charbonneau, David; Deming, Drake; Langton, Jonathan

2014-01-01

The hot Jupiter HD 209458b is particularly amenable to detailed study as it is among the brightest transiting exoplanet systems currently known (V-mag = 7.65; K-mag = 6.308) and has a large planet-to-star contrast ratio. HD 209458b is predicted to be in synchronous rotation about its host star with a hot spot that is shifted eastward of the substellar point by superrotating equatorial winds. Here we present the first full-orbit observations of HD 209458b, in which its 4.5 μm emission was recorded with Spitzer/IRAC. Our study revises the previous 4.5 μm measurement of HD 209458b's secondary eclipse emission downward by ∼35% to 0.1391% −0.0069% +0.0072% , changing our interpretation of the properties of its dayside atmosphere. We find that the hot spot on the planet's dayside is shifted eastward of the substellar point by 40.°9 ± 6.°0, in agreement with circulation models predicting equatorial superrotation. HD 209458b's dayside (T bright = 1499 ± 15 K) and nightside (T bright = 972 ± 44 K) emission indicate a day-to-night brightness temperature contrast smaller than that observed for more highly irradiated exoplanets, suggesting that the day-to-night temperature contrast may be partially a function of the incident stellar radiation. The observed phase curve shape deviates modestly from global circulation model predictions potentially due to disequilibrium chemistry or deficiencies in the current hot CH 4 line lists used in these models. Observations of the phase curve at additional wavelengths are needed in order to determine the possible presence and spatial extent of a dayside temperature inversion, as well as to improve our overall understanding of this planet's atmospheric circulation.

The 4.5 μm full-orbit phase curve of the hot Jupiter HD 209458b

Energy Technology Data Exchange (ETDEWEB)

Zellem, Robert T.; Griffith, Caitlin A.; Showman, Adam P. [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Lewis, Nikole K. [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Knutson, Heather A. [Division of Geological and Planetary Sciences, MC 170-25 1200 East California Boulevard, Pasadena, CA 91125 (United States); Fortney, Jonathan J.; Laughlin, Gregory [Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Cowan, Nicolas B. [Department of Earth and Planetary Sciences, Northwestern University, Technological Institute, 2145 Sheridan Road, Evanston, IL 60208 (United States); Agol, Eric [Astronomy Department, University of Washington, Physics-Astronomy Building, 3910 15th Avenue NE, Seattle, WA 98195 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-16, Cambridge, MA 02138 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Langton, Jonathan, E-mail: rzellem@lpl.arizona.edu [Physics Department, Principia College, 1 Maybeck Place, Elsah, IL 62028 (United States)

2014-07-20

The hot Jupiter HD 209458b is particularly amenable to detailed study as it is among the brightest transiting exoplanet systems currently known (V-mag = 7.65; K-mag = 6.308) and has a large planet-to-star contrast ratio. HD 209458b is predicted to be in synchronous rotation about its host star with a hot spot that is shifted eastward of the substellar point by superrotating equatorial winds. Here we present the first full-orbit observations of HD 209458b, in which its 4.5 μm emission was recorded with Spitzer/IRAC. Our study revises the previous 4.5 μm measurement of HD 209458b's secondary eclipse emission downward by ∼35% to 0.1391%{sub −0.0069%}{sup +0.0072%}, changing our interpretation of the properties of its dayside atmosphere. We find that the hot spot on the planet's dayside is shifted eastward of the substellar point by 40.°9 ± 6.°0, in agreement with circulation models predicting equatorial superrotation. HD 209458b's dayside (T{sub bright} = 1499 ± 15 K) and nightside (T{sub bright} = 972 ± 44 K) emission indicate a day-to-night brightness temperature contrast smaller than that observed for more highly irradiated exoplanets, suggesting that the day-to-night temperature contrast may be partially a function of the incident stellar radiation. The observed phase curve shape deviates modestly from global circulation model predictions potentially due to disequilibrium chemistry or deficiencies in the current hot CH{sub 4} line lists used in these models. Observations of the phase curve at additional wavelengths are needed in order to determine the possible presence and spatial extent of a dayside temperature inversion, as well as to improve our overall understanding of this planet's atmospheric circulation.

FIRST SCATTERED-LIGHT IMAGE OF THE DEBRIS DISK AROUND HD 131835 WITH THE GEMINI PLANET IMAGER

Energy Technology Data Exchange (ETDEWEB)

Hung, Li-Wei; Arriaga, Pauline; Fitzgerald, Michael P.; Esposito, Thomas M. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Duchêne, Gaspard; Kalas, Paul G.; De Rosa, Robert J.; Graham, James R. [Astronomy Department, University of California, Berkeley CA 94720-3411 (United States); Maire, Jérôme; Chilcote, Jeffrey K. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Marois, Christian [National Research Council of Canada Herzberg, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Millar-Blanchaer, Maxwell A. [Department of Astronomy and Astrophysics, University of Toronto, Toronto ON M5S 3H4 (Canada); Bruzzone, Sebastian [Department of Physics and Astronomy, Centre for Planetary and Space Exploration, University of Western Ontario, London, ON N6A 3K7 (Canada); Rajan, Abhijith [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States); Pueyo, Laurent; Wolff, Schuyler G.; Chen, Christine H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Konopacky, Quinn [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Ammons, S. Mark [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94040 (United States); Draper, Zachary H. [University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada); and others

2015-12-10

We present the first scattered-light image of the debris disk around HD 131835 in the H band using the Gemini Planet Imager. HD 131835 is a ∼15 Myr old A2IV star at a distance of ∼120 pc in the Sco-Cen OB association. We detect the disk only in polarized light and place an upper limit on the peak total intensity. No point sources resembling exoplanets were identified. Compared to its mid-infrared thermal emission,  in scattered light the disk shows similar orientation but different morphology. The scattered-light disk extends from ∼75 to ∼210 AU in the disk plane with roughly flat surface density. Our Monte Carlo radiative transfer model can describe the observations with a model disk composed of a mixture of silicates and amorphous carbon. In addition to the obvious brightness asymmetry due to stronger forward scattering, we discover a weak brightness asymmetry along the major axis, with the northeast side being 1.3 times brighter than the southwest side at a 3σ level.

An Optical/Near-infrared Investigation of HD 100546 b with the Gemini Planet Imager and MagAO

Science.gov (United States)

Rameau, Julien; Follette, Katherine B.; Pueyo, Laurent; Marois, Christian; Macintosh, Bruce; Millar-Blanchaer, Maxwell; Wang, Jason J.; Vega, David; Doyon, René; Lafrenière, David; Nielsen, Eric L.; Bailey, Vanessa; Chilcote, Jeffrey K.; Close, Laird M.; Esposito, Thomas M.; Males, Jared R.; Metchev, Stanimir; Morzinski, Katie M.; Ruffio, Jean-Baptiste; Wolff, Schuyler G.; Ammons, S. M.; Barman, Travis S.; Bulger, Joanna; Cotten, Tara; De Rosa, Robert J.; Duchene, Gaspard; Fitzgerald, Michael P.; Goodsell, Stephen; Graham, James R.; Greenbaum, Alexandra Z.; Hibon, Pascale; Hung, Li-Wei; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Oppenheimer, Rebecca; Palmer, David; Patience, Jennifer; Perrin, Marshall D.; Poyneer, Lisa; Rajan, Abhijith; Rantakyrö, Fredrik T.; Marley, Mark S.; Savransky, Dmitry; Schneider, Adam C.; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Remi; Thomas, Sandrine; Wallace, J. Kent; Ward-Duong, Kimberly; Wiktorowicz, Sloane

2017-06-01

We present H band spectroscopic and Hα photometric observations of HD 100546 obtained with the Gemini Planet Imager and the Magellan Visible AO camera. We detect H band emission at the location of the protoplanet HD 100546 b, but show that the choice of data processing parameters strongly affects the morphology of this source. It appears point-like in some aggressive reductions, but rejoins an extended disk structure in the majority of the others. Furthermore, we demonstrate that this emission appears stationary on a timescale of 4.6 years, inconsistent at the 2σ level with a Keplerian clockwise orbit at 59 au in the disk plane. The H band spectrum of the emission is inconsistent with any type of low effective temperature object or accreting protoplanetary disk. It strongly suggests a scattered-light origin, as this is consistent with the spectrum of the star and the spectra extracted at other locations in the disk. A non-detection at the 5σ level of HD 100546 b in differential Hα imaging places an upper limit, assuming the protoplanet lies in a gap free of extinction, on the accretion luminosity of 1.7 × 10-4 L ⊙ and M\\dot{M}planetary photosphere or an accreting circumplanetary disk but is a disk feature enhanced by the point-spread function subtraction process. This non-detection is consistent with the non-detection in the K band reported in an earlier study but does not exclude the possibility that HD 100546 b is deeply embedded.

THE NASA-UC ETA-EARTH PROGRAM. I. A SUPER-EARTH ORBITING HD 7924

International Nuclear Information System (INIS)

Howard, Andrew W.; Marcy, Geoffrey W.; Johnson, John Asher; Fischer, Debra A.; Giguere, Matthew J.; Isaacson, Howard; Wright, Jason T.; Henry, Gregory W.; Valenti, Jeff A.; Anderson, Jay; Piskunov, Nikolai E.

2009-01-01

We report the discovery of the first low-mass planet to emerge from the NASA-UC Eta-Earth Program, a super-Earth orbiting the K0 dwarf HD 7924. Keplerian modeling of precise Doppler radial velocities reveals a planet with minimum mass M P sin i = 9.26 M + in a P = 5.398 d orbit. Based on Keck-HIRES measurements from 2001 to 2008, the planet is robustly detected with an estimated false alarm probability of less than 0.001. Photometric observations using the Automated Photometric Telescopes at Fairborn Observatory show that HD 7924 is photometrically constant over the radial velocity period to 0.19 mmag, supporting the existence of the planetary companion. No transits were detected down to a photometric limit of ∼0.5 mmag, eliminating transiting planets with a variety of compositions. HD 7924b is one of only eight planets detected by the radial velocity technique with M P sin i + and as such is a member of an emerging family of low-mass planets that together constrain theories of planet formation.

Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. VI. HD 238914 and TYC 3318-01333-1: two more Li-rich giants with planets

Science.gov (United States)

Adamów, M.; Niedzielski, A.; Kowalik, K.; Villaver, E.; Wolszczan, A.; Maciejewski, G.; Gromadzki, M.

2018-05-01

Context. We present the latest results of our search for planets with HARPS-N at the 3.6 m Telescopio Nazionale Galileo under the Tracking Advanced Planetary Systems project: an in-depth study of the 15 most Li abundant giants from the PennState - Toruń Planet Search sample. Aims: Our goals are first, to obtain radial velocities of the most Li-rich giants we identified in our sample to search for possible low-mass substellar companions, and second, to perform an extended spectral analysis to define the evolutionary status of these stars. Methods: This work is based on high-resolution spectra obtained with the Hobby-Eberly Telescope and its High Resolution Spectrograph, and with the HARPS-N spectrograph at the Telescopio Nazionale Galileo. Two stars, HD 181368 and HD 188214, were also observed with UVES at the VLT to determine beryllium abundances. Results: We report i) the discovery of two new planetary systems around the Li-rich giant stars: HD 238914 and TYC 3318-01333-1 (a binary system); ii) reveal a binary Li-rich giant, HD 181368; iii) although our current phase coverage is not complete, we suggest the presence of planetary mass companions around TYC 3663-01966-1 and TYC 3105-00152-1; iv) we confirm the previous result for BD+48 740 and present updated orbital parameters, and v) we find a lack of a relation between the Li enhancement and the Be abundance for the stars HD 181368 and HD 188214, for which we acquired blue spectra. Conclusions: We found seven stars with stellar or potential planetary companions among the 15 Li-rich giant stars. The binary star frequency of the Li-rich giants in our sample appears to be normal, but the planet frequency is twice that of the general sample, which suggests a possible connection between hosting a companion and enhanced Li abundance in giant stars. We also found most of the companions orbits to be highly eccentric. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the

THE COMPOSITIONAL DIVERSITY OF EXTRASOLAR TERRESTRIAL PLANETS. II. MIGRATION SIMULATIONS

International Nuclear Information System (INIS)

Carter-Bond, Jade C.; O'Brien, David P.; Raymond, Sean N.

2012-01-01

Prior work has found that a variety of terrestrial planetary compositions are expected to occur within known extrasolar planetary systems. However, such studies ignored the effects of giant planet migration, which is thought to be very common in extrasolar systems. Here we present calculations of the compositions of terrestrial planets that formed in dynamical simulations incorporating varying degrees of giant planet migration. We used chemical equilibrium models of the solid material present in the disks of five known planetary host stars: the Sun, GJ 777, HD4203, HD19994, and HD213240. Giant planet migration has a strong effect on the compositions of simulated terrestrial planets as the migration results in large-scale mixing between terrestrial planet building blocks that condensed at a range of temperatures. This mixing acts to (1) increase the typical abundance of Mg-rich silicates in the terrestrial planets' feeding zones and thus increase the frequency of planets with Earth-like compositions compared with simulations with static giant planet orbits, and (2) drastically increase the efficiency of the delivery of hydrous phases (water and serpentine) to terrestrial planets and thus produce waterworlds and/or wet Earths. Our results demonstrate that although a wide variety of terrestrial planet compositions can still be produced, planets with Earth-like compositions should be common within extrasolar planetary systems.

Rapid heating of the atmosphere of an extrasolar planet.

Science.gov (United States)

Laughlin, Gregory; Deming, Drake; Langton, Jonathan; Kasen, Daniel; Vogt, Steve; Butler, Paul; Rivera, Eugenio; Meschiari, Stefano

2009-01-29

Near-infrared observations of more than a dozen 'hot-Jupiter' extrasolar planets have now been reported. These planets display a wide diversity of properties, yet all are believed to have had their spin periods tidally spin-synchronized with their orbital periods, resulting in permanent star-facing hemispheres and surface flow patterns that are most likely in equilibrium. Planets in significantly eccentric orbits can enable direct measurements of global heating that are largely independent of the details of the hydrodynamic flow. Here we report 8-microm photometric observations of the planet HD 80606b during a 30-hour interval bracketing the periastron passage of its extremely eccentric 111.4-day orbit. As the planet received its strongest irradiation (828 times larger than the flux received at apastron) its maximum 8-microm brightness temperature increased from approximately 800 K to approximately 1,500 K over a six-hour period. We also detected a secondary eclipse for the planet, which implies an orbital inclination of i approximately 90 degrees , fixes the planetary mass at four times the mass of Jupiter, and constrains the planet's tidal luminosity. Our measurement of the global heating rate indicates that the radiative time constant at the planet's 8-microm photosphere is approximately 4.5 h, in comparison with 3-5 days in Earth's stratosphere.

Very Low-mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. VI. A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646

Science.gov (United States)

Ma, Bo; Ge, Jian; Wolszczan, Alex; Muterspaugh, Matthew W.; Lee, Brian; Henry, Gregory W.; Schneider, Donald P.; Martín, Eduardo L.; Niedzielski, Andrzej; Xie, Jiwei; Fleming, Scott W.; Thomas, Neil; Williamson, Michael; Zhu, Zhaohuan; Agol, Eric; Bizyaev, Dmitry; Nicolaci da Costa, Luiz; Jiang, Peng; Martinez Fiorenzano, A. F.; González Hernández, Jonay I.; Guo, Pengcheng; Grieves, Nolan; Li, Rui; Liu, Jane; Mahadevan, Suvrath; Mazeh, Tsevi; Nguyen, Duy Cuong; Paegert, Martin; Sithajan, Sirinrat; Stassun, Keivan; Thirupathi, Sivarani; van Eyken, Julian C.; Wan, Xiaoke; Wang, Ji; Wisniewski, John P.; Zhao, Bo; Zucker, Shay

2016-11-01

We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the “Classic” spectrograph at the Automatic Spectroscopic Telescope at the Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period BD in this binary. HD 87646 is a close binary with a separation of ˜22 au between the two stars, estimated using the Hipparcos catalog and our newly acquired AO image from PALAO on the 200 inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has {T}{eff} = 5770 ± 80 K, log g = 4.1 ± 0.1, and [Fe/H] = -0.17 ± 0.08. The derived minimum masses of the two substellar companions of HD 87646A are 12.4 ± 0.7 {M}{Jup} and 57.0 ± 3.7 {M}{Jup}. The periods are 13.481 ± 0.001 days and 674 ± 4 days and the measured eccentricities are 0.05 ± 0.02 and 0.50 ± 0.02 respectively. Our dynamical simulations show that the system is stable if the binary orbit has a large semimajor axis and a low eccentricity, which can be verified with future astrometry observations.

Three Super-Earths Orbiting HD 7924

Science.gov (United States)

Fulton, Benjamin J.; Weiss, Lauren M.; Sinukoff, Evan; Isaacson, Howard; Howard, Andrew W.; Marcy, Geoffrey W.; Henry, Gregory W.; Holden, Bradford P.; Kibrick, Robert I.

2015-06-01

We report the discovery of two super-Earth-mass planets orbiting the nearby K0.5 dwarf HD 7924, which was previously known to host one small planet. The new companions have masses of 7.9 and 6.4 {{M}\\oplus }, and orbital periods of 15.3 and 24.5 days. We perform a joint analysis of high-precision radial velocity data from Keck/HIRES and the new Automated Planet Finder Telescope (APF) to robustly detect three total planets in the system. We refine the ephemeris of the previously known planet using 5 yr of new Keck data and high-cadence observations over the last 1.3 yr with the APF. With this new ephemeris, we show that a previous transit search for the inner-most planet would have covered 70% of the predicted ingress or egress times. Photometric data collected over the last eight years using the Automated Photometric Telescope shows no evidence for transits of any of the planets, which would be detectable if the planets transit and their compositions are hydrogen-dominated. We detect a long-period signal that we interpret as the stellar magnetic activity cycle since it is strongly correlated with the Ca ii H and K activity index. We also detect two additional short-period signals that we attribute to rotationally modulated starspots and a one-month alias. The high-cadence APF data help to distinguish between the true orbital periods and aliases caused by the window function of the Keck data. The planets orbiting HD 7924 are a local example of the compact, multi-planet systems that the Kepler Mission found in great abundance. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of Hawai‘i, the University of California, and NASA.

ON THE VALIDITY OF THE 'HILL RADIUS CRITERION' FOR THE EJECTION OF PLANETS FROM STELLAR HABITABLE ZONES

International Nuclear Information System (INIS)

Cuntz, M.; Yeager, K. E.

2009-01-01

We challenge the customary assumption that the entering of an Earth-mass planet into the Hill radius (or multiples of the Hill radius) of a giant planet is a valid criterion for its ejection from the star-planet system. This assumption has widely been used in previous studies, especially those with an astrobiological focus. As intriguing examples, we explore the dynamics of the systems HD 20782 and HD 188015. Each system possesses a giant planet that remains in or crosses into the stellar habitable zone, thus effectively thwarting the possibility of habitable terrestrial planets. In the case of HD 188015, the orbit of the giant planet is almost circular, whereas in the case of HD 20782, it is extremely elliptical. Although it is found that Earth-mass planets are eventually ejected from the habitable zones of these systems, the 'Hill Radius Criterion' is identified as invalid for the prediction of when the ejection is actually occurring.

Stellar photospheric abundances as a probe of discs and planets

Science.gov (United States)

Jermyn, Adam S.; Kama, Mihkel

2018-06-01

Protoplanetary discs, debris discs, and disrupted or evaporating planets can all feed accretion on to stars. The photospheric abundances of such stars may then reveal the composition of the accreted material. This is especially likely in B to mid-F type stars, which have radiative envelopes and hence less bulk-photosphere mixing. We present a theoretical framework (CAM), considering diffusion, rotation, and other stellar mixing mechanisms to describe how the accreted material interacts with the bulk of the star. This allows the abundance pattern of the circumstellar material to be calculated from measured stellar abundances and parameters (vrot, Teff). We discuss the λ Boötis phenomenon and the application of CAM on stars hosting protoplanetary discs (HD 100546, HD 163296), debris discs (HD 141569, HD 21997), and evaporating planets (HD 195689/KELT-9).

THE PAN-PACIFIC PLANET SEARCH. II. CONFIRMATION OF A TWO-PLANET SYSTEM AROUND HD 121056

Energy Technology Data Exchange (ETDEWEB)

Wittenmyer, Robert A.; Tinney, C. G. [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Wang, Liang [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China); Liu, Fan [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Horner, Jonathan [Australian Centre for Astrobiology, University of New South Wales, Sydney, NSW 2052 (Australia); Endl, Michael [McDonald Observatory, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States); Johnson, John Asher [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Carter, B. D., E-mail: rob@unsw.edu.au [Computational Engineering and Science Research Centre, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia)

2015-02-10

Precise radial velocities from the Anglo-Australian Telescope (AAT) confirm the presence of a rare short-period planet around the K0 giant HD 121056. An independent two-planet solution using the AAT data shows that the inner planet has P = 89.1 ± 0.1 days, and m sin i = 1.35 ± 0.17 M{sub Jup}. These data also confirm the planetary nature of the outer companion, with m sin i = 3.9 ± 0.6 M{sub Jup} and a = 2.96 ± 0.16 AU. HD 121056 is the most-evolved star to host a confirmed multiple-planet system, and is a valuable example of a giant star hosting both a short-period and a long-period planet.

THE PAN-PACIFIC PLANET SEARCH. II. CONFIRMATION OF A TWO-PLANET SYSTEM AROUND HD 121056

International Nuclear Information System (INIS)

Wittenmyer, Robert A.; Tinney, C. G.; Wang, Liang; Liu, Fan; Horner, Jonathan; Endl, Michael; Johnson, John Asher; Carter, B. D.

2015-01-01

Precise radial velocities from the Anglo-Australian Telescope (AAT) confirm the presence of a rare short-period planet around the K0 giant HD 121056. An independent two-planet solution using the AAT data shows that the inner planet has P = 89.1 ± 0.1 days, and m sin i = 1.35 ± 0.17 M Jup . These data also confirm the planetary nature of the outer companion, with m sin i = 3.9 ± 0.6 M Jup and a = 2.96 ± 0.16 AU. HD 121056 is the most-evolved star to host a confirmed multiple-planet system, and is a valuable example of a giant star hosting both a short-period and a long-period planet

First Light from Extrasolar Planets and Implications for Astrobiology

Science.gov (United States)

Richardson, L. Jeremy; Seager, Sara; Harrington, Joseph; Deming, Drake

2005-01-01

The first light from an extrasolar planet was recently detected. These results, obtained for two transiting extrasolar planets at different infrared wavelengths, open a new era in the field of extrasolar planet detection and characterization because for the first time we can now detect planets beyond the solar system directly. Using the Spitzer Space Telescope at 24 microns, we observed the modulation of combined light (star plus planet) from the HD 209458 system as the planet disappeared behind the star during secondary eclipse and later re-emerged, thereby isolating the light from the planet. We obtained a planet-to-star ratio of 0.26% at 24 microns, corresponding to a brightness temperature of 1130 + / - 150 K. We will describe this result in detail, explain what it can tell us about the atmosphere of HD 209458 b, and discuss implications for the field of astrobiology. These results represent a significant step on the path to detecting terrestrial planets around other stars and in understanding their atmospheres in terms of composition and temperature.

THE REFLECTION EFFECT IN INTERACTING BINARIES OR IN PLANET-STAR SYSTEMS

International Nuclear Information System (INIS)

Budaj, J.

2011-01-01

There are many similarities between interacting binary stars and stars with a close-in giant extrasolar planet. The reflection effect is a well-known example. Although the generally accepted treatment of this effect in interacting binaries is successful in fitting light curves of eclipsing binaries, it is not very suitable for studying cold objects irradiated by hot objects or extrasolar planets. The aim of this paper is to develop a model of the reflection effect which could be easily incorporated into the present codes for modeling of interacting binaries so that these can be used to study the aforementioned objects. Our model of the reflection effect takes into account the reflection (scattering), heating, and heat redistribution over the surface of the irradiated object. The shape of the object is described by the non-spherical Roche potential expected for close objects. Limb and gravity darkening are included in the calculations of the light output from the system. The model also accounts for the orbital revolution and rotation of the exoplanet with appropriate Doppler shifts for the scattered and thermal radiation. Subsequently, light curves and/or spectra of several exoplanets have been modeled and the effects of the heat redistribution, limb darkening/brightening, (non-)gray albedo, and non-spherical shape have been studied. Recent observations of planet-to-star flux ratio of HD189733b, WASP12b, and WASP-19b at various phases were reproduced with very good accuracy. It was found that HD189733b has a low Bond albedo and intense heat redistribution, while WASP-19b has a low Bond albedo and low heat redistribution. The exact Roche geometries and temperature distributions over the surface of all 78 transiting extrasolar planets have been determined. Departures from the spherical shape may vary considerably but departures of about 1% in the radius are common within the sample. In some cases, these departures can reach 8%, 12%, or 14%, for WASP-33b, WASP-19b, and

THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION MODELS OF HD 189733b AND HD 209458b WITH CONSISTENT MAGNETIC DRAG AND OHMIC DISSIPATION

International Nuclear Information System (INIS)

Rauscher, Emily; Menou, Kristen

2013-01-01

We present the first three-dimensional circulation models for extrasolar gas giant atmospheres with geometrically and energetically consistent treatments of magnetic drag and ohmic dissipation. Atmospheric resistivities are continuously updated and calculated directly from the flow structure, strongly coupling the magnetic effects with the circulation pattern. We model the hot Jupiters HD 189733b (T eq ≈ 1200 K) and HD 209458b (T eq ≈ 1500 K) and test planetary magnetic field strengths from 0 to 30 G. We find that even at B = 3 G the atmospheric structure and circulation of HD 209458b are strongly influenced by magnetic effects, while the cooler HD 189733b remains largely unaffected, even in the case of B = 30 G and super-solar metallicities. Our models of HD 209458b indicate that magnetic effects can substantially slow down atmospheric winds, change circulation and temperature patterns, and alter observable properties. These models establish that longitudinal and latitudinal hot spot offsets, day-night flux contrasts, and planetary radius inflation are interrelated diagnostics of the magnetic induction process occurring in the atmospheres of hot Jupiters and other similarly forced exoplanets. Most of the ohmic heating occurs high in the atmosphere and on the dayside of the planet, while the heating at depth is strongly dependent on the internal heat flux assumed for the planet, with more heating when the deep atmosphere is hot. We compare the ohmic power at depth in our models, and estimates of the ohmic dissipation in the bulk interior (from general scaling laws), to evolutionary models that constrain the amount of heating necessary to explain the inflated radius of HD 209458b. Our results suggest that deep ohmic heating can successfully inflate the radius of HD 209458b for planetary magnetic field strengths of B ≥ 3-10 G.

3.6 AND 4.5 μm PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b

International Nuclear Information System (INIS)

Knutson, Heather A.; Lewis, Nikole; Showman, Adam P.; Fortney, Jonathan J.; Laughlin, Gregory; Burrows, Adam; Cowan, Nicolas B.; Agol, Eric; Aigrain, Suzanne; Charbonneau, David; Désert, Jean-Michel; Deming, Drake; Henry, Gregory W.; Langton, Jonathan

2012-01-01

We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 μm bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 μm, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters and uncertainties using a wavelet-based Markov Chain Monte Carlo analysis that accounts for the presence of time-correlated noise in our data. We measure a phase curve amplitude of 0.1242% ± 0.0061% in the 3.6 μm band and 0.0982% ± 0.0089% in the 4.5 μm band, corresponding to brightness temperature contrasts of 503 ± 21 K and 264 ± 24 K, respectively. We find that the times of minimum and maximum flux occur several hours earlier than predicted for an atmosphere in radiative equilibrium, consistent with the eastward advection of gas by an equatorial super-rotating jet. The locations of the flux minima in our new data differ from our previous observations at 8 μm, and we present new evidence indicating that the flux minimum observed in the 8 μm is likely caused by an overshooting effect in the 8 μm array. We obtain improved estimates for HD 189733b's dayside planet-star flux ratio of 0.1466% ± 0.0040% in the 3.6 μm band and 0.1787% ± 0.0038% in the 4.5 μm band, corresponding to brightness temperatures of 1328 ± 11 K and 1192 ± 9 K, respectively; these are the most accurate secondary eclipse depths obtained to date for an extrasolar planet. We compare our new dayside and nightside spectra for HD 189733b to the predictions of one-dimensional radiative transfer models from Burrows et al. and conclude that fits to

3.6 AND 4.5 {mu}m PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b

Energy Technology Data Exchange (ETDEWEB)

Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Lewis, Nikole; Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Fortney, Jonathan J.; Laughlin, Gregory [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Cowan, Nicolas B. [CIERA, Northwestern University, Evanston, IL 60208 (United States); Agol, Eric [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Aigrain, Suzanne [Sub-department of Astrophysics, Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Charbonneau, David; Desert, Jean-Michel [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Langton, Jonathan, E-mail: hknutson@caltech.edu [Department of Physics, Principia College, 1 Maybeck Place, Elsah, IL 62028 (United States)

2012-07-20

We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 {mu}m bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 {mu}m, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters and uncertainties using a wavelet-based Markov Chain Monte Carlo analysis that accounts for the presence of time-correlated noise in our data. We measure a phase curve amplitude of 0.1242% {+-} 0.0061% in the 3.6 {mu}m band and 0.0982% {+-} 0.0089% in the 4.5 {mu}m band, corresponding to brightness temperature contrasts of 503 {+-} 21 K and 264 {+-} 24 K, respectively. We find that the times of minimum and maximum flux occur several hours earlier than predicted for an atmosphere in radiative equilibrium, consistent with the eastward advection of gas by an equatorial super-rotating jet. The locations of the flux minima in our new data differ from our previous observations at 8 {mu}m, and we present new evidence indicating that the flux minimum observed in the 8 {mu}m is likely caused by an overshooting effect in the 8 {mu}m array. We obtain improved estimates for HD 189733b's dayside planet-star flux ratio of 0.1466% {+-} 0.0040% in the 3.6 {mu}m band and 0.1787% {+-} 0.0038% in the 4.5 {mu}m band, corresponding to brightness temperatures of 1328 {+-} 11 K and 1192 {+-} 9 K, respectively; these are the most accurate secondary eclipse depths obtained to date for an extrasolar planet. We compare our new dayside and nightside spectra for HD 189733b to the predictions of one-dimensional radiative transfer models

DEBRIS DISTRIBUTION IN HD 95086—A YOUNG ANALOG OF HR 8799

International Nuclear Information System (INIS)

Su, Kate Y. L.; Smith, Paul S.; Rieke, George H.; Morrison, Sarah; Malhotra, Renu; Balog, Zoltan

2015-01-01

HD 95086 is a young early-type star that hosts (1) a 5 M J planet at the projected distance of 56 AU revealed by direct imaging, and (2) a prominent debris disk. Here we report the detection of 69 μm crystalline olivine feature from the disk using the Spitzer/MIPS-SED data covering 55-95 μm. Due to the low resolution of the MIPS-SED mode, this feature is not spectrally resolved, but is consistent with the emission from crystalline forsterite contributing ∼5% of the total dust mass. We also present detailed analysis of the disk spectral energy distribution and re-analysis of resolved images obtained by Herschel. Our results suggest that the debris structure around HD 95086 consists of a warm (∼175 K) belt, a cold (∼55 K) disk, and an extended disk halo (up to ∼800 AU), and is very similar to that of HR 8799. We compare the properties of the three debris components, and suggest that HD 95086 is a young analog of HR 8799. We further investigate and constrain single-planet, two-planet, three-planet, and four-planet architectures that can account for the observed debris structure and are compatible with dynamical stability constraints. We find that equal-mass four-planet configurations of geometrically spaced orbits, with each planet of mass ∼ 5 M J , could maintain the gap between the warm and cold debris belts, and also be just marginally stable for timescales comparable to the age of the system

DEBRIS DISTRIBUTION IN HD 95086—A YOUNG ANALOG OF HR 8799

Energy Technology Data Exchange (ETDEWEB)

Su, Kate Y. L.; Smith, Paul S.; Rieke, George H. [Steward Observatory, University of Arizona, 933 N Cherry Ave., Tucson, AZ 85721 (United States); Morrison, Sarah; Malhotra, Renu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Balog, Zoltan, E-mail: ksu@as.arizona.edu [Max-Planck-Institut für Astronomie, Königstuhl 17 D-69117, Heidelberg (Germany)

2015-02-01

HD 95086 is a young early-type star that hosts (1) a 5 M{sub J} planet at the projected distance of 56 AU revealed by direct imaging, and (2) a prominent debris disk. Here we report the detection of 69 μm crystalline olivine feature from the disk using the Spitzer/MIPS-SED data covering 55-95 μm. Due to the low resolution of the MIPS-SED mode, this feature is not spectrally resolved, but is consistent with the emission from crystalline forsterite contributing ∼5% of the total dust mass. We also present detailed analysis of the disk spectral energy distribution and re-analysis of resolved images obtained by Herschel. Our results suggest that the debris structure around HD 95086 consists of a warm (∼175 K) belt, a cold (∼55 K) disk, and an extended disk halo (up to ∼800 AU), and is very similar to that of HR 8799. We compare the properties of the three debris components, and suggest that HD 95086 is a young analog of HR 8799. We further investigate and constrain single-planet, two-planet, three-planet, and four-planet architectures that can account for the observed debris structure and are compatible with dynamical stability constraints. We find that equal-mass four-planet configurations of geometrically spaced orbits, with each planet of mass ∼ 5 M{sub J} , could maintain the gap between the warm and cold debris belts, and also be just marginally stable for timescales comparable to the age of the system.

RESONANCES REQUIRED: DYNAMICAL ANALYSIS OF THE 24 Sex AND HD 200964 PLANETARY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G., E-mail: rob@phys.unsw.edu.au [Department of Astrophysics, School of Physics, Faculty of Science, University of New South Wales, NSW 2052 (Australia)

2012-12-20

We perform several suites of highly detailed dynamical simulations to investigate the architectures of the 24 Sextantis and HD 200964 planetary systems. The best-fit orbital solution for the two planets in the 24 Sex system places them on orbits with periods that lie very close to 2:1 commensurability, while that for the HD 200964 system places the two planets therein in orbits whose periods lie close to a 4:3 commensurability. In both cases, the proposed best-fit orbits are mutually crossing-a scenario that is only dynamically feasible if the planets are protected from close encounters by the effects of mutual mean-motion resonance (MMR). Our simulations reveal that the best-fit orbits for both systems lie within narrow islands of dynamical stability, and are surrounded by much larger regions of extreme instability. As such, we show that the planets are only feasible if they are currently trapped in mutual MMR-the 2:1 resonance in the case of 24 Sex b and c, and the 4:3 resonance in the case of HD 200964 b and c. In both cases, the region of stability is strongest and most pronounced when the planetary orbits are mutually coplanar. As the inclination of planet c with respect to planet b is increased, the stability of both systems rapidly collapses.

DISCOVERY AND ATMOSPHERIC CHARACTERIZATION OF GIANT PLANET KEPLER-12b: AN INFLATED RADIUS OUTLIER

International Nuclear Information System (INIS)

Fortney, Jonathan J.; Nutzman, Philip; Demory, Brice-Olivier; Désert, Jean-Michel; Buchhave, Lars A.; Charbonneau, David; Fressin, François; Rowe, Jason; Caldwell, Douglas A.; Jenkins, Jon M.; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew; Knutson, Heather A.; Ciardi, David; Gautier, Thomas N.; Batalha, Natalie M.; Bryson, Stephen T.; Howell, Steve B.; Everett, Mark

2011-01-01

We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 R J is among the handful of planets with super-inflated radii above 1.65 R J . Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 M J planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 ± 0.010 g cm –3 . We detect the occultation of the planet at a significance of 3.7σ in the Kepler bandpass. This yields a geometric albedo of 0.14 ± 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7σ and 4σ in the 3.6 and 4.5 μm bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1σ) and e < 0.09 (3σ). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.

Infrared radiation from an extrasolar planet

OpenAIRE

Deming, Drake; Seager, Sara; Richardson, L. Jeremy; Harrington, Joseph

2005-01-01

A class of extrasolar giant planets - the so-called `hot Jupiters' - orbit within 0.05 AU of their primary stars. These planets should be hot and so emit detectable infrared radiation. The planet HD 209458b is an ideal candidate for the detection and characterization of this infrared light because it is eclipsed by the star. This planet has an anomalously large radius (1.35 times that of Jupiter), which may be the result of ongoing tidal dissipation, but this explanation requires a non-zero o...

A SEARCH FOR THE TRANSIT OF HD 168443b: IMPROVED ORBITAL PARAMETERS AND PHOTOMETRY

Energy Technology Data Exchange (ETDEWEB)

Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T.; Wang, Xuesong X. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Kane, Stephen R.; Ciardi, David R.; Dragomir, Diana; Von Braun, Kaspar [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Howard, Andrew W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); De Pree, Chris; Marlowe, Hannah [Department of Physics and Astronomy, Agnes Scott College, 141 East College Avenue, Decatur, GA 30030 (United States); Fischer, Debra [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Laughlin, Gregory [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Rabus, Markus, E-mail: gcp5017@psu.edu, E-mail: suvrath@astro.psu.edu [Departamento de Astonomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

2011-12-20

The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. In this work we present the search for transits of HD 168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a priori transit probability beyond that expected for a circular orbit, making HD 168443 a candidate for our ongoing Transit Ephemeris Refinement and Monitoring Survey. Using additional radial velocities from Keck High Resolution Echelle Spectrometer, we refined the orbital parameters of this multi-planet system and derived a new transit ephemeris for HD 168443b. The reduced uncertainties in the transit window make a photometric transit search practicable. Photometric observations acquired during predicted transit windows were obtained on three nights. Cerro Tololo Inter-American Observatory 1.0 m photometry acquired on 2010 September 7 had the required precision to detect a transit but fell just outside of our final transit window. Nightly photometry from the T8 0.8 m automated photometric telescope at Fairborn Observatory, acquired over a span of 109 nights, demonstrates that HD 168443 is constant on a timescale of weeks. Higher-cadence photometry on 2011 April 28 and June 25 shows no evidence of a transit. We are able to rule out a non-grazing transit of HD 168443b.

A Search for the Transit of HD 168443b: Improved Orbital Parameters and Photometry

Science.gov (United States)

Pilyavsky, Genady; Mahadevan, Suvrath; Kane, Stephen R.; Howard, Andrew W.; Ciardi, David R.; de Pree, Chris; Dragomir, Diana; Fischer, Debra; Henry, Gregory W.; Jensen, Eric L. N.; Laughlin, Gregory; Marlowe, Hannah; Rabus, Markus; von Braun, Kaspar; Wright, Jason T.; Wang, Xuesong X.

2011-12-01

The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. In this work we present the search for transits of HD 168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a priori transit probability beyond that expected for a circular orbit, making HD 168443 a candidate for our ongoing Transit Ephemeris Refinement and Monitoring Survey. Using additional radial velocities from Keck High Resolution Echelle Spectrometer, we refined the orbital parameters of this multi-planet system and derived a new transit ephemeris for HD 168443b. The reduced uncertainties in the transit window make a photometric transit search practicable. Photometric observations acquired during predicted transit windows were obtained on three nights. Cerro Tololo Inter-American Observatory 1.0 m photometry acquired on 2010 September 7 had the required precision to detect a transit but fell just outside of our final transit window. Nightly photometry from the T8 0.8 m automated photometric telescope at Fairborn Observatory, acquired over a span of 109 nights, demonstrates that HD 168443 is constant on a timescale of weeks. Higher-cadence photometry on 2011 April 28 and June 25 shows no evidence of a transit. We are able to rule out a non-grazing transit of HD 168443b.

The Gemini Deep Planet Survey - GDPS

Energy Technology Data Exchange (ETDEWEB)

Lafreniere, D; Doyon, R; Marois, C; Nadeau, D; Oppenheimer, B R; Roche, P F; Rigaut, F; Graham, J R; Jayawardhana, R; Johnstone, D; Kalas, P G; Macintosh, B; Racine, R

2007-06-01

We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope and angular differential imaging was used to suppress the speckle noise of the central star. Detection limits for the 85 stars observed are presented, along with a list of all faint point sources detected around them. Typically, the observations are sensitive to angular separations beyond 0.5-inch with 5{sigma} contrast sensitivities in magnitude difference at 1.6 {micro}m of 9.6 at 0.5-inch, 12.9 at 1-inch, 15 at 2-inch, and 16.6 at 5-inch. For the typical target of the survey, a 100 Myr old K0 star located 22 pc from the Sun, the observations are sensitive enough to detect planets more massive than 2 M{sub Jup} with a projected separation in the range 40-200 AU. Depending on the age, spectral type, and distance of the target stars, the minimum mass that could be detected with our observations can be {approx}1 M{sub Jup}. Second epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results, which provide upper limits on the fractions of stars with giant planet or low mass brown dwarf companions, is presented. Assuming a planet mass distribution dn/dm {proportional_to} m{sup -1.2} and a semi-major axis distribution dn/da {proportional_to} a{sup -1}, the upper limits on the fraction of stars with at least one planet of mass 0.5-13 M{sub Jup} are 0.29 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.09 for 50-250 AU, with a 95% confidence level; this result is weakly dependent on the semi-major axis distribution power-law index. Without making any assumption on the mass and semi-major axis distributions, the fraction of stars with at least one brown dwarf companion having a semi-major axis in the

CHARACTERIZING THE RIGIDLY ROTATING MAGNETOSPHERE STARS HD 345439 AND HD 23478

Energy Technology Data Exchange (ETDEWEB)

Wisniewski, J. P.; Lomax, J. R. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Chojnowski, S. D. [Department of Astronomy, New Mexico State University, 1780 E University Avenue, Las Cruces, NM 88003 (United States); Davenport, J. R. A. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Bartz, J.; Pepper, J. [Lehigh University, Department of Physics, 413 Deming Lewis Lab, 16 Memorial Drive, East Bethlehem, PA 18015 (United States); Whelan, D. G. [Department of Physics, Austin College, 900 N. Grand Avenue, Sherman, TX 75090 (United States); Eikenberry, S. S. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Majewski, S. R.; Skrutskie, M. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Richardson, N. D., E-mail: wisniewski@ou.edu [Département de Physique and Centre de Recherche en Astrophysique du Québec (CRAQ), Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7 (Canada)

2015-10-01

The SDSS III APOGEE survey recently identified two new σ Ori E type candidates, HD 345439 and HD 23478, which are a rare subset of rapidly rotating massive stars whose large (kGauss) magnetic fields confine circumstellar material around these systems. Our analysis of multi-epoch photometric observations of HD 345439 from the Kilodegree Extremely Little Telescope, Wide Angle Search for Planets, and ASAS surveys reveals the presence of a ∼0.7701 day period in each data set, suggesting the system is among the faster known σ Ori E analogs. We also see clear evidence that the strength of Hα, H i Brackett series lines, and He i lines also vary on a ∼0.7701 day period from our analysis of multi-epoch, multi-wavelength spectroscopic monitoring of the system from the APO 3.5 m telescope. We trace the evolution of select emission line profiles in the system, and observe coherent line profile variability in both optical and infrared H i lines, as expected for rigidly rotating magnetosphere stars. We also analyze the evolution of the H i Br-11 line strength and line profile in multi-epoch observations of HD 23478 from the SDSS-III APOGEE instrument. The observed periodic behavior is consistent with that recently reported by Sikora and collaborators in optical spectra.

New analysis indicates no thermal inversion in the atmosphere of HD 209458b

International Nuclear Information System (INIS)

Diamond-Lowe, Hannah; Stevenson, Kevin B.; Bean, Jacob L.; Line, Michael R.; Fortney, Jonathan J.

2014-01-01

An important focus of exoplanet research is the determination of the atmospheric temperature structure of strongly irradiated gas giant planets, or hot Jupiters. HD 209458b is the prototypical exoplanet for atmospheric thermal inversions, but this assertion does not take into account recently obtained data or newer data reduction techniques. We reexamine this claim by investigating all publicly available Spitzer Space Telescope secondary-eclipse photometric data of HD 209458b and performing a self-consistent analysis. We employ data reduction techniques that minimize stellar centroid variations, apply sophisticated models to known Spitzer systematics, and account for time-correlated noise in the data. We derive new secondary-eclipse depths of 0.119% ± 0.007%, 0.123% ± 0.006%, 0.134% ± 0.035%, and 0.215% ± 0.008% in the 3.6, 4.5, 5.8, and 8.0 μm bandpasses, respectively. We feed these results into a Bayesian atmospheric retrieval analysis and determine that it is unnecessary to invoke a thermal inversion to explain our secondary-eclipse depths. The data are well fitted by a temperature model that decreases monotonically between pressure levels of 1 and 0.01 bars. We conclude that there is no evidence for a thermal inversion in the atmosphere of HD 209458b.

HD 97658 and its super-Earth

Directory of Open Access Journals (Sweden)

Van Grootel V.

2015-01-01

Full Text Available Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present the confirmation, based on Spitzer observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass (M* = 0.77 ± 0.05 M⊙ K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck-HIRES radial velocities, and MOST and Spitzer photometry. HD 97658 b is a massive (MP = 7.55−0.79+0.83 M⊕ and large (RP = 2.247−0.095+0.098 R⊕ at 4.5 μm super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, by at least 60% by mass, and very little H-He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age.

Studies of FCAPT uvby Photometry with Period04: The mCP Stars HD 5797, HD 36792, HD 27309, HD 47913, HD 74521, HD 120198, HD 171263, and HD 215441

Science.gov (United States)

Dukes, Robert J., Jr.; Adelman, Saul J.

2018-04-01

We present differential Strömgren uvby Four College Automated Photometric Telescope (FCAPT) observations of eight magnetic chemically peculiar stars: HD 5797, HD 26792, HD 27309, HD 49713, HD 74521, HD 120198, HD 171263, and HD 215441. Our data sets are larger than those of most mCP stars in the literature. These are the first FCAPT observations of HD 5797, HD 26792, HD 49713, and HD 171263. Those for the other four stars substantially extend published FCAPT data sets. The FCAPT has observed some stars for a longer time range and with greater accuracy than other optical region telescopes. We determine very accurate periods and u, v, b, and y amplitudes, as well as if there are any long-term periods. Further, we compare our results with those of magnetic field measurements, when they exist, to help interpret the light curves. For each star, we used the Period04 computer program to analyze the uvby light curves. This program provides errors for the derived quantities. Our derived periods of 68.0457 ± 0.0200 days for HD 5797, 3.80205 ± 0.00015 days for HD 26792, 1.5688908 ± 0.0000046 days for HD 27309, 2.135361 ± 0.000031 days for HD 49713, 7.05053 ± 0.00024 for days HD 74521, 1.3857690 ± 0.0000058 days for HD 120198, 3.99744 ± 0.00015 days for HD 171263, and 9.487792 ± 0.000049 days for HD 215441 are refinements of the last determinations in the literature. We also found a low-frequency term for HD 49713 in all four filters.

RADIAL VELOCITY PLANETS DE-ALIASED: A NEW, SHORT PERIOD FOR SUPER-EARTH 55 Cnc e

International Nuclear Information System (INIS)

Dawson, Rebekah I.; Fabrycky, Daniel C.

2010-01-01

Radial velocity measurements of stellar reflex motion have revealed many extrasolar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581 d, the distinction between an alias and the true frequency was the distinction between a frozen, dead planet and a planet possibly hospitable to life. To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876 d and HD 75898 b. We find that the true periods of Gl 581 d and HD 73526 b/c remain ambiguous. We revise the periods of HD 156668 b and 55 Cnc e, which were afflicted by daily aliases. For HD 156668 b, the correct period is 1.2699 days and the minimum mass is (3.1 ± 0.4) M + . For 55 Cnc e, the correct period is 0.7365 days-the shortest of any known planet-and the minimum mass is (8.3 ± 0.3) M + . This revision produces a significantly improved five-planet Keplerian fit for 55 Cnc, and a self-consistent dynamical fit describes the data just as well. As radial velocity techniques push to ever-smaller planets, often found in systems of multiple planets, distinguishing true periods from aliases will become increasingly important.

SUBSTELLAR-MASS COMPANIONS TO THE K-GIANTS HD 240237, BD +48 738, AND HD 96127

International Nuclear Information System (INIS)

Gettel, S.; Wolszczan, A.; Niedzielski, A.; Nowak, G.; Adamów, M.; Zieliński, P.; Maciejewski, G.

2012-01-01

We present the discovery of substellar-mass companions to three giant stars by the ongoing Penn State-Toruń Planet Search conducted with the 9.2 m Hobby-Eberly Telescope. The most massive of the three stars, K2-giant HD 240237, has a 5.3 M J minimum mass companion orbiting the star at a 746 day period. The K0-giant BD +48 738 is orbited by a ≥0.91 M J planet which has a period of 393 days and shows a nonlinear, long-term radial velocity (RV) trend that indicates a presence of another, more distant companion, which may have a substellar mass or be a low-mass star. The K2-giant HD 96127 has a ≥4.0 M J mass companion in a 647 day orbit around the star. The two K2-giants exhibit a significant RV noise that complicates the detection of low-amplitude, periodic variations in the data. If the noise component of the observed RV variations is due to solar-type oscillations, we show, using all the published data for the substellar companions to giants, that its amplitude is anti-correlated with stellar metallicity.

Polarized Light Imaging of the HD 142527 Transition Disk with the Gemini Planet Imager: Dust around the Close-in Companion

Science.gov (United States)

Rodigas, Timothy J.; Follette, Katherine B.; Weinberger, Alycia; Close, Laird; Hines, Dean C.

2014-08-01

When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ~100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ~12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95-1.14 μm). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point source in polarized light that may be spatially separated by ~ a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually confirmed to be spatially separated, this system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministrio da Cincia, Tecnologia e Inovao (Brazil), and Ministerio de Ciencia, Tecnologa e Innovacin Productiva (Argentina).

HD 285507b

DEFF Research Database (Denmark)

Quinn, Samuel N.; White, Russel J.; Latham, David W.

2014-01-01

We report the discovery of the first hot Jupiter in the Hyades open cluster. HD 285507b orbits a V = 10.47 K4.5V dwarf (M * = 0.734 M ☉; R * = 0.656 R ☉) in a slightly eccentric () orbit with a period of days. The induced stellar radial velocity corresponds to a minimum companion mass of M Psin i...... timescale for HD 285507b to be larger than the age of the Hyades, which may indicate that this planet's non-zero eccentricity is the result of migration via interactions with a third body. We also demonstrate a significant difference between the eccentricity distributions of hot Jupiters that have had time...... to tidally circularize and those that have not, which we interpret as evidence against Type II migration in the final stages of hot Jupiter formation. Finally, the dependence of the circularization timescale on the planetary tidal quality factor, Q P, allows us to constrain the average value for hot Jupiters to be ....

Gemini Planet Imager Exoplanet Survey: Key Results Two Years Into The Survey

Science.gov (United States)

Marchis, Franck; Rameau, Julien; Nielsen, Eric L.; De Rosa, Robert J.; Esposito, Thomas; Draper, Zachary H.; Macintosh, Bruce; Graham, James R.; GPIES

2016-10-01

The Gemini Planet Imager Exoplanet Survey (GPIES) is targeting 600 young, nearby stars using the GPI instrument. We report here on recent results obtained with this instrument from our team.Rameau et al. (ApJL, 822 2, L2, 2016) presented astrometric monitoring of the young exoplanet HD 95086 b obtained with GPI between 2013 and 2016. Efficient Monte Carlo techniques place preliminary constraints on the orbital parameters of HD 95086 b. Under the assumption of a coplanar planet-disk system, the periastron of HD 95086 b is beyond 51 AU. Therefore, HD 95086 b cannot carve the entire gap inferred from the measured infrared excess in the SED of HD 95086. Additional photometric and spectroscopic measurements reported by de Rosa et al. (2016, apJ, in press) showed that the spectral energy distribution of HD 95086 b is best fit by low temperature (T~800-1300 K), low surface gravity spectra from models which simulate high photospheric dust content. Its temperature is typical to L/T transition objects, but the spectral type is poorly constrained. HD 95086 b is an important exoplanet to test our models of atmospheric properties of young extrasolar planets.Direct detections of debris disk are keys to infer the collisional past and understand the formation of planetary systems. Two debris disks were recently studied with GPI:- Draper et al. (submitted to ApJ, 2016) show the resolved circumstellar debris disk around HD 111520 at a projected range of ~30-100 AU using both total and polarized H-band intensity. Structures in the disks such as a large brightness asymmetry and symmetric polarization fraction are seen. Additional data would confirm if a large disruption event from a stellar fly-by or planetary perturbations altered the disk density- Esposito et al. (submitted to ApJ, 2016) combined Keck NIRC2 data taken at 1.2-2.3 microns and GPI 1.6 micron total intensity and polarized light detections that probes down to projected separations less than 10 AU to show that the HD

A SEARCH FOR MULTI-PLANET SYSTEMS USING THE HOBBY-EBERLY TELESCOPE

International Nuclear Information System (INIS)

Wittenmyer, Robert A.; Endl, Michael; Cochran, William D.; Levison, Harold F.; Henry, Gregory W.

2009-01-01

Extrasolar multiple-planet systems provide valuable opportunities for testing theories of planet formation and evolution. The architectures of the known multiple-planet systems demonstrate a fascinating level of diversity, which motivates the search for additional examples of such systems in order to better constrain their formation and dynamical histories. Here we describe a comprehensive investigation of 22 planetary systems in an effort to answer three questions: (1) are there additional planets? (2) where could additional planets reside in stable orbits? and (3) what limits can these observations place on such objects? We find no evidence for additional bodies in any of these systems; indeed, these new data do not support three previously announced planets (HD 20367 b: Udry et al.; HD 74156 d: Bean et al.; and 47 UMa c: Fischer et al.). The dynamical simulations show that nearly all of the 22 systems have large regions in which additional planets could exist in stable orbits. The detection-limit computations indicate that this study is sensitive to close-in Neptune-mass planets for most of the systems targeted. We conclude with a discussion on the implications of these nondetections.

The Case of the Tail Wagging the Dog: HD 189733 - Evidence of Hot Jupiter Exoplanets Spinning-up Their Host Stars

Science.gov (United States)

Guinan, E. F.

2013-06-01

(Abstract only) HD 189733A is an eighth mag K1.5V star that has attracted much attention because it hosts a short period, transiting, hot-Jupiter planet. This planet, HD 189733b, has one of the shortest known orbital periods (P = 2.22 days) and is only 0.031 AU from its host star. Because the system undergoes eclipses and is bright, HD 189733 has been extensively studied. The planet's atmosphere has been found to contain water vapor, methane, CO2, and sodium and possible haze. Spitzer IR observations indicate planet temperature, varying ~970 K to ~1,200 K over its surface (Tinetti (2007). Based on measurements of the K-star's P(rot) from starspot modulations of ~11.95 d, strong coronal X-ray emission and chromospheric Ca II-HK emission indicate a young age of ~0.7 Gyr. But this apparent young age is discrepant with a much older age (> 4 Gyr) inferred from the star's very low Lithium abundance. However, the age of the HD 189733 system can be independently determined by the presence of a faint dM4 companion (HD 189733B) some 12" away. Our Age-Activity relations for this star (no detectable coronal X-ray emission and no H-alpha emission) indicate an age > 4 Gyr (and < 8 Gyr from kinematics and metallicity). This age should apply to its K star companion and its planet. The fast rotation and resultant high activity levels of the K star can best be explained from the increase in its (rotation) angular momentum (AM) from the orbital AM of the planet. This AM transfer occurs from tidal and magnetic interactions of the K star with its planet. Determining the possible decrease in the planet's orbital period is possible from studying the planet eclipse times (which can be done by AAVSO members with CCD photometry). We also discuss the properties of other related short-period exoplanet systems found by the Kepler Mission that show similar behavior - in that close-in hot Jupiter size planets appear to be physically interacting with their host stars. This work is supported by

The hottest planet.

Science.gov (United States)

Harrington, Joseph; Luszcz, Statia; Seager, Sara; Deming, Drake; Richardson, L Jeremy

2007-06-07

Of the over 200 known extrasolar planets, just 14 pass in front of and behind their parent stars as seen from Earth. This fortuitous geometry allows direct determination of many planetary properties. Previous reports of planetary thermal emission give fluxes that are roughly consistent with predictions based on thermal equilibrium with the planets' received radiation, assuming a Bond albedo of approximately 0.3. Here we report direct detection of thermal emission from the smallest known transiting planet, HD 149026b, that indicates a brightness temperature (an expression of flux) of 2,300 +/- 200 K at 8 microm. The planet's predicted temperature for uniform, spherical, blackbody emission and zero albedo (unprecedented for planets) is 1,741 K. As models with non-zero albedo are cooler, this essentially eliminates uniform blackbody models, and may also require an albedo lower than any measured for a planet, very strong 8 microm emission, strong temporal variability, or a heat source other than stellar radiation. On the other hand, an instantaneous re-emission blackbody model, in which each patch of surface area instantly re-emits all received light, matches the data. This planet is known to be enriched in heavy elements, which may give rise to novel atmospheric properties yet to be investigated.

Advection of Potential Temperature in the Atmosphere of Irradiated Exoplanets: A Robust Mechanism to Explain Radius Inflation

Science.gov (United States)

Tremblin, P.; Chabrier, G.; Mayne, N. J.; Amundsen, D. S.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J.; Fromang, S.

2017-01-01

The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth's atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.

Advection of Potential Temperature in the Atmosphere of Irradiated Exoplanets: A Robust Mechanism to Explain Radius Inflation

International Nuclear Information System (INIS)

Tremblin, P.; Chabrier, G.; Mayne, N. J.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J.; Amundsen, D. S.; Fromang, S.

2017-01-01

The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth’s atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.

Advection of Potential Temperature in the Atmosphere of Irradiated Exoplanets: A Robust Mechanism to Explain Radius Inflation

Energy Technology Data Exchange (ETDEWEB)

Tremblin, P. [Maison de la Simulation, CEA-CNRS-INRIA-UPS-UVSQ, USR 3441, CEA Paris-Saclay, F-91191 Gif-Sur-Yvette (France); Chabrier, G.; Mayne, N. J.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J. [Astrophysics Group, University of Exeter, EX4 4QL Exeter (United Kingdom); Amundsen, D. S. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10025 (United States); Fromang, S., E-mail: pascal.tremblin@cea.fr [Laboratoire AIM, CEA/DSM-CNRS-Université Paris 7, Irfu/Service d’Astrophysique, CEA Paris-Saclay, F-91191 Gif-sur-Yvette (France)

2017-05-20

The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth’s atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.

GAP CLEARING BY PLANETS IN A COLLISIONAL DEBRIS DISK

Energy Technology Data Exchange (ETDEWEB)

Nesvold, Erika R. [Department of Physics, University of Maryland Baltimore County 1000 Hilltop Circle Baltimore, MD 21250 (United States); Kuchner, Marc J., E-mail: Erika.Nesvold@umbc.edu, E-mail: Marc.Kuchner@nasa.gov [NASA Goddard Space Flight Center Exoplanets and Stellar Astrophysics Laboratory, Code 667 Greenbelt, MD 21230 (United States)

2015-01-10

We apply our 3D debris disk model, SMACK, to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (α = 2/7). We find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index α of the power law depends on the age of the system t relative to the collisional timescale t {sub coll} of the disk by α = 0.32(t/t {sub coll}){sup –0.04}, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion resonances near the chaotic zone. We investigate the effects of the initial eccentricity distribution of the disk particles and find a negligible effect on the gap size at Jovian planet masses, since collisions tend to erase memory of the initial particle eccentricity distributions. Finally, we find that the presence of Trojan analogs is a potentially powerful diagnostic of planets in the mass range ∼1-10 M {sub Jup}. We apply our model to place new upper limits on planets around Fomalhaut, HR 4796 A, HD 202628, HD 181327, and β Pictoris.

GAP CLEARING BY PLANETS IN A COLLISIONAL DEBRIS DISK

International Nuclear Information System (INIS)

Nesvold, Erika R.; Kuchner, Marc J.

2015-01-01

We apply our 3D debris disk model, SMACK, to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (α = 2/7). We find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index α of the power law depends on the age of the system t relative to the collisional timescale t coll of the disk by α = 0.32(t/t coll ) –0.04 , with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion resonances near the chaotic zone. We investigate the effects of the initial eccentricity distribution of the disk particles and find a negligible effect on the gap size at Jovian planet masses, since collisions tend to erase memory of the initial particle eccentricity distributions. Finally, we find that the presence of Trojan analogs is a potentially powerful diagnostic of planets in the mass range ∼1-10 M Jup . We apply our model to place new upper limits on planets around Fomalhaut, HR 4796 A, HD 202628, HD 181327, and β Pictoris

Simulation of polarimetric effects in planetary system HD 189733

Science.gov (United States)

Frantseva, K.; Kostogryz, N. M.; Yakobchuk, T. M.

2012-11-01

In this paper we present results of linear polarization modelling for HD 189733 in the U filter using the Monte Carlo method. Our simulations are based on the well known effect that linear polarization of a centrosymmetric unresolved star becomes non-zero during the planet transit or in the presence of spots on its surface. HD 189733 is currently the brightest (m_{V}=7.67^{m}) known star to harbour a transiting exoplanet. This fact, along with the short orbital period (2.2 d), makes it very suitable for different types of observations including polarimetry. Since we are interested in occultation effects, a very important parameter is the ratio of the planet to star radii, which is also very large (0.15). As the host star is active and spots may cover up to 1% of the planetary surface, we perform our simulations for different spot parameters such as sizes, locations on the stellar disk, and temperatures.

Searching for stable orbits in the HD 10180 planetary system

Directory of Open Access Journals (Sweden)

Laskar J.

2011-02-01

Full Text Available A planetary system with at least seven planets has been found around the star HD 10180. However, the traditional Keplerian and n-body fits to the data provide an orbital solution that becomes unstable very quickly, which may quest the reliability of the observations. Here we show that stable orbital configurations can be obtained if general relativity and long-term dissipation raised by tides on the innermost planet are taken into account.

A HOT URANUS ORBITING THE SUPER METAL-RICH STAR HD 77338 AND THE METALLICITY-MASS CONNECTION

International Nuclear Information System (INIS)

Jenkins, J. S.; Hoyer, S.; Jones, M. I.; Rojo, P.; Day-Jones, A. C.; Ruiz, M. T.; Jones, H. R. A.; Tuomi, M.; Barnes, J. R.; Pavlenko, Y. V.; Pinfield, D. J.; Murgas, F.; Ivanyuk, O.; Jordán, A.

2013-01-01

We announce the discovery of a low-mass planet orbiting the super metal-rich K0V star HD 77338 as part of our ongoing Calan-Hertfordshire Extrasolar Planet Search. The best-fit planet solution has an orbital period of 5.7361 ± 0.0015 days and with a radial velocity semi-amplitude of only 5.96 ± 1.74 ms –1 , we find a minimum mass of 15.9 +4.7 -5.3 M ⊕ . The best-fit eccentricity from this solution is 0.09 +0.25 -0.09 , and we find agreement for this data set using a Bayesian analysis and a periodogram analysis. We measure a metallicity for the star of +0.35 ± 0.06 dex, whereas another recent work finds +0.47 ± 0.05 dex. Thus HD 77338b is one of the most metal-rich planet-host stars known and the most metal-rich star hosting a sub-Neptune-mass planet. We searched for a transit signature of HD 77338b but none was detected. We also highlight an emerging trend where metallicity and mass seem to correlate at very low masses, a discovery that would be in agreement with the core accretion model of planet formation. The trend appears to show that for Neptune-mass planets and below, higher masses are preferred when the host star is more metal-rich. Also a lower boundary is apparent in the super metal-rich regime where there are no very low mass planets yet discovered in comparison to the sub-solar metallicity regime. A Monte Carlo analysis shows that this low-mass planet desert is statistically significant with the current sample of 36 planets at the ∼4.5σ level. In addition, results from Kepler strengthen the claim for this paucity of the lowest-mass planets in super metal-rich systems. Finally, this discovery adds to the growing population of low-mass planets around low-mass and metal-rich stars and shows that very low mass planets can now be discovered with a relatively small number of data points using stable instrumentation.

New Constraints on Turbulence and Embedded Planet Mass in the HD 163296 Disk from Planet–Disk Hydrodynamic Simulations

Science.gov (United States)

Liu, Shang-Fei; Jin, Sheng; Li, Shengtai; Isella, Andrea; Li, Hui

2018-04-01

Recent Atacama Large Millimeter and Submillimeter Array (ALMA) observations of the protoplanetary disk around the Herbig Ae star HD 163296 revealed three depleted dust gaps at 60, 100, and 160 au in the 1.3 mm continuum as well as CO depletion in the middle and outer dust gaps. However, no CO depletion was found in the inner dust gap. To examine the planet–disk interaction model, we present results of 2D two fluid (gas + dust) hydrodynamic simulations coupled with 3D radiative transfer simulations. To fit the high gas-to-dust ratio of the first gap, we find that the Shakura–Sunyaev viscosity parameter α must be very small (≲ {10}-4) in the inner disk. On the other hand, a relatively large α (∼ 7.5× {10}-3) is required to reproduce the dust surface density in the outer disk. We interpret the variation of α as an indicator of the transition from an inner dead zone to the outer magnetorotational instability (MRI) active zone. Within ∼100 au, the HD 163296 disk’s ionization level is low, and non-ideal magnetohydrodynamic effects could suppress the MRI, so the disk can be largely laminar. The disk’s ionization level gradually increases toward larger radii, and the outermost disk (r> 300 au) becomes turbulent due to MRI. Under this condition, we find that the observed dust continuum and CO gas line emissions can be reasonably fit by three half-Jovian-mass planets (0.46, 0.46, and 0.58 {M}{{J}}) at 59, 105, and 160 au, respectively.

X-rays from HD 100546- A Young Herbig Star Orbited by Giant Protoplanets

Science.gov (United States)

Skinner, Stephen

A protoplanetary system consisting of at least two giant planets has beendetected orbiting the young nearby Herbig Be star HD 100546. The inner protoplanet orbits inside a gap within 14 AU of the star and is exposed to strong stellar UV and X-ray radiation. The detection of very warm disk gas provides evidence that stellar heating is affecting physical conditions in the planet-forming environment. We obtained a deep 74 ksec X-ray observation of HD 100546 in 2015 with XMM-Newton yielding an excellent-quality spectrum. We propose here to analyze the XMM-Newton data to determine the X-ray ionization and heating rates in the disk. X-ray ionization and heating affect the thermal and chemical structure of the disk and are key parameters for constructing realistic planet formation models. We are requesting ADAP funding to support the analysis and publication of this valuable XMM-Newton data set, which is now in the public archive.

'Signs of disequilibrium chemistry in extrasolar hot-Jupiter type planets?'

Science.gov (United States)

Rocha, Graca; Swain, Mark; Line, Michael; West, Robert

2018-01-01

In the recent years Infrared spectroscopy of hot exoplanets has been revealing their atmospheric composition. For example the spectra of the planet HD189733b exhibits signatures of CH4, CO2, CO and H2O molecules (Swain et al 2008, 2009, etc.). The original 2008 detection of CH4 was a surprise because it is not thermochemically favored at the relatively high temperature (~1300 K) of the atmosphere of HD 189733b. More recent analysis of HD 189733b measurements (Swain, Line, Deroo 2014) implied a CH4 enhancement of ~1000x greater than has been assumed. Significantly more data has recently become available from WFC3 observations (Mccullah et al. 2014, Crozet at al. 2015) of this planet. In the meantime theoretical models by Moses et al. 2011 showed that large enhancement of quenched methane is possible due to transport if vertical eddy diffusion is significant.In this talk we will present results from a new study of CH4 enhancement in the atmosphere of HD189733b. We analysise the transit spectra of this planet obtained with the Hubble Space Telescope, combining the shorter wavelength 1.1-1.6 μm data from WFC3 measurements with the 1.5-2.4 μm data from NICMOS measurements. We also introduce a new methodology, implemented within a Bayesian framework, where hypothesis testing is conducted via evidence based model selection. Our analysis indicates, for the first time, that the observed excess of Methane in HD189733b’s atmosphere requires disequilibrium chemistry. However the Evidence has a modest discriminatory power amongst a subset of models. Furthermore our constraints confirm Swain et al. 2014 results with an excess of Methane with a mixing ratio of 10 2.26 ppm with EvidencelogZ=-58.602 +/- 0.109.

On the inclination and habitability of the HD 10180 system

Energy Technology Data Exchange (ETDEWEB)

Kane, Stephen R. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Gelino, Dawn M., E-mail: skane@sfsu.edu [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2014-09-10

There are numerous multi-planet systems that have now been detected via a variety of techniques. These systems exhibit a range of both planetary properties and orbital configurations. For those systems without detected planetary transits, a significant unknown factor is the orbital inclination. This produces an uncertainty in the mass of the planets and their related properties, such as atmospheric scale height. Here we investigate the HD 10180 system, which was discovered using the radial velocity technique. We provide a new orbital solution for the system which allows for eccentric orbits for all planets. We show how the inclination of the system affects the mass/radius properties of the planets and how the detection of phase signatures may resolve the inclination ambiguity. We finally evaluate the Habitable Zone properties of the system and show that the g planet spends 100% of an eccentric orbit within the Habitable Zone.

Subaru/SCExAO First-light Direct Imaging of a Young Debris Disk around HD 36546

Energy Technology Data Exchange (ETDEWEB)

Currie, Thayne; Guyon, Olivier; Kudo, Tomoyuki; Jovanovic, Nemanja; Lozi, Julien [National Astronomical Observatory of Japan, Subaru Telescope, National Institutes of Natural Sciences, Hilo, HI 96720 (United States); Tamura, Motohide; Kuzuhara, Masayuki [Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo (Japan); Schlieder, Joshua E. [IPAC-NExScI, Mail Code 100-22, Caltech, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Brandt, Timothy D. [Astrophysics Department, Institute for Advanced Study, Princeton, NJ (United States); Kuhn, Jonas [Institute for Astronomy, ETH-Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich (Switzerland); Serabyn, Eugene; Singh, Garima [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA (United States); Janson, Markus [Department of Astronomy, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Carson, Joseph [Department of Physics and Astronomy, College of Charleston, 66 George Street, Charleston, SC (United States); Groff, Tyler; Kasdin, N. Jeremy [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ (United States); McElwain, Michael W.; Grady, Carol [Exoplanets and Stellar Astrophysics Laboratory, Code 667, NASA-Goddard Space Flight Center, Greenbelt, MD (United States); Uyama, Taichi [Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Akiyama, Eiji [Chile Observatory, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo (Japan); and others

2017-02-10

We present H -band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by the HiCIAO camera using the vector vortex coronagraph. SCExAO traces the disk from r ∼ 0.″3 to r ∼1″ (34–114 au). The disk is oriented in a near east–west direction (PA ∼ 75°), is inclined by i ∼ 70°–75°, and is strongly forward-scattering (g > 0.5). It is an extended disk rather than a sharp ring; a second, diffuse dust population extends from the disk’s eastern side. While HD 36546 intrinsic properties are consistent with a wide age range (t ∼ 1–250 Myr), its kinematics and analysis of coeval stars suggest a young age (3–10 Myr) and a possible connection to Taurus-Auriga’s star formation history. SCExAO’s planet-to-star contrast ratios are comparable to the first-light Gemini Planet Imager contrasts; for an age of 10 Myr, we rule out planets with masses comparable to HR 8799 b beyond a projected separation of 23 au. A massive icy planetesimal disk or an unseen super-Jovian planet at r > 20 au may explain the disk’s visibility. The HD 36546 debris disk may be the youngest debris disk yet imaged, is the first newly identified object from the now-operational SCExAO extreme AO system, is ideally suited for spectroscopic follow-up with SCExAO/CHARIS in 2017, and may be a key probe of icy planet formation and planet–disk interactions.

Subaru/SCExAO First-light Direct Imaging of a Young Debris Disk around HD 36546

International Nuclear Information System (INIS)

Currie, Thayne; Guyon, Olivier; Kudo, Tomoyuki; Jovanovic, Nemanja; Lozi, Julien; Tamura, Motohide; Kuzuhara, Masayuki; Schlieder, Joshua E.; Brandt, Timothy D.; Kuhn, Jonas; Serabyn, Eugene; Singh, Garima; Janson, Markus; Carson, Joseph; Groff, Tyler; Kasdin, N. Jeremy; McElwain, Michael W.; Grady, Carol; Uyama, Taichi; Akiyama, Eiji

2017-01-01

We present H -band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by the HiCIAO camera using the vector vortex coronagraph. SCExAO traces the disk from r ∼ 0.″3 to r ∼1″ (34–114 au). The disk is oriented in a near east–west direction (PA ∼ 75°), is inclined by i ∼ 70°–75°, and is strongly forward-scattering (g > 0.5). It is an extended disk rather than a sharp ring; a second, diffuse dust population extends from the disk’s eastern side. While HD 36546 intrinsic properties are consistent with a wide age range (t ∼ 1–250 Myr), its kinematics and analysis of coeval stars suggest a young age (3–10 Myr) and a possible connection to Taurus-Auriga’s star formation history. SCExAO’s planet-to-star contrast ratios are comparable to the first-light Gemini Planet Imager contrasts; for an age of 10 Myr, we rule out planets with masses comparable to HR 8799 b beyond a projected separation of 23 au. A massive icy planetesimal disk or an unseen super-Jovian planet at r > 20 au may explain the disk’s visibility. The HD 36546 debris disk may be the youngest debris disk yet imaged, is the first newly identified object from the now-operational SCExAO extreme AO system, is ideally suited for spectroscopic follow-up with SCExAO/CHARIS in 2017, and may be a key probe of icy planet formation and planet–disk interactions.

What is the Mass of a Gap-opening Planet?

Energy Technology Data Exchange (ETDEWEB)

Dong, Ruobing [Steward Observatory, University of Arizona, Tucson, AZ (United States); Fung, Jeffrey, E-mail: rdong@email.arizona.edu [Department of Astronomy, University of California, Berkeley, CA (United States)

2017-02-01

High-contrast imaging instruments such as GPI and SPHERE are discovering gap structures in protoplanetary disks at an ever faster pace. Some of these gaps may be opened by planets forming in the disks. In order to constrain planet formation models using disk observations, it is crucial to find a robust way to quantitatively back out the properties of the gap-opening planets, in particular their masses, from the observed gap properties, such as their depths and widths. Combining 2D and 3D hydrodynamics simulations with 3D radiative transfer simulations, we investigate the morphology of planet-opened gaps in near-infrared scattered-light images. Quantitatively, we obtain correlations that directly link intrinsic gap depths and widths in the gas surface density to observed depths and widths in images of disks at modest inclinations under finite angular resolution. Subsequently, the properties of the surface density gaps enable us to derive the disk scale height at the location of the gap h , and to constrain the quantity M {sub p}{sup 2}/ α , where M {sub p} is the mass of the gap-opening planet and α characterizes the viscosity in the gap. As examples, we examine the gaps recently imaged by VLT/SPHERE, Gemini/GPI, and Subaru/HiCIAO in HD 97048, TW Hya, HD 169142, LkCa 15, and RX J1615.3-3255. Scale heights of the disks and possible masses of the gap-opening planets are derived assuming each gap is opened by a single planet. Assuming α = 10{sup −3}, the derived planet masses in all cases are roughly between 0.1 and 1 M {sub J}.

INFRARED ECLIPSES OF THE STRONGLY IRRADIATED PLANET WASP-33b, AND OSCILLATIONS OF ITS HOST STAR

Energy Technology Data Exchange (ETDEWEB)

Deming, Drake; Fraine, Jonathan D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Sada, Pedro V. [Department of Mathematics and Physics, Universidad de Monterrey, Monterrey (Mexico); Madhusudhan, Nikku [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Harrington, Joseph; Blecic, Jasmina; Nymeyer, Sarah [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Smith, Alexis M. S. [Astrophysics Group, Keele University, Staffordshire ST5 5BG (United Kingdom); Jackson, Brian, E-mail: ddeming@astro.umd.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States)

2012-08-01

We observe two secondary eclipses of the strongly irradiated transiting planet WASP-33b, in the K{sub s} band at 2.15 {mu}m, and one secondary eclipse each at 3.6 {mu}m and 4.5 {mu}m using Warm Spitzer. This planet orbits an A5V {delta}-Scuti star that is known to exhibit low-amplitude non-radial p-mode oscillations at about 0.1% semi-amplitude. We detect stellar oscillations in all of our infrared eclipse data, and also in one night of observations at J band (1.25 {mu}m) out of eclipse. The oscillation amplitude, in all infrared bands except K{sub s} , is about the same as in the optical. However, the stellar oscillations in K{sub s} band (2.15 {mu}m) have about twice the amplitude (0.2%) as seen in the optical, possibly because the Brackett-{gamma} line falls in this bandpass. As regards the exoplanetary eclipse, we use our best-fit values for the eclipse depth, as well as the 0.9 {mu}m eclipse observed by Smith et al., to explore possible states of the exoplanetary atmosphere, based on the method of Madhusudhan and Seager. On this basis we find two possible states for the atmospheric structure of WASP-33b. One possibility is a non-inverted temperature structure in spite of the strong irradiance, but this model requires an enhanced carbon abundance (C/O > 1). The alternative model has solar composition, but an inverted temperature structure. Spectroscopy of the planet at secondary eclipse, using a spectral resolution that can resolve the water vapor band structure, should be able to break the degeneracy between these very different possible states of the exoplanetary atmosphere. However, both of those model atmospheres absorb nearly all of the stellar irradiance with minimal longitudinal re-distribution of energy, strengthening the hypothesis of Cowan and Agol that the most strongly irradiated planets circulate energy poorly. Our measurement of the central phase of the eclipse yields ecos {omega} = 0.0003 {+-} 0.00013, which we regard as being consistent with a

The HARPS-N Rocky Planet Search

DEFF Research Database (Denmark)

Motalebi, F.; Udry, S.; Gillon, M.

2015-01-01

We know now from radial velocity surveys and transit space missions that planets only a few times more massive than our Earth are frequent around solar-type stars. Fundamental questions about their formation history, physical properties, internal structure, and atmosphere composition are, however......, still to be solved. We present here the detection of a system of four low-mass planets around the bright (V = 5.5) and close-by (6.5 pc) star HD 219134. This is the first result of the Rocky Planet Search programme with HARPS-N on the Telescopio Nazionale Galileo in La Palma. The inner planet orbits...... on a close-in, quasi-circular orbit with a period of 6.767 ± 0.004 days. The third planet in the system has a period of 46.66 ± 0.08 days and a minimum-mass of 8.94 ± 1.13 M⊕, at 0.233 ± 0.002 AU from the star. Its eccentricity is 0.46 ± 0.11. The period of this planet is close to the rotational period...

CANDIDATE PLANETS IN THE HABITABLE ZONES OF KEPLER STARS

International Nuclear Information System (INIS)

Gaidos, Eric

2013-01-01

A key goal of the Kepler mission is the discovery of Earth-size transiting planets in ''habitable zones'' where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate stellar parameters, but most Kepler systems are faint, making spectroscopy difficult and prioritization of targets desirable. The parameters of 2035 host stars were estimated by Bayesian analysis and the probabilities p HZ that 2738 candidate or confirmed planets orbit in the habitable zone were calculated. Dartmouth Stellar Evolution Program models were compared to photometry from the Kepler Input Catalog, priors for stellar mass, age, metallicity and distance, and planet transit duration. The analysis yielded probability density functions for calculating confidence intervals of planet radius and stellar irradiance, as well as p HZ . Sixty-two planets have p HZ > 0.5 and a most probable stellar irradiance within habitable zone limits. Fourteen of these have radii less than twice the Earth; the objects most resembling Earth in terms of radius and irradiance are KOIs 2626.01 and 3010.01, which orbit late K/M-type dwarf stars. The fraction of Kepler dwarf stars with Earth-size planets in the habitable zone (η ⊕ ) is 0.46, with a 95% confidence interval of 0.31-0.64. Parallaxes from the Gaia mission will reduce uncertainties by more than a factor of five and permit definitive assignments of transiting planets to the habitable zones of Kepler stars.

Two drastically different climate states on an Earth-like land planet with overland water recycling

Science.gov (United States)

Kalidindi, S.; Reick, C. H.; Raddatz, T.; Claussen, M.

2017-12-01

Prior studies have demonstrated that habitable areas on low-obliquity land planets are confined to the edges of frozen ice caps. Whether such dry planets can maintain long-lived liquid water is unclear. Leconte et al. 2013 argue that on such planets mechanisms like gravity driven ice flows and geothermal flux can maintain liquid water at the edges of thick ice caps and this water may flow back to the lower latitudes through rivers. However, there exists no modelling study which investigates the climate of an Earth-like land planet with an overland recycling mechanism bringing fresh water back from higher to lower latitudes. In our study, by using a comprehensive climate model ICON, we find that an Earth-like land planet with an overland recycling mechanism can exist in two drastically different climate states for the same set of boundary conditions and parameter values: A Cold and Wet (CW) state with dominant low-latitude precipitation and, a Hot and Dry (HD) state with only high-latitude precipitation. For perpetual equinox conditions, both climate states are stable below a certain threshold value of background soil albedo (α) while above that only the CW state is stable. Starting from the HD state and increasing α above the threshold causes an abrupt shift from the HD state to the CW state resulting in a sudden cooling of about 35°C globally which is of the order of the temperature difference between the present-day and the Snowball Earth state. In contrast to the Snowball Earth instability, we find that the sudden cooling in our study is driven by the cloud albedo feedback rather than the snow-albedo feedback. Also, when α in the CW state is reduced back to zero the land planet does not display a closed hysteresis. Our study also has implications for the habitability of Earth-like land planets. At the inner edge of the habitable zone, the higher cloud cover in the CW state cools the planet and may prevent the onset of a runaway greenhouse state. At the outer

WHY ARE PULSAR PLANETS RARE?

Energy Technology Data Exchange (ETDEWEB)

Martin, Rebecca G.; Livio, Mario; Palaniswamy, Divya [Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154 (United States)

2016-12-01

Pulsar timing observations have revealed planets around only a few pulsars. We suggest that the rarity of these planets is due mainly to two effects. First, we show that the most likely formation mechanism requires the destruction of a companion star. Only pulsars with a suitable companion (with an extreme mass ratio) are able to form planets. Second, while a dead zone (a region of low turbulence) in the disk is generally thought to be essential for planet formation, it is most probably rare in disks around pulsars, because of the irradiation from the pulsar. The irradiation strongly heats the inner parts of the disk, thus pushing the inner boundary of the dead zone out. We suggest that the rarity of pulsar planets can be explained by the low probability for these two requirements to be satisfied: a very low-mass companion and a dead zone.

DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b

International Nuclear Information System (INIS)

Moses, Julianne I.; Visscher, C.; Fortney, J. J.; Showman, A. P.; Lewis, N. K.; Griffith, C. A.; Klippenstein, S. J.; Shabram, M.; Friedson, A. J.; Marley, M. S.; Freedman, R. S.

2011-01-01

We have developed a one-dimensional photochemical and thermochemical kinetics and diffusion model to study the effects of disequilibrium chemistry on the atmospheric composition of 'hot-Jupiter' exoplanets. Here we investigate the coupled chemistry of neutral carbon, hydrogen, oxygen, and nitrogen species on HD 189733b and HD 209458b and we compare the model results with existing transit and eclipse observations. We find that the vertical profiles of molecular constituents are significantly affected by transport-induced quenching and photochemistry, particularly on the cooler HD 189733b; however, the warmer stratospheric temperatures on HD 209458b help maintain thermochemical equilibrium and reduce the effects of disequilibrium chemistry. For both planets, the methane and ammonia mole fractions are found to be enhanced over their equilibrium values at pressures of a few bar to less than an mbar due to transport-induced quenching, but CH 4 and NH 3 are photochemically removed at higher altitudes. Disequilibrium chemistry also enhances atomic species, unsaturated hydrocarbons (particularly C 2 H 2 ), some nitriles (particularly HCN), and radicals like OH, CH 3 , and NH 2 . In contrast, CO, H 2 O, N 2 , and CO 2 more closely follow their equilibrium profiles, except at pressures ∼ 2 O, and N 2 are photochemically destroyed and CO 2 is produced before its eventual high-altitude destruction. The enhanced abundances of CH 4 , NH 3 , and HCN are expected to affect the spectral signatures and thermal profiles of HD 189733b and other relatively cool, transiting exoplanets. We examine the sensitivity of our results to the assumed temperature structure and eddy diffusion coefficients and discuss further observational consequences of these models.

Meteorologies of brown dwarfs and extrasolar giant planets

Science.gov (United States)

Cooper, Curtis Steven

2006-06-01

This dissertation explores the consequences of atmospheric dynamics for observations of substellar mass objects (SMOs). Discussed first is the growth of cloud particles of various compositions in brown dwarfs of different surface gravities and effective temperatures. The structure of these objects is calculated with a one-dimensional radiative transfer model. To determine particle sizes, the timescales for microphysical growth processes, including nucleation, coagulation, and coalescence, are compared to the timescale for gravitational sedimentation. The model also allows for sustained uplifting of condensable vapor in convective regions. The results show that particle sizes vary greatly over the range of objects studied. In most cases, clouds on brown dwarfs do not dominate the opacity. Rather, they smooth the emergent spectrum and partially redistribute the radiative energy. The focus then shifts to extrasolar giant planets (EGPs). Results are presented from a three-dimensional model of atmospheric dynamics on the transiting Jupiter-like planet HD 209458b. As a close-in orbiter (known as a "roaster"), HD 209458b is super-heated on its dayside. Due to tidal locking of the interior, the dayside hemisphere faces the star in perpetuity, which leads to very different dynamics than is seen on Jupiter. The flow is characterized by an eastward supersonic jet ( u ~ 4 kms - 1 ) extending from the equator to the mid-latitudes. Temperature contrasts are ~500 K at the photosphere. At 220 mbar, winds blow the hottest regions downstream from the substellar point by ~60°, with direct implications for the infrared light curve. These simulations are extended to the study of carbon chemistry in HD 209458b's atmosphere by coupling the CO/CH 4 reaction kinetics to the dynamics. Disequilibrium results from slow reaction rates at low temperatures and pressures. Effective vertical quenching near the ~3 bar level leads to uniformly high concentrations of CO at the photosphere, even in

An extrasolar planetary system with three Neptune-mass planets.

Science.gov (United States)

Lovis, Christophe; Mayor, Michel; Pepe, Francesco; Alibert, Yann; Benz, Willy; Bouchy, François; Correia, Alexandre C M; Laskar, Jacques; Mordasini, Christoph; Queloz, Didier; Santos, Nuno C; Udry, Stéphane; Bertaux, Jean-Loup; Sivan, Jean-Pierre

2006-05-18

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.

SCExAO and GPI Y JH band photometry and integral field spectroscopy of the young brown dwarf companion to HD 1160

International Nuclear Information System (INIS)

Garcia, Eugenio Victor; Currie, Thayne; Guyon, Olivier

2017-01-01

Here, we present high signal-to-noise ratio, precise Y JH photometry and Y band (0.957–1.120 μm) spectroscopy of HD 1160 B, a young substellar companion discovered from the Gemini NICI Planet Finding Campaign using the Subaru Coronagraphic Extreme Adaptive Optics instrument and the Gemini Planet Imager. HD 1160 B has typical mid-M dwarf-like infrared colors and a spectral type of M5.5_−_0_._5"+"1"."0, where the blue edge of our Y band spectrum rules out earlier spectral types. Atmospheric modeling suggests HD 1160 B has an effective temperature of 3000–3100 K, a surface gravity of log g = 4–4.5, a radius of 1.55 ± 0.10 R J, and a luminosity of log L/L _⊙ = –2.76 ± 0.05. Neither the primary's Hertzspring–Russell diagram position nor atmospheric modeling of HD 1160 B show evidence for a subsolar metallicity. Interpretation of the HD 1160 B spectroscopy depends on which stellar system components are used to estimate the age. Considering HD 1160 A, B and C jointly, we derive an age of 80–125 Myr, implying that HD 1160 B straddles the hydrogen-burning limit (70–90 M _J). If we consider HD 1160 A alone, younger ages (20–125 Myr) and a brown dwarf-like mass (35–90 M _J) are possible. Interferometric measurements of the primary, a precise Gaia parallax, and moderate-resolution spectroscopy can better constrain the system's age and how HD 1160 B fits within the context of (sub)stellar evolution.

Characterization of extra-solar planets and their atmospheres (Spectroscopy of transits and atmospheric escape)

International Nuclear Information System (INIS)

Bourrier, Vincent

2014-01-01

Hot Jupiters are exo-planets so close to their star that their atmosphere can lose gas because of hydrodynamic escape. Transiting gaseous giants are an excellent way to understand this mechanism, but it is necessary to study other types of planets to determine its impact on the exo-planetary population. This thesis aims at using transit spectroscopy to observe the atmosphere of several exo-planets, to study their properties and to contribute to the characterization of hydrodynamic escape. UV lines observed with the Hubble telescope are analyzed with the numerical model of upper atmospheres we developed. Using the Ly-α line we identify energetic and dynamical interactions between the atmospheres of the hot Jupiters HD209458b and HD189733b and their stars. We study the dependence of the escape on the environment of a planet and on its physical properties, through the observation of a super-Earth and a warm Jupiter in the 55 Cnc system. Using observations of HD209458b, we show that magnesium lines are a window on the region of formation of hydrodynamic escape. We study the potential of transit spectroscopy in the near-UV to detect new cases of atmospheric escape. This mechanism is fostered by the proximity of a planet to its star, which makes it even more important to understand the formation and migration processes that can be traced in the alignment of a planetary system. Using measures from the spectrographs HARPS-N and SOPHIE we study the alignments of 55 Cnc e and the Kepler candidate KOI 12.01, whose planetary nature we also seek to validate. (author)

Non-detection of Previously Reported Transits of HD 97658b with MOST Photometry

DEFF Research Database (Denmark)

Dragomir, Diana; Matthews, Jaymie M.; Howard, Andrew W.

2012-01-01

The radial velocity-discovered exoplanet HD 97658b was recently announced to transit, with a derived planetary radius of 2.93 ± 0.28 R ⊕. As a transiting super-Earth orbiting a bright star, this planet would make an attractive candidate for additional observations, including studies of its atmosp...

76 FR 2277 - List of Approved Spent Fuel Storage Casks: NUHOMS® HD System Revision 1

Science.gov (United States)

2011-01-13

... Fuel Storage Casks: NUHOMS[supreg] HD System Revision 1 AGENCY: Nuclear Regulatory Commission. ACTION... System listing within the ``List of Approved Spent Fuel Storage Casks'' to include Amendment No. 1 to... the NUHOMS[supreg] HD Horizontal Modular Storage System for Irradiated Nuclear Fuel. [[Page 2279...

Chemical analysis of three barium stars: HD 51959, HD 88035, and HD 121447

Science.gov (United States)

Karinkuzhi, Drisya; Goswami, Aruna; Sridhar, Navin; Masseron, Thomas; Purandardas, Meenakshi

2018-05-01

We present elemental abundance results from high-resolution spectral analysis of three nitrogen-enhanced barium stars. The analysis is based on spectra obtained with the fibre-fed extended range optical spectrograph attached to 1.52 m telescope at European Southern Observatory, Chile. The spectral resolution is R ˜ 48,000 and the spectral coverage spans from 3500 to 9000Å . For the objects HD 51959 and HD 88035, we present the first-time abundance analyses results. Although a few studies are available in literature on the object HD 121447, the results are significantly different from each other. We have therefore carried out a detailed chemical composition study for this object based on a high-resolution spectrum with high S/N ratio, for a better understanding of the origin of the abundance patterns observed in this star. Stellar atmospheric parameters, the effective temperature, surface gravity, microturbulence, and metallicity of the stars are determined from the local thermodynamic equilibrium analysis using model atmospheres. The metallicities of HD 51959 and HD 88035 are found to be near-solar; they exhibit enhanced abundances of neutron-capture elements. HD 121447 is found to be moderately metal-poor with [Fe/H] = -0.65. While carbon is near-solar in the other two objects, HD 121447 shows carbon enhancement at a level, [C/Fe] = 0.82. Neutron-capture elements are highly enhanced with [X/Fe] > 2 (X: Ba, La, Pr, Nd, Sm) in this object. The α- and iron-peak elements show abundances very similar to field giants with the same metallicity. From kinematic analysis all the three objects are found to be members of thin disc population with a high probability of 0.99, 0.99, and 0.92 for HD 51959, HD 88035, and HD 121447, respectively.

75 FR 25120 - List of Approved Spent Fuel Storage Casks: NUHOMS® HD System Revision 1

Science.gov (United States)

2010-05-07

...] RIN 3150-AI75 List of Approved Spent Fuel Storage Casks: NUHOMS[supreg] HD System Revision 1 AGENCY...), NUHOMS[supreg] HD System listing within the ``List of Approved Spent Fuel Storage Casks'' to include... Modular Storage System for Irradiated Nuclear Fuel. Docket Number: 72-1030. Certificate Expiration Date...

Testing the Mirror World Hypothesis for the Close-In Extrasolar Planets

International Nuclear Information System (INIS)

Foot, R.

2004-01-01

Because planets are not expected to be able to form close to stars due to the high temperatures, it has been suggested that the observed close orbiting (∼ 0.05 AU) large mass planets (∼ M J ) might be mirror worlds - planets composed predominately of mirror matter. The accretion of ordinary matter onto the mirror planet (from e.g. the solar wind from the host star) will make the mirror planet opaque to ordinary radiation with an effective radius R p . It was argued in a previous paper, that this radius was potentially large enough to explain the measured size of the first transiting close-in extrasolar planet, HD209458b. Furthermore, made the rough prediction: R p ∝ √ (T s /M p ), where T s is the surface temperature of the ordinary matter in the mirror planet and M p is the mass of the planet (the latter dependence on M p being the more robust prediction). We compare this prediction with the recently discovered transiting planets, OGLE-TR-56b and OGLE-TR- 113b. (author)

Richest Planetary System Discovered - Up to seven planets orbiting a Sun-like star

Science.gov (United States)

2010-08-01

Astronomers using ESO's world-leading HARPS instrument have discovered a planetary system containing at least five planets, orbiting the Sun-like star HD 10180. The researchers also have tantalising evidence that two other planets may be present, one of which would have the lowest mass ever found. This would make the system similar to our Solar System in terms of the number of planets (seven as compared to the Solar System's eight planets). Furthermore, the team also found evidence that the distances of the planets from their star follow a regular pattern, as also seen in our Solar System. "We have found what is most likely the system with the most planets yet discovered," says Christophe Lovis, lead author of the paper reporting the result. "This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research: the study of complex planetary systems and not just of individual planets. Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the system." The team of astronomers used the HARPS spectrograph, attached to ESO's 3.6-metre telescope at La Silla, Chile, for a six-year-long study of the Sun-like star HD 10180, located 127 light-years away in the southern constellation of Hydrus (the Male Water Snake). HARPS is an instrument with unrivalled measurement stability and great precision and is the world's most successful exoplanet hunter. Thanks to the 190 individual HARPS measurements, the astronomers detected the tiny back and forth motions of the star caused by the complex gravitational attractions from five or more planets. The five strongest signals correspond to planets with Neptune-like masses - between 13 and 25 Earth masses [1] - which orbit the star with periods ranging from about 6 to 600 days. These planets are located between 0.06 and 1.4 times the Earth-Sun distance from their central star. "We also have

VizieR Online Data Catalog: Extrasolar planet HD 189733b whitelight curve (Crouzet+, 2014)

Science.gov (United States)

Crouzet, N.; McCullough, P. R.; Deming, D.; Madhusudhan, N.

2017-05-01

We used HST WFC3 with the newly implemented spatial scanning mode, developed in part to enable observations such as these (McCullough & MacKenty, 2012wfc..rept....8M). In this mode, a controlled scan is applied to the telescope during the exposure in a direction perpendicular to the wavelength dispersion direction (Figure 1). This technique is particularly efficient for bright stars such as HD 189733 (see McCullough et al. 2014ApJ...791...55M, for more details). One eclipse of HD 189733b was observed on 2013 June 24. The observations are divided into five HST orbits, the planetary eclipse occurring during the fourth orbit. In total, 159 exposures of 5.97 s each were acquired, corresponding to 32 exposures per orbit (except for the first orbit in which the first image is a direct image). (1 data file).

Stellar oscillations in planet-hosting giant stars

Energy Technology Data Exchange (ETDEWEB)

Hatzes, Artie P; Zechmeister, Mathias [Thueringer Landessternwarte, Sternwarte 5, D-07778 (Germany)], E-mail: artie@tls-tautenburg.de

2008-10-15

Recently a number of giant extrasolar planets have been discovered around giant stars. These discoveries are important because many of these giant stars have intermediate masses in the range 1.2-3 Msun. Early-type main sequence stars of this mass range have been avoided by radial velocity planet search surveys due the difficulty of getting the requisite radial velocity precision needed for planet discoveries. Thus, giant stars can tell us about planet formation for stars more massive than the sun. However, the determination of stellar masses for giant stars is difficult due to the fact that evolutionary tracks for stars covering a wide range of masses converge to the same region of the H-R diagram. We report here on stellar oscillations in three planet-hosting giant stars: HD 13189, {beta} Gem, and {iota} Dra. Precise stellar radial velocity measurements for these stars show variations whose periods and amplitudes are consistent with solar-like p-mode oscillations. The implied stellar masses for these objects based on the characteristics of the stellar oscillations are consistent with the predictions of stellar isochrones. An investigation of stellar oscillations in planet hosting giant stars offers us the possibility of getting an independent determination of the stellar mass for these objects which is of crucial importance for extrasolar planet studies.

Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

Energy Technology Data Exchange (ETDEWEB)

Crouzet, Nicolas [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); McCullough, Peter R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, Nikku, E-mail: crouzet@dunlap.utoronto.ca [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2014-11-10

Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 μm obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1σ uncertainty is 57 ppm per 0.02 μm bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

Resonant structure, formation and stability of the planetary system HD155358

Science.gov (United States)

Silburt, Ari; Rein, Hanno

2017-08-01

Two Jovian-sized planets are orbiting the star HD155358 near exact mean motion resonance (MMR) commensurability. In this work, we re-analyse the radial velocity (RV) data previously collected by Robertson et al. Using a Bayesian framework, we construct two models - one that includes and the other that excludes gravitational planet-planet interactions (PPIs). We find that the orbital parameters from our PPI and no planet-planet interaction (noPPI) models differ by up to 2σ, with our noPPI model being statistically consistent with previous results. In addition, our new PPI model strongly favours the planets being in MMR, while our noPPI model strongly disfavours MMR. We conduct a stability analysis by drawing samples from our PPI model's posterior distribution and simulating them for 109 yr, finding that our best-fitting values land firmly in a stable region of parameter space. We explore a series of formation models that migrate the planets into their observed MMR. We then use these models to directly fit to the observed RV data, where each model is uniquely parametrized by only three constants describing its migration history. Using a Bayesian framework, we find that a number of migration models fit the RV data surprisingly well, with some migration parameters being ruled out. Our analysis shows that PPIs are important to take into account when modelling observations of multiplanetary systems. The additional information that one can gain from interacting models can help constrain planet migration parameters.

STELLAR ACTIVITY AND EXCLUSION OF THE OUTER PLANET IN THE HD 99492 SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Kane, Stephen R.; Thirumalachari, Badrinath; Hinkel, Natalie R. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Jensen, Eric L. N. [Dept of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Boyajian, Tabetha S.; Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Isaacson, Howard T. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Wright, Jason T., E-mail: skane@sfsu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2016-03-20

A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet signatures, such as radial velocity (RV) variations that originate with the stellar surface rather than the presence of a planet. Here we present an update for the HD 99492 planetary system, using new RV and photometric measurements from the Transit Ephemeris Refinement and Monitoring Survey. Our extended time series and subsequent analyses of the Ca ii H and K emission lines show that the host star has an activity cycle of ∼13 years. The activity cycle correlates with the purported orbital period of the outer planet, the signature of which is thus likely due to the host star activity. We further include a revised Keplerian orbital solution for the remaining planet, along with a new transit ephemeris. Our transit-search observations were inconclusive.

Efforts towards a dynamically polarised HD-target

International Nuclear Information System (INIS)

Radtke, E.; Goertz, St.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Reicherz, G.

2004-01-01

The molecular hydrogen isotopes contain no unpolarisable background. From this point of view they appear to be the material of choice for a polarised bulk target in scattering experiments. The fast nuclear relaxation of H 2 and D 2 is one reason that these substances are not highly polarisable. This fact brings hydrogendeuteride (HD) into focus. In Bochum a device to freeze out gases into the consisting 4 He-cryostat has been built up. The principle of the Dynamic Nuclear Polarisation requires a sufficient amount of paramagnetic electrons. These have been produced by cracking HD molecules at 1 K using a 90 Sr β-source with an activity of 3.7 GBq. Six days of effective irradiation resulted in a density of paramagnetic centres in the order of 10 18 spins/cm 3 . This could be estimated from bolometric electron paramagnetic resonance (EPR) measurements. Dynamic polarisation could not be achieved. This is accounted to isotopic impurities in the used HD, which accelerate the nuclear relaxation. The constant of ortho-para conversion in H 2 could be confirmed to be 1.9%/h

THE INFLUENCE OF THERMAL EVOLUTION IN THE MAGNETIC PROTECTION OF TERRESTRIAL PLANETS

Energy Technology Data Exchange (ETDEWEB)

Zuluaga, Jorge I.; Bustamante, Sebastian; Cuartas, Pablo A. [Instituto de Fisica-FCEN, Universidad de Antioquia, Calle 67 No. 53-108, Medellin (Colombia); Hoyos, Jaime H., E-mail: jzuluaga@fisica.udea.edu.co, E-mail: sbustama@pegasus.udea.edu.co, E-mail: p.cuartas@fisica.udea.edu.co, E-mail: jhhoyos@udem.edu.co [Departamento de Ciencias Basicas, Universidad de Medellin, Carrera 87 No. 30-65, Medellin (Colombia)

2013-06-10

Magnetic protection of potentially habitable planets plays a central role in determining their actual habitability and/or the chances of detecting atmospheric biosignatures. Here we develop a thermal evolution model of potentially habitable Earth-like planets and super-Earths (SEs). Using up-to-date dynamo-scaling laws, we predict the properties of core dynamo magnetic fields and study the influence of thermal evolution on their properties. The level of magnetic protection of tidally locked and unlocked planets is estimated by combining simplified models of the planetary magnetosphere and a phenomenological description of the stellar wind. Thermal evolution introduces a strong dependence of magnetic protection on planetary mass and rotation rate. Tidally locked terrestrial planets with an Earth-like composition would have early dayside magnetopause distances between 1.5 and 4.0 R{sub p} , larger than previously estimated. Unlocked planets with periods of rotation {approx}1 day are protected by magnetospheres extending between 3 and 8 R{sub p} . Our results are robust in comparison with variations in planetary bulk composition and uncertainties in other critical model parameters. For illustration purposes, the thermal evolution and magnetic protection of the potentially habitable SEs GL 581d, GJ 667Cc, and HD 40307g were also studied. Assuming an Earth-like composition, we found that the dynamos of these planets are already extinct or close to being shut down. While GL 581d is the best protected, the protection of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic conditions, seems to be severely exposed to the stellar wind, and, under the conditions of our model, has probably suffered massive atmospheric losses.

Global hydromagnetic simulations of a planet embedded in a dead zone: Gap opening, gas accretion, and formation of a protoplanetary jet

Energy Technology Data Exchange (ETDEWEB)

Gressel, O. [NORDITA, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden); Nelson, R. P. [Astronomy Unit, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Turner, N. J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Ziegler, U., E-mail: oliver.gressel@nordita.org, E-mail: r.p.nelson@qmul.ac.uk, E-mail: neal.j.turner@jpl.nasa.gov, E-mail: uziegler@aip.de [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482, Potsdam (Germany)

2013-12-10

We present global hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations with mesh refinement of accreting planets embedded in protoplanetary disks (PPDs). The magnetized disk includes Ohmic resistivity that depends on the overlying mass column, leading to turbulent surface layers and a dead zone near the midplane. The main results are: (1) the accretion flow in the Hill sphere is intrinsically three-dimensional for HD and MHD models. Net inflow toward the planet is dominated by high-latitude flows. A circumplanetary disk (CPD) forms. Its midplane flows outward in a pattern whose details differ between models. (2) The opening of a gap magnetically couples and ignites the dead zone near the planet, leading to stochastic accretion, a quasi-turbulent flow in the Hill sphere, and a CPD whose structure displays high levels of variability. (3) Advection of magnetized gas onto the rotating CPD generates helical fields that launch magnetocentrifugally driven outflows. During one specific epoch, a highly collimated, one-sided jet is observed. (4) The CPD's surface density is ∼30 g cm{sup −2}, small enough for significant ionization and turbulence to develop. (5) The accretion rate onto the planet in the MHD simulation reaches a steady value 8 × 10{sup –3} M {sub ⊕} yr{sup –1} and is similar in the viscous HD runs. Our results suggest that gas accretion onto a forming giant planet within a magnetized PPD with a dead zone allows rapid growth from Saturnian to Jovian masses. As well as being relevant for giant planet formation, these results have important implications for the formation of regular satellites around gas giant planets.

Dayside atmospheric structure of HD209458b from Spitzer eclipses

Science.gov (United States)

Reinhard, Matthew; Harrington, Joseph; Challener, Ryan; Cubillos, Patricio; Blecic, Jasmina

2017-10-01

HD209458b is a hot Jupiter with a radius of 1.26 ± 0.08 Jupiter radii (Richardson et al, 2006) and a mass of 0.64 ± 0.09 Jupiter masses (Snellen et al, 2010). The planet orbits a G0 type star with an orbital period of 3.52472 ± 2.81699e-05 days, and a relatively low eccentricity of 0.0082 +0.0078/-0.0082 (Wang and Ford 2013). We report the analysis of observations of HD209458b during eclipse, taken in the 3.6 and 4.5 micron channels by the Spitzer Space Telescope's Infrared Array Camera (Program 90186). We produce a photometric light curve of the eclipses in both channels, using our Photometry for Orbits Eclipses and Transits (POET) code, and calculate the brightness temperatures and eclipse depths. We also present best estimates of the atmospheric parameters of HD209458b using our Bayesian Atmospheric Radiative Transfer (BART) code. These are some preliminary results of what will be an analysis of all available Spitzer data for HD209458b. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.

Time-resolved UVES observations of a stellar flare on the planet host HD 189733 during primary transit

Science.gov (United States)

Klocová, T.; Czesla, S.; Khalafinejad, S.; Wolter, U.; Schmitt, J. H. M. M.

2017-11-01

Context. HD 189733 is an exoplanetary system consisting of a transiting hot Jupiter and an active K2V-type main sequence star. Rich manifestations of a stellar activity, like photometric spots or chromospheric flares were repeatedly observed in this system in optical, UV and X-rays. Aims: We aim to use VLT/UVES high resolution (R = 60 000) echelle spectra to study a stellar flare. Methods: We have performed simultaneous analyses of the temporal evolution in several chromospheric stellar lines, namely, the Ca II H & K lines (3933, 3968 Å), H α (6563 Å), H β (4861 Å), H γ (4341 Å), H δ (4102 Å), H ɛ (3970 Å), the Ca II infrared triplet lines (8498, 8542 and 8662 Å), and He I D3 (5875.6 Å). Observations were carried out with a time resolution of approximately 1 min for a duration of four hours, including a complete planetary transit. Results: We determine the energy released during the flare in all studied chromospheric lines combined to be about 8.7 × 1031 erg, which puts this event at the upper end of flare energies observed on the Sun. Our analysis does not reveal any significant delay of the flare peak observed in the Balmer and Ca II H & K lines, although we find a clear difference in the temporal evolution of these lines. The He I D3 shows additional absorption possibly related to the flare event. Based on the flux released in Ca II H & K lines during the flare, we estimate the soft X-ray flux emission to be 7 × 1030 erg. Conclusions: The observed flare can be ranked as a moderate flare on a K-type star and confirms a rather high activity level of HD 189733 host star. The cores of the studied chromospheric lines demonstrate the same behavior and let us study the flare evolution. We demonstrate that the activity of an exoplanet host star can play an important role in the detection of exoplanet atmospheres, since these are frequently discovered as an additional absorption in the line cores. A possible star-planet interaction responsible for a flare

Atmospheric dynamics of tidally synchronized extrasolar planets.

Science.gov (United States)

Cho, James Y-K

2008-12-13

Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

KEPLER-21b: A 1.6 R{sub Earth} PLANET TRANSITING THE BRIGHT OSCILLATING F SUBGIANT STAR HD 179070

Energy Technology Data Exchange (ETDEWEB)

Howell, Steve B. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Rowe, Jason F.; Bryson, Stephen T. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Quinn, Samuel N. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Marcy, Geoffrey W.; Isaacson, Howard [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Chaplin, William J.; Elsworth, Yvonne [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Metcalfe, Travis S. [High Altitude Observatory and Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Monteiro, Mario J. P. F. G. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Appourchaux, Thierry [Institut d' Astrophysique Spatiale, Universite Paris XI-CNRS (UMR8617), Batiment 121, 91405 Orsay Cedex (France); Basu, Sarbani [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Creevey, Orlagh L. [Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Gilliland, Ronald L. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Quirion, Pierre-Olivier [Canadian Space Agency, 6767 Boulevard de l' Aeroport, Saint-Hubert, QC, J3Y 8Y9 (Canada); Stello, Denis [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Kjeldsen, Hans; Christensen-Dalsgaard, Joergen [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Garcia, Rafael A. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot-IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France); and others

2012-02-20

We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R{sub Earth} object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34 {+-} 0.06 M{sub Sun} and 1.86 {+-} 0.04 R{sub Sun }, respectively, as well as yielding an age of 2.84 {+-} 0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3{sigma}) that the transit event is caused by a 1.64 {+-} 0.04 R{sub Earth} exoplanet in a 2.785755 {+-} 0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of {approx}10 M{sub Earth} (2{sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

EXAMINING TATOOINE: ATMOSPHERIC MODELS OF NEPTUNE-LIKE CIRCUMBINARY PLANETS

Energy Technology Data Exchange (ETDEWEB)

May, E. M.; Rauscher, E. [University of Michigan (United States)

2016-08-01

Circumbinary planets experience a time-varying irradiation pattern as they orbit their two host stars. In this work, we present the first detailed study of the atmospheric effects of this irradiation pattern on known and hypothetical gaseous circumbinary planets. Using both a one-dimensional energy balance model (EBM) and a three-dimensional general circulation model (GCM), we look at the temperature differences between circumbinary planets and their equivalent single-star cases in order to determine the nature of the atmospheres of these planets. We find that for circumbinary planets on stable orbits around their host stars, temperature differences are on average no more than 1.0% in the most extreme cases. Based on detailed modeling with the GCM, we find that these temperature differences are not large enough to excite circulation differences between the two cases. We conclude that gaseous circumbinary planets can be treated as their equivalent single-star case in future atmospheric modeling efforts.

EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

KAUST Repository

Piskorz, Danielle; Benneke, Bjö rn; Crockett, Nathan R.; Lockwood, Alexandra C.; Blake, Geoffrey A.; Barman, Travis S.; Bender, Chad F.; Bryan, Marta L.; Carr, John S.; Fischer, Debra A.; Howard, Andrew W.; Isaacson, Howard; Johnson, John A.

2016-01-01

We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations

The TERMS Project: Improved Orbital Parameters and Photometry of HD168443 and the Photometry Pipeline

Science.gov (United States)

Pilyavsky, Genady; Mahadevan, S.; Kane, S. R.; Howard, A. W.; Ciardi, D. R.; de Pree, C.; Dragomir, D.; Fischer, D.; Henry, G. W.; Jensen, E. L. N.; Laughlin, G.; Marlowe, H.; Rabus, M.; von Braun, K.; Wright, J. T.; Wang, X.

2012-01-01

The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) project focuses on updating the ephemerides of known exoplanets, put tighter constraints on the orbital parameters and shrink the large errors on the predicted transit windows, enabling photometric monitoring to search for a transit signature. Here, we present the revised orbital parameters and the photometric coverage during a predicted transit window of HD168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a-priori transit probability (3.7%) from what is expected for a circular orbit (2.5%). The transit ephemeris was updated using refined orbital parameters from additional Keck-HIRES radial velocities. The photometry obtained at the 1 m telescope in Cerro Tololo Inter-American Observatory (CTIO) and the T8 0.8 m Automated Photometric Telescope (APT) at Fairborn Observatory achieved the necessary millimag precision. The expected change in flux (0.5%) for HD168443 was not observed during the predicted transit window, thus allowing us to rule out the transit and put tighter constrains on the orbital inclination of HD168443b. Additionally, we present the software used to analyze the CTIO data. Developed by the TERMS team, this IDL based package is a fast, precise, and easy to use program which has eliminated the need for external software and command line prompts by utilizing the functionality of a graphical user interface (GUI).

Precise Estimates of the Physical Parameters for the Exoplanet System HD 17156 Enabled by Hubble Space Telescope Fine Guidance Sensor Transit and Asteroseismic Observations

DEFF Research Database (Denmark)

Nutzman, Philip; Gilliland, Ronald L.; McCullough, Peter R.

2011-01-01

We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R sstarf = 0.07454 ± 0.00035, in......We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R sstarf = 0.07454 ± 0......-composition gas giant of the same mass and equilibrium temperature. For the three transits, we determine the times of mid-transit to a precision of 6.2 s, 7.6 s, and 6.9 s, and the transit times for HD 17156 do not show any significant departures from a constant period. The joint analysis of transit photometry...

EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

KAUST Repository

Piskorz, Danielle

2016-11-23

We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant\\'s atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth\\'s atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L-band observations and three epochs of Keck NIRSPEC K-band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross-correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40 +/- 15 km s(-1), a true mass of 1.02(-0.28)(+0.61) M-J, a nearly face-on orbital inclination of 15(-5)(+60), and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with 11 years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

A ground-based near-infrared emission spectrum of the exoplanet HD 189733b.

Science.gov (United States)

Swain, Mark R; Deroo, Pieter; Griffith, Caitlin A; Tinetti, Giovanna; Thatte, Azam; Vasisht, Gautam; Chen, Pin; Bouwman, Jeroen; Crossfield, Ian J; Angerhausen, Daniel; Afonso, Cristina; Henning, Thomas

2010-02-04

Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H(2)O), methane (CH(4)), carbon dioxide (CO(2)), and carbon monoxide (CO) have been detected in two hot Jupiters. These previous results relied on space-based telescopes that do not provide spectroscopic capability in the 2.4-5.2 microm spectral region. Here we report ground-based observations of the dayside emission spectrum for HD 189733b between 2.0-2.4 microm and 3.1-4.1 microm, where we find a bright emission feature. Where overlap with space-based instruments exists, our results are in excellent agreement with previous measurements. A feature at approximately 3.25 microm is unexpected and difficult to explain with models that assume local thermodynamic equilibrium (LTE) conditions at the 1 bar to 1 x 10(-6) bar pressures typically sampled by infrared measurements. The most likely explanation for this feature is that it arises from non-LTE emission from CH(4), similar to what is seen in the atmospheres of planets in our own Solar System. These results suggest that non-LTE effects may need to be considered when interpreting measurements of strongly irradiated exoplanets.

MULTI-EPOCH OBSERVATIONS OF HD 69830: HIGH-RESOLUTION SPECTROSCOPY AND LIMITS TO VARIABILITY

Energy Technology Data Exchange (ETDEWEB)

Beichman, C. A.; Tanner, A. M.; Bryden, G.; Akeson, R. L.; Ciardi, D. R. [NASA Exoplanet Science Institute, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91125 (United States); Lisse, C. M. [Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Boden, A. F. [Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125 (United States); Dodson-Robinson, S. E.; Salyk, C. [University of Texas, Astronomy Department, Austin, TX 78712 (United States); Wyatt, M. C., E-mail: chas@pop.jpl.nasa.gov [Institute of Astronomy, University of Cambridge, Cambridge, CB3 0HA (United Kingdom)

2011-12-10

The main-sequence solar-type star HD 69830 has an unusually large amount of dusty debris orbiting close to three planets found via the radial velocity technique. In order to explore the dynamical interaction between the dust and planets, we have performed multi-epoch photometry and spectroscopy of the system over several orbits of the outer dust. We find no evidence for changes in either the dust amount or its composition, with upper limits of 5%-7% (1{sigma} per spectral element) on the variability of the dust spectrum over 1 year, 3.3% (1{sigma}) on the broadband disk emission over 4 years, and 33% (1{sigma}) on the broadband disk emission over 24 years. Detailed modeling of the spectrum of the emitting dust indicates that the dust is located outside of the orbits of the three planets and has a composition similar to main-belt, C-type asteroids in our solar system. Additionally, we find no evidence for a wide variety of gas species associated with the dust. Our new higher signal-to-noise spectra do not confirm our previously claimed detection of H{sub 2}O ice leading to a firm conclusion that the debris can be associated with the break-up of one or more C-type asteroids formed in the dry, inner regions of the protoplanetary disk of the HD 69830 system. The modeling of the spectral energy distribution and high spatial resolution observations in the mid-infrared are consistent with a {approx}1 AU location for the emitting material.

RETIRED A STARS AND THEIR COMPANIONS. VI. A PAIR OF INTERACTING EXOPLANET PAIRS AROUND THE SUBGIANTS 24 SEXTANIS AND HD 200964

International Nuclear Information System (INIS)

Johnson, John Asher; Payne, Matthew; Ford, Eric B.; Howard, Andrew W.; Marcy, Geoffrey W.; Clubb, Kelsey I.; Bowler, Brendan P.; Henry, Gregory W.; Fischer, Debra A.; Brewer, John M.; Schwab, Christian; Reffert, Sabine; Lowe, Thomas B.

2011-01-01

We report radial velocity (RV) measurements of the G-type subgiants 24 Sextanis (= HD 90043) and HD 200964. Both are massive, evolved stars that exhibit periodic variations due to the presence of a pair of Jovian planets. Photometric monitoring with the T12 0.80 m APT at Fairborn Observatory demonstrates both stars to be constant in brightness to ≤0.002 mag, thus strengthening the planetary interpretation of the RV variations. Based on our dynamical analysis of the RV time series, 24 Sex b, c have orbital periods of 452.8 days and 883.0 days, corresponding to semimajor axes 1.333 AU and 2.08 AU, and minimum masses 1.99 M Jup and 0.86 M Jup , assuming a stellar mass M * = 1.54 M sun . HD 200964 b, c have orbital periods of 613.8 days and 825.0 days, corresponding to semimajor axes 1.601 AU and 1.95 AU, and minimum masses 1.99 M Jup and 0.90 M Jup , assuming M * = 1.44 M sun . We also carry out dynamical simulations to properly account for gravitational interactions between the planets. Most, if not all, of the dynamically stable solutions include crossing orbits, suggesting that each system is locked in a mean-motion resonance that prevents close encounters and provides long-term stability. The planets in the 24 Sex system likely have a period ratio near 2:1, while the HD 200964 system is even more tightly packed with a period ratio close to 4:3. However, we caution that further RV observations and more detailed dynamical modeling will be required to provide definitive and unique orbital solutions for both cases, and to determine whether the two systems are truly resonant.

Infrared absorption spectra of gaseous HD. II. Collision-induced fundamental band of HD in HD--Ne and HD--Ar mixtures at room temperature

International Nuclear Information System (INIS)

Prasad, R.D.G.; Reddy, S.P.

1976-01-01

The collision-induced infrared absorption spectra of the fundamental band of HD in binary mixtures of HD with Ne and Ar at room temperature have been studied with an absorption path length of 105.2 cm for different base densities of HD in the range 8--20 amagat and a number of total gas densities up to 175 amagat. The observed features of the profiles of the enhancement of absorption in these mixtures resemble closely those of the corresponding profiles of the fundamental band of H 2 in binary mixtures with Ne and Ar. The binary absorption coefficients of the band obtained from the measured integrated intensities are (1.84 +- 0.06) x 10 -35 and (4.41 +- 0.06) x 10 -35 cm 6 s -1 for HD--Ne and HD--Ar, respectively. The characteristic half-width parameters, delta/subd/ and delta/subc/ of the overlap transitions and delta/subq/ (and delta/subq//sub prime/) of the quadrupolar transitions, are obtained from an analysis of the profiles of the enhancement of absorption in both these mixtures. The quantity delta/subc/ which is the half-width of the intercollisional interference dip of the Q branch increases with the density of the perturbing gas Ne or Ar, and for HD--Ne it varies in a manner similar to that for HD--He as described in Paper I of this series

SPITZER IRAC SECONDARY ECLIPSE PHOTOMETRY OF THE TRANSITING EXTRASOLAR PLANET HAT-P-1b

International Nuclear Information System (INIS)

Todorov, Kamen; Deming, Drake; Harrington, Jospeph; Stevenson, Kevin B.; Bowman, William C.; Nymeyer, Sarah; Fortney, Jonathan J.; Bakos, Gaspar A.

2010-01-01

We report Spitzer/IRAC photometry of the transiting giant exoplanet HAT-P-1b during its secondary eclipse. This planet lies near the postulated boundary between the pM and pL-class of hot Jupiters, and is important as a test of models for temperature inversions in hot Jupiter atmospheres. We derive eclipse depths for HAT-P-1b, in units of the stellar flux, that are: 0.080% ± 0.008% [3.6 μm], 0.135% ± 0.022% [4.5 μm], 0.203% ± 0.031% [5.8 μm], and 0.238% ± 0.040% [8.0 μm]. These values are best fit using an atmosphere with a modest temperature inversion, intermediate between the archetype inverted atmosphere (HD 209458b) and a model without an inversion. The observations also suggest that this planet is radiating a large fraction of the available stellar irradiance on its dayside, with little available for redistribution by circulation. This planet has sometimes been speculated to be inflated by tidal dissipation, based on its large radius in discovery observations, and on a non-zero orbital eccentricity allowed by the radial velocity data. The timing of the secondary eclipse is very sensitive to orbital eccentricity, and we find that the central phase of the eclipse is 0.4999 ± 0.0005. The difference between the expected and observed phase indicates that the orbit is close to circular, with a 3σ limit of |e cos ω| < 0.002.

Low mass planets in protoplanetary disks with net vertical magnetic fields: the Planetary Wake and Gap Opening

OpenAIRE

Zhu, Zhaohuan; Stone, James M.; Rafikov, Roman R.

2013-01-01

We study wakes and gap opening by low mass planets in gaseous protoplanetary disks threaded by net vertical magnetic fields which drive magnetohydrodynamical (MHD) turbulence through the magnetorotational instabilty (MRI), using three dimensional simulations in the unstratified local shearing box approximation. The wakes, which are excited by the planets, are damped by shocks similar to the wake damping in inviscid hydrodynamic (HD) disks. Angular momentum deposition by shock damping opens ga...

Accurate effective temperatures of the metal-poor benchmark stars HD 140283, HD 122563, and HD 103095 from CHARA interferometry

Science.gov (United States)

Karovicova, I.; White, T. R.; Nordlander, T.; Lind, K.; Casagrande, L.; Ireland, M. J.; Huber, D.; Creevey, O.; Mourard, D.; Schaefer, G. H.; Gilmore, G.; Chiavassa, A.; Wittkowski, M.; Jofré, P.; Heiter, U.; Thévenin, F.; Asplund, M.

2018-03-01

Large stellar surveys of the Milky Way require validation with reference to a set of `benchmark' stars whose fundamental properties are well determined. For metal-poor benchmark stars, disagreement between spectroscopic and interferometric effective temperatures has called the reliability of the temperature scale into question. We present new interferometric measurements of three metal-poor benchmark stars, HD 140283, HD 122563, and HD 103095, from which we determine their effective temperatures. The angular sizes of all the stars were determined from observations with the PAVO beam combiner at visible wavelengths at the CHARA array, with additional observations of HD 103095 made with the VEGA instrument, also at the CHARA array. Together with photometrically derived bolometric fluxes, the angular diameters give a direct measurement of the effective temperature. For HD 140283, we find θLD = 0.324 ± 0.005 mas, Teff = 5787 ± 48 K; for HD 122563, θLD = 0.926 ± 0.011 mas, Teff = 4636 ± 37 K; and for HD 103095, θLD = 0.595 ± 0.007 mas, Teff = 5140 ± 49 K. Our temperatures for HD 140283 and HD 103095 are hotter than the previous interferometric measurements by 253 and 322 K, respectively. We find good agreement between our temperatures and recent spectroscopic and photometric estimates. We conclude some previous interferometric measurements have been affected by systematic uncertainties larger than their quoted errors.

Atmospheric mass-loss of extrasolar planets orbiting magnetically active host stars

Science.gov (United States)

Lalitha, Sairam; Schmitt, J. H. M. M.; Dash, Spandan

2018-06-01

Magnetic stellar activity of exoplanet hosts can lead to the production of large amounts of high-energy emission, which irradiates extrasolar planets, located in the immediate vicinity of such stars. This radiation is absorbed in the planets' upper atmospheres, which consequently heat up and evaporate, possibly leading to an irradiation-induced mass-loss. We present a study of the high-energy emission in the four magnetically active planet-bearing host stars, Kepler-63, Kepler-210, WASP-19, and HAT-P-11, based on new XMM-Newton observations. We find that the X-ray luminosities of these stars are rather high with orders of magnitude above the level of the active Sun. The total XUV irradiation of these planets is expected to be stronger than that of well-studied hot Jupiters. Using the estimated XUV luminosities as the energy input to the planetary atmospheres, we obtain upper limits for the total mass- loss in these hot Jupiters.

Three Temperate Neptunes Orbiting Nearby Stars

Science.gov (United States)

Fulton, Benjamin J.; Howard, Andrew W.; Weiss, Lauren M.; Sinukoff, Evan; Petigura, Erik A.; Isaacson, Howard; Hirsch, Lea; Marcy, Geoffrey W.; Henry, Gregory W.; Grunblatt, Samuel K.; Huber, Daniel; von Braun, Kaspar; Boyajian, Tabetha S.; Kane, Stephen R.; Wittrock, Justin; Horch, Elliott P.; Ciardi, David R.; Howell, Steve B.; Wright, Jason T.; Ford, Eric B.

2016-10-01

We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4 {M}\\oplus , a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6 {M}\\oplus and orbits interior to the previously known Jovian mass planet orbiting at 2.1 au. HD 164922 c has a semimajor axis of 0.34 au and an equilibrium temperature of 418 K. HD 143761 c orbits with a semimajor axis of 0.44 au, has a minimum mass of 25 ± 2 {M}\\oplus , and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of Hawai‘I, the University of California, and NASA.

The changing phases of extrasolar planet CoRoT-1b.

Science.gov (United States)

Snellen, Ignas A G; de Mooij, Ernst J W; Albrecht, Simon

2009-05-28

Hot Jupiters are a class of extrasolar planet that orbit their parent stars at very short distances. They are expected to be tidally locked, which can lead to a large temperature difference between their daysides and nightsides. Infrared observations of eclipsing systems have yielded dayside temperatures for a number of transiting planets. The day-night contrast of the transiting extrasolar planet HD 189733b was 'mapped' using infrared observations. It is expected that the contrast between the daysides and nightsides of hot Jupiters is much higher at visual wavelengths, shorter than that of the peak emission, and could be further enhanced by reflected stellar light. Here we report the analysis of optical photometric data obtained over 36 planetary orbits of the transiting hot Jupiter CoRoT-1b. The data are consistent with the nightside hemisphere of the planet being entirely black, with the dayside flux dominating the optical phase curve. This means that at optical wavelengths the planet's phase variation is just as we see it for the interior planets in the Solar System. The data allow for only a small fraction of reflected light, corresponding to a geometric albedo of <0.20.

On the Biohabitability of M-dwarf Planets

Science.gov (United States)

Wandel, A.

2018-04-01

The recent detection of Earth-sized planets in the habitable zone of Proxima Centauri, Trappist-1, and many other nearby M-type stars has led to speculations whether liquid water and life actually exist on these planets. To a large extent, the answer depends on their yet unknown atmospheres, which may, however, be within observational reach in the near future by JWST, ELT, and other planned telescopes. We consider the habitability of planets of M-type stars in the context of their atmospheric properties, heat transport, and irradiation. Instead of the traditional definition of the habitable zone, we define the biohabitable zone, where liquid water and complex organic molecules can survive on at least part of the planetary surface. The atmospheric impact on the temperature is quantified in terms of the heating factor (a combination of greenhouse heating, stellar irradiation, albedo, etc.) and heat redistribution (horizontal energy transport). We investigate the biohabitable domain (where planets can support surface liquid water and organics) in terms of these two factors. Our results suggest that planets orbiting M-type stars may have life-supporting temperatures, at least on part of their surface, for a wide range of atmospheric properties. We apply this analyses to Proxima Cen b and the Trappist-1 system. Finally, we discuss the implications for the search of biosignatures and demonstrate how they may be used to estimate the abundance of photosynthesis and biotic planets.

Late Thyroid Sequlae after Treatment of Hodgkin's Disease (HD)

International Nuclear Information System (INIS)

Abaza, A.

2012-01-01

To identify the late effects of radio- chemotherapy (CTH) on thyroid gland in long-term survivors (LTS) HD patients regularly attending the pediatric oncology clinic of National Cancer Institute (NCI), 42 LTS (33 males and 9 females) were studied, together with 26 newly-diagnosed (ND) HD patients (15 males and 11 females) and 28 healthy controls. During 3 years period, all patients subjected to through clinical history/ examination. Files of LTS were revised for date of diagnoses, original site (s), stage, histopathological subtypes and dose/ duration of therapy. Clinical examination was done with laying stress on neck examination for thyroid swelling and lymphadenopathy. Lab investigations include hormonal assay of thyroid and parathyroid (T3, T4, TSH, Thyroglobin, and parathormone). In LTS the mean age was 14.9±3.4 yrs. versus 9.5±3.7 yrs. in ND patients. In LTS, treatment modalities included radiotherapy (RT) alone (2.4%), CTH alone (26.2%) or combination chemo-RT (71.4%). The mean followup time was 7.47±2.19 yrs. The incidence of hyper-/hypo-thyroidism was significantly higher in LTS. High TSH was found only among patients who received chemo-RT (11/26) with thyroid irradiation (IR) in the whole neck field. Finally, the study documented that the hyper-/hypo-thyroidism was one of the long-term complication of radio-CTH in HD patients. Recommendations regarding the follow-up of therapy for HD were discussed. New strategies and evidence based surveillance of the long-term effects are needed for dealing with HD, especially in children

H-D exchange on natural aluminosilicates of orthosilicate group

International Nuclear Information System (INIS)

Markevich, S.V.; Kolesnikov, I.M.

1982-01-01

Experimental data are presented on the effect of aluminium ion coordination in the composition of polyhedrons on the capability of polyhedrons to change the reaction rate of H-D exchange (on the example of ethylene). It is shown that at temperature lower 400 deg C the rate of isotopic exchange reaction is low. Experimental results both for irradiated and non-irradiated minerals are presented. The conclusion is made that the increase of aluminosilicates activity under radiation is connected with the presence of (AlO 4 )-tetrahedrons in the system and change of their state. (AlO 5 ) and (AlO 6 )-polyhedrons are not activated with gamma rays

THE ANGLO-AUSTRALIAN PLANET SEARCH. XXI. A GAS-GIANT PLANET IN A ONE YEAR ORBIT AND THE HABITABILITY OF GAS-GIANT SATELLITES

International Nuclear Information System (INIS)

Tinney, C. G.; Wittenmyer, Robert A.; Bailey, Jeremy A.; Horner, J.; Butler, R. Paul; Jones, Hugh R. A.; O'Toole, Simon J.; Carter, Brad D.

2011-01-01

We have detected the Doppler signature of a gas-giant exoplanet orbiting the star HD 38283, in an eccentric orbit with a period of almost exactly one year (P = 363.2 ± 1.6 d, m sin i = 0.34 ± 0.02 M Jup , e = 0.41 ± 0.16). The detection of a planet with period very close to one year critically relied on year-round observation of this circumpolar star. Discovering a planet in a 1 AU orbit around a G dwarf star has prompted us to look more closely at the question of the habitability of the satellites of such planets. Regular satellites orbit all the giant planets in our solar system, suggesting that their formation is a natural by-product of the planet formation process. There is no reason for exomoon formation not to be similarly likely in exoplanetary systems. Moreover, our current understanding of that formation process does not preclude satellite formation in systems where gas giants undergo migration from their formation locations into the terrestrial planet habitable zone. Indeed, regular satellite formation and Type II migration are both linked to the clearing of a gap in the protoplanetary disk by a planet, and so may be inextricably linked. Migration would also multiply the chances of capturing both irregular satellites and Trojan companions sufficiently massive to be habitable. The habitability of such exomoons and exo-Trojans will critically depend on their mass, whether or not they host a magnetosphere, and (for the exomoon case) their orbital radius around the host exoplanet.

THE MASS OF HD 38529c FROM HUBBLE SPACE TELESCOPE ASTROMETRY AND HIGH-PRECISION RADIAL VELOCITIES

International Nuclear Information System (INIS)

Benedict, G. Fritz; McArthur, Barbara E.; Bean, Jacob L.; Barnes, Rory; Harrison, Thomas E.; Hatzes, Artie; Martioli, Eder; Nelan, Edmund P.

2010-01-01

Hubble Space Telescope Fine Guidance Sensor astrometric observations of the G4 IV star HD 38529 are combined with the results of the analysis of extensive ground-based radial velocity (RV) data to determine the mass of the outermost of two previously known companions. Our new RVs obtained with the Hobby-Eberly Telescope and velocities from the Carnegie-California group now span over 11 yr. With these data we obtain improved RV orbital elements for both the inner companion, HD 38529b, and the outer companion, HD 38529c. We identify a rotational period of HD 38529 (P rot = 31.65 ± 0fd17) with Fine Guidance Sensor photometry. The inferred star spot fraction is consistent with the remaining scatter in velocities being caused by spot-related stellar activity. We then model the combined astrometric and RV measurements to obtain the parallax, proper motion, perturbation period, perturbation inclination, and perturbation size due to HD 38529c. For HD 38529c we find P = 2136.1 ± 0.3 d, perturbation semimajor axis α = 1.05 ± 0.06 mas, and inclination i = 48. 0 3 ± 3. 0 7. Assuming a primary mass M * = 1.48 M sun , we obtain a companion mass M c = 17.6 +1.5 -1.2 M Jup , 3σ above a 13 M Jup deuterium burning, brown dwarf lower limit. Dynamical simulations incorporating this accurate mass for HD 38529c indicate that a near-Saturn mass planet could exist between the two known companions. We find weak evidence of an additional low amplitude signal that can be modeled as a planetary-mass (∼0.17 M Jup ) companion at P ∼194 days. Including this component in our modeling lowers the error of the mass determined for HD 38529c. Additional observations (RVs and/or Gaia astrometry) are required to validate an interpretation of HD 38529d as a planetary-mass companion. If confirmed, the resulting HD 38529 planetary system may be an example of a 'Packed Planetary System'.

Measuring Precise Radii of Giants Orbiting Giants to Distinguish Between Planet Evolution Models

Science.gov (United States)

Grunblatt, Samuel; Huber, Daniel; Lopez, Eric; Gaidos, Eric; Livingston, John

2017-10-01

Despite more than twenty years since the initial discovery of highly irradiated gas giant planets, the mechanism for planet inflation remains unknown. However, proposed planet inflation mechanisms can now be separated into two general classes: those which allow for post-main sequence planet inflation by direct irradiation from the host star, and those which only allow for slowed cooling of the planet over its lifetime. The recent discovery of two inflated warm Jupiters orbiting red giant stars with the NASA K2 Mission allows distinction between these two classes, but uncertainty in the planet radius blurs this distinction. Observing transits of these planets with the Spitzer Space Telescope would reduce stellar variability and thus planet radius uncertainties by approximately 50% relative to K2, allowing distinction between the two planet inflation model classes at a 3-sigma level. We propose to observe one transit of both known warm Jupiters orbiting red giant stars, K2-97b and EPIC228754001.01, to distinguish between planet model inflation classes and measure the planetary heating efficiency to 3-sigma precision. These systems are benchmarks for the upcoming NASA TESS Mission, which is predicted to discover an order of magnitude more red giant planet systems after launching next year.

INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE

Energy Technology Data Exchange (ETDEWEB)

Deming, Drake; Wilkins, Ashlee [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); McCullough, Peter; Crouzet, Nicolas [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Agol, Eric; Dobbs-Dixon, Ian [NASA Astrobiology Institute' s Virtual Planetary Laboratory (United States); Madhusudhan, Nikku [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Desert, Jean-Michel; Knutson, Heather A.; Line, Michael [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Haynes, Korey [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Magic, Zazralt [Max-Planck-Institut fuer Astrophysik, D-85741 Garching (Germany); Mandell, Avi M.; Clampin, Mark [NASA' s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ranjan, Sukrit; Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Seager, Sara, E-mail: ddeming@astro.umd.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

2013-09-10

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of {lambda}/{delta}{lambda} {approx} 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 {mu}m. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm{sup 2} g{sup -1} account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

Comparisons of amino acids, body constituents and antioxidative response between long-time HD and normal HD.

Science.gov (United States)

Torigoe, Akira; Sato, Emiko; Mori, Takefumi; Ieiri, Norio; Takahashi, Chika; Ishida, Yoko; Hotta, Osamu; Ito, Sadayoshi

2016-10-01

Introduction Oxidative stress is one of the main mediators of progression of chronic kidney diseases (CKD). Nuclear factor E2-related factor 2 (Nrf2) is the transcription factor of antioxidant and detoxifying enzymes and related proteins which play an important role in cellular defense. Long-time hemodialysis (HD) therapy (8 hours) has been considered to be more beneficial compared to normal HD therapy (4 hours). We investigated oxidative response related to Nrf2 in peripheral blood mononuclear cells (PBMCs) of long-time HD and normal HD patients. Methods Eight adult long-time HD therapy patients (44.5 ± 3.0 years) and 10 normal HD therapy patients (68.1 ± 2.7 years) were enrolled. PBMCs were isolated and processed for expression of Nrf2 and its related genes by qRT-PCR. Plasma indoxyl sulfate, amino acids, and body constituents were measured. Findings Plasma indoxyl sulfate was significantly low after long-time HD therapy compare to that of normal HD therapy. Although, skeletal muscle mass, lean body mass, mineral and protein were significantly decreased 2 months in normal HD patients, those in long-time HD patients were significantly increased after 2 months. Almost of amino acids were significantly decreased after HD therapy in both HD therapies. Plasma amino acids were significantly low in long-time HD patients compared to normal HD patients. In PBMCs, the expression of Nrf2 was significantly decreased and hemooxygenase-1 expression was significantly increased in long-time HD compared to normal HD. Conclusion These observations indicate the beneficial effects of in long-time HD in improving oxidative stress in patients. © 2016 International Society for Hemodialysis.

CO Gas Inside the Protoplanetary Disk Cavity in HD 142527: Disk Structure from ALMA

OpenAIRE

Perez, S.; Casassus, S.; Ménard, F.; Roman, P.; van der Plas, G.; Cieza, L.; Pinte, C.; Christiaens, Valentin; Hales, A. S.

2014-01-01

Inner cavities and annular gaps in circumstellar disks are possible signposts of giant planet formation. The young star HD 142527 hosts a massive protoplanetary disk with a large cavity that extends up to 140 AU from the central star, as seen in continuum images at infrared and millimeter wavelengths. Estimates of the survival of gas inside disk cavities are needed to discriminate between clearing scenarios. We present a spatially and spectrally resolved carbon monoxide isotopologue 2-1 line ...

THE EFFECT OF MASS LOSS ON THE TIDAL EVOLUTION OF EXTRASOLAR PLANET

International Nuclear Information System (INIS)

Guo, J. H.

2010-01-01

By combining mass loss and tidal evolution of close-in planets, we present a qualitative study on their tidal migrations. We incorporate mass loss in tidal evolution for planets with different masses and find that mass loss could interfere with tidal evolution. In an upper limit case (β = 3), a significant portion of mass may be evaporated in a long evolution timescale. Evidence of greater modification of the planets with an initial separation of about 0.1 AU than those with a = 0.15 AU can be found in this model. With the assumption of a large initial eccentricity, the planets with initial mass ≤1 M J and initial distance of about 0.1 AU could not survive. With the supposition of β = 1.1, we find that the loss process has an effect on the planets with low mass at a ∼ 0.05 AU. In both cases, the effect of evaporation on massive planets can be neglected. Also, heating efficiency and initial eccentricity have significant influence on tidal evolution. We find that even low heating efficiency and initial eccentricity have a significant effect on tidal evolution. Our analysis shows that evaporation on planets with different initial masses can accelerate (decelerate) the tidal evolution due to the increase (decrease) in tide of the planet (star). Consequently, the effect of evaporation cannot be neglected in evolutionary calculations of close-in planets. The physical parameters of HD 209458b can be fitted by our model.

Temperate Earth-sized planets transiting a nearby ultracool dwarf star.

Science.gov (United States)

Gillon, Michaël; Jehin, Emmanuël; Lederer, Susan M; Delrez, Laetitia; de Wit, Julien; Burdanov, Artem; Van Grootel, Valérie; Burgasser, Adam J; Triaud, Amaury H M J; Opitom, Cyrielle; Demory, Brice-Olivier; Sahu, Devendra K; Bardalez Gagliuffi, Daniella; Magain, Pierre; Queloz, Didier

2016-05-12

Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as 'ultracool dwarfs'. This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun. Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks, there should be a large but hitherto undetected population of terrestrial planets orbiting them--ranging from metal-rich Mercury-sized planets to more hospitable volatile-rich Earth-sized planets. Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star. Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system.

THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

International Nuclear Information System (INIS)

Knutson, Heather A.; Charbonneau, David; Cowan, Nicolas B.; Agol, Eric; Fortney, Jonathan J.; Showman, Adam P.; Henry, Gregory W.

2009-01-01

We monitor the star HD 149026 and its Saturn-mass planet at 8.0 μm over slightly more than half an orbit using the Infrared Array Camera on the Spitzer Space Telescope. We find an increase of 0.0227% ± 0.0066% (3.4σ significance) in the combined planet-star flux during this interval. The minimum flux from the planet is 45% ± 19% of the maximum planet flux, corresponding to a difference in brightness temperature of 480 ± 140 K between the two hemispheres. We derive a new secondary eclipse depth of 0.0411% ± 0.0076% in this band, corresponding to a dayside brightness temperature of 1440 ± 150 K. Our new secondary eclipse depth is half that of a previous measurement (3.0σ difference) in this same bandpass by Harrrington et al. We re-fit the Harrrington et al. data and obtain a comparably good fit with a smaller eclipse depth that is consistent with our new value. In contrast to earlier claims, our new eclipse depth suggests that this planet's dayside emission spectrum is relatively cool, with an 8 μm brightness temperature that is less than the maximum planet-wide equilibrium temperature. We measure the interval between the transit and secondary eclipse and find that that the secondary eclipse occurs 20.9 +7.2 -6.5 minutes earlier (2.9σ) than predicted for a circular orbit, a marginally significant result. This corresponds to ecos(ω) = -0.0079 +0.0027 -0.0025 , where e is the planet's orbital eccentricity and ω is the argument of pericenter.

LOW-MASS PLANETS IN PROTOPLANETARY DISKS WITH NET VERTICAL MAGNETIC FIELDS: THE PLANETARY WAKE AND GAP OPENING

Energy Technology Data Exchange (ETDEWEB)

Zhu Zhaohuan; Stone, James M.; Rafikov, Roman R., E-mail: zhzhu@astro.princeton.edu, E-mail: jstone@astro.princeton.edu, E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ, 08544 (United States)

2013-05-10

Some regions in protoplanetary disks are turbulent, while some regions are quiescent (e.g. the dead zone). In order to study how planets open gaps in both inviscid hydrodynamic disk (e.g. the dead zone) and the disk subject to magnetorotational instability (MRI), we carried out both shearing box two-dimensional inviscid hydrodynamical simulations and three-dimensional unstratified magnetohydrodynamical (MHD) simulations (having net vertical magnetic fields) with a planet at the box center. We found that, due to the nonlinear wave steepening, even a low mass planet can open gaps in both cases, in contradiction to the ''thermal criterion'' for gap opening. In order to understand if we can represent the MRI turbulent stress with the viscous {alpha} prescription for studying gap opening, we compare gap properties in MRI-turbulent disks to those in viscous HD disks having the same stress, and found that the same mass planet opens a significantly deeper and wider gap in net vertical flux MHD disks than in viscous HD disks. This difference arises due to the efficient magnetic field transport into the gap region in MRI disks, leading to a larger effective {alpha} within the gap. Thus, across the gap, the Maxwell stress profile is smoother than the gap density profile, and a deeper gap is needed for the Maxwell stress gradient to balance the planetary torque density. Comparison with previous results from net toroidal flux/zero flux MHD simulations indicates that the magnetic field geometry plays an important role in the gap opening process. We also found that long-lived density features (termed zonal flows) produced by the MRI can affect planet migration. Overall, our results suggest that gaps can be commonly produced by low mass planets in realistic protoplanetary disks, and caution the use of a constant {alpha}-viscosity to model gaps in protoplanetary disks.

LOW-MASS PLANETS IN PROTOPLANETARY DISKS WITH NET VERTICAL MAGNETIC FIELDS: THE PLANETARY WAKE AND GAP OPENING

International Nuclear Information System (INIS)

Zhu Zhaohuan; Stone, James M.; Rafikov, Roman R.

2013-01-01

Some regions in protoplanetary disks are turbulent, while some regions are quiescent (e.g. the dead zone). In order to study how planets open gaps in both inviscid hydrodynamic disk (e.g. the dead zone) and the disk subject to magnetorotational instability (MRI), we carried out both shearing box two-dimensional inviscid hydrodynamical simulations and three-dimensional unstratified magnetohydrodynamical (MHD) simulations (having net vertical magnetic fields) with a planet at the box center. We found that, due to the nonlinear wave steepening, even a low mass planet can open gaps in both cases, in contradiction to the ''thermal criterion'' for gap opening. In order to understand if we can represent the MRI turbulent stress with the viscous α prescription for studying gap opening, we compare gap properties in MRI-turbulent disks to those in viscous HD disks having the same stress, and found that the same mass planet opens a significantly deeper and wider gap in net vertical flux MHD disks than in viscous HD disks. This difference arises due to the efficient magnetic field transport into the gap region in MRI disks, leading to a larger effective α within the gap. Thus, across the gap, the Maxwell stress profile is smoother than the gap density profile, and a deeper gap is needed for the Maxwell stress gradient to balance the planetary torque density. Comparison with previous results from net toroidal flux/zero flux MHD simulations indicates that the magnetic field geometry plays an important role in the gap opening process. We also found that long-lived density features (termed zonal flows) produced by the MRI can affect planet migration. Overall, our results suggest that gaps can be commonly produced by low mass planets in realistic protoplanetary disks, and caution the use of a constant α-viscosity to model gaps in protoplanetary disks.

A Maximum Radius for Habitable Planets.

Science.gov (United States)

Alibert, Yann

2015-09-01

We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

EFFECT OF A STELLAR COMPANION ON THE MODELING OF HD 142527 INFRARED SED

OpenAIRE

Erick Nagel

2014-01-01

The discovery of a companion of the Herbig Ae/Be star HD 142527 motivates the study of the effect that it produces on the SED. The main change on the system configuration is the formation of a gap in the disk. Due to this change, a wall (outer edge of the gap), which is frontally illuminated by stellar radiation is formed. We present a model for the SED, considering all the components: a disk with two gaps (one produced by the stellar companion and the other by potential planets), three walls...

The HARPS search for southern extra-solar planets . XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone

Science.gov (United States)

Lo Curto, G.; Mayor, M.; Benz, W.; Bouchy, F.; Hébrard, G.; Lovis, C.; Moutou, C.; Naef, D.; Pepe, F.; Queloz, D.; Santos, N. C.; Segransan, D.; Udry, S.

2013-03-01

The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of ≈850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD 103774, HD 109271, and BD-061339. In this work we present the detection of five planets orbiting these stars, with msin (i) between 0.6 and 7 Neptune masses, four of which are in two multiple systems, comprising one super-Earth and one planet within the habitable zone of a late-type dwarf. Although for strategic reasons we chose efficiency over precision in this survey, we have the capability to detect planets down to the Neptune and super-Earth mass range as well as multiple systems, provided that enough data points are made available. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla (Chile), under the GTO program ID 072.C-0488 and the regular programs: 085.C-0019, 087.C-0831 and 089.C-0732. RV data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A59

The RoPES project with HARPS and HARPS-N. I. A system of super-Earths orbiting the moderately active K-dwarf HD 176986

Science.gov (United States)

Suárez Mascareño, A.; González Hernández, J. I.; Rebolo, R.; Velasco, S.; Toledo-Padrón, B.; Udry, S.; Motalebi, F.; Ségrasan, D.; Wyttenbach, A.; Mayor, M.; Pepe, F.; Lovis, C.; Santos, N. C.; Figueira, P.; Esposito, M.

2018-04-01

We report the discovery of a system of two super-Earths orbiting the moderately active K-dwarf HD 176986. This work is part of the RoPES RV program of G- and K-type stars, which combines radial velocities (RVs) from the HARPS and HARPS-N spectrographs to search for short-period terrestrial planets. HD 176986 b and c are super-Earth planets with masses of 5.74 and 9.18 M⊕, orbital periods of 6.49 and 16.82 days, and distances of 0.063 and 0.119 AU in orbits that are consistent with circular. The host star is a K2.5 dwarf, and despite its modest level of chromospheric activity (log10 (RHK' = -4.90 ± 0.04), it shows a complex activity pattern. Along with the discovery of the planets, we study the magnetic cycle and rotation of the star. HD 176986 proves to be suitable for testing the available RV analysis technique and further our understanding of stellar activity. Full Table A.1 is 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/612/A41Based on observations made with the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF - Fundación Galileo Galilei at the Roche de Los Muchachos Observatory of the Instituto de Astrofísica de Canarias (IAC); observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory (Chile).

Hubble space telescope near-ir transmission spectroscopy of the super-Earth HD 97658B

Energy Technology Data Exchange (ETDEWEB)

Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Dragomir, Diana [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Kreidberg, Laura; Bean, Jacob L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); McCullough, P. R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gillon, Michael [Institut d' Astrophysique et de Géophysique, Universiteé de Liége, Liége 1 (Belgium); Homeier, Derek [Centre de Recherche Astrophysique de Lyon, F-69364 Lyon (France); Howard, Andrew W., E-mail: hknutson@caltech.edu [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

2014-10-20

Recent results from the Kepler mission indicate that super-Earths (planets with masses between 1-10 times that of the Earth) are the most common kind of planet around nearby Sun-like stars. These planets have no direct solar system analogue, and are currently one of the least well-understood classes of extrasolar planets. Many super-Earths have average densities that are consistent with a broad range of bulk compositions, including both water-dominated worlds and rocky planets covered by a thick hydrogen and helium atmosphere. Measurements of the transmission spectra of these planets offer the opportunity to resolve this degeneracy by directly constraining the scale heights and corresponding mean molecular weights of their atmospheres. We present Hubble Space Telescope near-infrared spectroscopy of two transits of the newly discovered transiting super-Earth HD 97658b. We use the Wide Field Camera 3's (WFC3) scanning mode to measure the wavelength-dependent transit depth in 30 individual bandpasses. Our averaged differential transmission spectrum has a median 1σ uncertainty of 23 ppm in individual bins, making this the most precise observation of an exoplanetary transmission spectrum obtained with WFC3 to date. Our data are inconsistent with a cloud-free solar metallicity atmosphere at the 10σ level. They are consistent at the 0.4σ level with a flat line model, as well as effectively flat models corresponding to a metal-rich atmosphere or a solar metallicity atmosphere with a cloud or haze layer located at pressures of 10 mbar or higher.

Kepler planet-detection mission: introduction and first results.

Science.gov (United States)

Borucki, William J; Koch, David; Basri, Gibor; Batalha, Natalie; Brown, Timothy; Caldwell, Douglas; Caldwell, John; Christensen-Dalsgaard, Jørgen; Cochran, William D; DeVore, Edna; Dunham, Edward W; Dupree, Andrea K; Gautier, Thomas N; Geary, John C; Gilliland, Ronald; Gould, Alan; Howell, Steve B; Jenkins, Jon M; Kondo, Yoji; Latham, David W; Marcy, Geoffrey W; Meibom, Søren; Kjeldsen, Hans; Lissauer, Jack J; Monet, David G; Morrison, David; Sasselov, Dimitar; Tarter, Jill; Boss, Alan; Brownlee, Don; Owen, Toby; Buzasi, Derek; Charbonneau, David; Doyle, Laurance; Fortney, Jonathan; Ford, Eric B; Holman, Matthew J; Seager, Sara; Steffen, Jason H; Welsh, William F; Rowe, Jason; Anderson, Howard; Buchhave, Lars; Ciardi, David; Walkowicz, Lucianne; Sherry, William; Horch, Elliott; Isaacson, Howard; Everett, Mark E; Fischer, Debra; Torres, Guillermo; Johnson, John Asher; Endl, Michael; MacQueen, Phillip; Bryson, Stephen T; Dotson, Jessie; Haas, Michael; Kolodziejczak, Jeffrey; Van Cleve, Jeffrey; Chandrasekaran, Hema; Twicken, Joseph D; Quintana, Elisa V; Clarke, Bruce D; Allen, Christopher; Li, Jie; Wu, Haley; Tenenbaum, Peter; Verner, Ekaterina; Bruhweiler, Frederick; Barnes, Jason; Prsa, Andrej

2010-02-19

The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet's surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 days were discovered. The density of the Neptune-sized Kepler-4b is similar to that of Neptune and GJ 436b, even though the irradiation level is 800,000 times higher. Kepler-7b is one of the lowest-density planets (approximately 0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets.

Pro Tools HD

CERN Document Server

Camou, Edouard

2013-01-01

An easy-to-follow guide for using Pro Tools HD 11 effectively.This book is ideal for anyone who already uses ProTools and wants to learn more, or is new to Pro Tools HD and wants to use it effectively in their own audio workstations.

Hole-y Debris Disks, Batman! Where are the planets?

Science.gov (United States)

Bailey, V.; Meshkat, T.; Hinz, P.; Kenworthy, M.; Su, K. Y. L.

2014-03-01

Giant planets at wide separations are rare and direct imaging surveys are resource-intensive, so a cheaper marker for the presence of giant planets is desirable. One intriguing possibility is to use the effect of planets on their host stars' debris disks. Theoretical studies indicate giant planets can gravitationally carve sharp boundaries and gaps in their disks; this has been seen for HR 8799, β Pic, and tentatively for HD 95086 (Su et al. 2009, Lagrange et al. 2010, Moor et al. 2013). If more broadly demonstrated, this link could help guide target selection for next generation direct imaging surveys. Using Spitzer MIPS/IRS spectral energy distributions (SEDs), we identify several dozen systems with two-component and/or large inner cavity disks (aka Hole-y Debris Disks). With LBT/LBTI, VLT/NaCo, GeminiS/NICI, MMT/Clio and Magellan/Clio, we survey a subset these SEDselected targets (~20). In contrast to previous disk-selected planet surveys (e.g.: Janson et al. 2013, Wahhaj et al. 2013) we image primarily in the thermal IR (L'-band), where planet-to-star contrast is more favorable and background contaminants less numerous. Thus far, two of our survey targets host planet-mass companions, both of which were discovered in L'-band after they were unrecognized or undetectable in H-band. For each system in our sample set, we will investigate whether the known companions and/or companions below our detection threshold could be responsible for the disk architecture. Ultimately, we will increase our effective sample size by incorporating detection limits from surveys that have independently targeted some of our systems of interest. In this way we will refine the conditions under which disk SED-based target selection is likely to be useful and valid.

KEPLER PLANETS: A TALE OF EVAPORATION

International Nuclear Information System (INIS)

Owen, James E.; Wu, Yanqin

2013-01-01

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ⊕ . Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ⊕ and

KEPLER PLANETS: A TALE OF EVAPORATION

Energy Technology Data Exchange (ETDEWEB)

Owen, James E. [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Wu, Yanqin, E-mail: jowen@cita.utoronto.ca, E-mail: wu@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

2013-10-01

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R{sub ⊕}. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above

Gas Velocities Reveal Newly Born Planets in a Disk

Science.gov (United States)

Kohler, Susanna

2018-06-01

Occasionally, science comes together beautifully for a discovery and sometimes this happens for more than one team at once! Today we explore how two independent collaborations of scientists simultaneously found the very first kinematic evidence for young planets forming in a protoplanetary disk. Though they explored the same disk, the two teams in fact discovered different planets.Evidence for PlanetsALMAs view of the dust in the protoplanetary disk surrounding the young star HD 163296. Todays studies explore not the dust, but the gas of this disk. [ALMA (ESO/NAOJ/NRAO); A. Isella; B. Saxton (NRAO/AUI/NSF)]Over the past three decades, weve detected around 4,000 fully formed exoplanets. Much more elusive, however, are the young planets still in the early stages of formation; only a handful of these have been discovered. More observations of early-stage exoplanets are needed in order to understand how these worlds are born in dusty protoplanetary-disk environments, how they grow their atmospheres, and how they evolve.Recent observations by the Atacama Large Millimeter/submillimeter Array (ALMA) have produced stunning images of protoplanetary disks. The unprecedented resolution of these images reveals substructure in the form of gaps and rings, hinting at the presence of planets that orbit within the disk and clear out their paths as they move. But there are also non-planet mechanisms that could produce such substructure, like grain growth around ice lines, or hydrodynamic instabilities in the disk.How can we definitively determine whether there are nascent planets embedded in these disks? Direct direction of a point source in a dust gap would be a strong confirmation, but now we have the next best thing: kinematic evidence for planets, from the motion of a disks gas.Observations of carbon monoxide line emission at +1km/s from the systemic velocity (left) vs. the outcome of a computer simulation (right) in the Pinte et al. study. A visible kink occurs in the flow

Clouds on the hot Jupiter HD189733b: Constraints from the reflection spectrum

Energy Technology Data Exchange (ETDEWEB)

Barstow, J. K.; Aigrain, S.; Irwin, P. G. J.; Hackler, T.; Fletcher, L. N. [Department of Physics, University of Oxford, Oxford (United Kingdom); Lee, J. M. [Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich (Switzerland); Gibson, N. P., E-mail: jo.barstow@astro.ox.ac.uk [European Southern Observatory, D-85748 Garching bei München (Germany)

2014-05-10

The hot Jupiter HD 189733b is probably the best studied of the known extrasolar planets, with published transit and eclipse spectra covering the near UV to mid-IR range. Recent work on the transmission spectrum has shown clear evidence for the presence of clouds in its atmosphere, which significantly increases the model atmosphere parameter space that must be explored in order to fully characterize this planet. In this work, we apply the NEMESIS atmospheric retrieval code to the recently published HST/STIS reflection spectrum, and also to the dayside thermal emission spectrum in light of new Spitzer/IRAC measurements, as well as our own re-analysis of the HST/NICMOS data. We first use the STIS data to place some constraints on the nature of clouds on HD 189733b and explore solution degeneracy between different cloud properties and the abundance of Na in the atmosphere; as already noted in previous work, absorption due to Na plays a significant role in determining the shape of the reflection spectrum. We then perform a new retrieval of the temperature profile and abundances of H{sub 2}O, CO{sub 2}, CO, and CH{sub 4} from the dayside thermal emission spectrum. Finally, we investigate the effect of including cloud in the model on this retrieval process. We find that the current quality of data does not warrant the extra complexity introduced by including cloud in the model; however, future data are likely to be of sufficient resolution and signal-to-noise that a more complete model, including scattering particles, will be required.

A Decade of H α Transits for HD 189733 b: Stellar Activity versus Absorption in the Extended Atmosphere

Energy Technology Data Exchange (ETDEWEB)

Cauley, P. Wilson; Redfield, Seth [Wesleyan University, Astronomy Department, Van Vleck Observatory, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Jensen, Adam G., E-mail: pcauley@wesleyan.edu [University of Nebraska-Kearney, Department of Physics and Astronomy, 24011 11th Avenue, Kearney, NE 68849 (United States)

2017-05-01

HD 189733 b is one of the most well studied exoplanets due to its large transit depth and host star brightness. The focus on this object has produced a number of high-cadence transit observations using high-resolution optical spectrographs. Here we present an analysis of seven full H α transits of HD 189733 b using HARPS on the 3.6 meter La Silla telescope and HIRES on Keck I, taken over the course of nine years from 2006 to 2015. H α transmission signals are analyzed as a function of the stellar activity level, as measured using the normalized core flux of the Ca ii H and K lines. We find strong variations in the strength of the H α transmission spectrum from epoch to epoch. However, there is no clear trend between the Ca ii core emission and the strength of the in-transit H α signal, although the transit showing the largest absorption value also occurs when the star is the most active. We present simulations of the in-transit contrast effect and find that the planet must consistently transit active latitudes with very strong facular and plage emission regions in order to reproduce the observed line strengths. We also investigate the measured velocity centroids with models of planetary rotation and show that the small line profile velocities could be due to large velocities in the upper atmosphere of the planet. Overall, we find it more likely that the measured H α signals arise in the extended planetary atmosphere, although a better understanding of active region emission for active stars such as HD 189733 is needed.

IMAGING THE INNER AND OUTER GAPS OF THE PRE-TRANSITIONAL DISK OF HD 169142 AT 7 mm

Energy Technology Data Exchange (ETDEWEB)

Osorio, Mayra; Anglada, Guillem; Macías, Enrique; Gómez, José F.; Mayen-Gijon, Juan M. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Carrasco-González, Carlos; Rodríguez, Luis F.; D' Alessio, Paola [Centro de Radioastronomía y Astrofísica, UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán (Mexico); Torrelles, José M. [Institut de Ciències de l' Espai (CSIC)-Institut de Ciències del Cosmos (UB)/IEEC, Martí i Franquès 1, E-08028 Barcelona (Spain); Calvet, Nuria [Department of Astronomy, University of Michigan, 825 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Nagel, Erick [Departamento de Astronomía, Universidad de Guanajuato, Guanajuato, Gto 36240 (Mexico); Dent, William R. F. [ALMA SCO, Alonso de Córdova 3107, Vitacura, Santiago (Chile); Quanz, Sascha P.; Reggiani, Maddalena, E-mail: osorio@iaa.es [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)

2014-08-20

We present Very Large Array observations at 7 mm that trace the thermal emission of large dust grains in the HD 169142 protoplanetary disk. Our images show a ring of enhanced emission of radius ∼25-30 AU, whose inner region is devoid of detectable 7 mm emission. We interpret this ring as tracing the rim of an inner cavity or gap, possibly created by a planet or a substellar companion. The ring appears asymmetric, with the western part significantly brighter than the eastern one. This azimuthal asymmetry is reminiscent of the lopsided structures that are expected to be produced as a consequence of trapping of large dust grains. Our observations also reveal an outer annular gap at radii from ∼40 to ∼70 AU. Unlike other sources, the radii of the inner cavity, the ring, and the outer gap observed in the 7 mm images, which trace preferentially the distribution of large (millimeter/centimeter sized) dust grains, coincide with those obtained from a previous near-infrared polarimetric image, which traces scattered light from small (micron-sized) dust grains. We model the broadband spectral energy distribution and the 7 mm images to constrain the disk physical structure. From this modeling we infer the presence of a small (radius ∼0.6 AU) residual disk inside the central cavity, indicating that the HD 169142 disk is a pre-transitional disk. The distribution of dust in three annuli with gaps in between them suggests that the disk in HD 169142 is being disrupted by at least two planets or substellar objects.

Direct imaging of an ultracool substellar companion to the exoplanet host star HD 4113 A

Science.gov (United States)

Cheetham, A.; Ségransan, D.; Peretti, S.; Delisle, J.-B.; Hagelberg, J.; Beuzit, J.-L.; Forveille, T.; Marmier, M.; Udry, S.; Wildi, F.

2018-06-01

Using high-contrast imaging with the SPHERE instrument at the Very Large Telescope (VLT), we report the first images of a cold brown dwarf companion to the exoplanet host star HD 4113A. The brown dwarf HD 4113C is part of a complex dynamical system consisting of a giant planet, a stellar host, and a known wide M-dwarf companion. Its separation of 535 ± 3 mas and H-band contrast of 13.35 ± 0.10 mag correspond to a projected separation of 22 AU and an isochronal mass estimate of 36 ± 5 MJ based on COND models. The companion shows strong methane absorption, and through fitting an atmosphere model, we estimate a surface gravity of logg = 5 and an effective temperature of 500-600 K. A comparison of its spectrum with observed T dwarfs indicates a late-T spectral type, with a T9 object providing the best match. By combining the observed astrometry from the imaging data with 27 years of radial velocities, we use orbital fitting to constrain its orbital and physical parameters, as well as update those of the planet HD 4113A b, discovered by previous radial velocity measurements. The data suggest a dynamical mass of 66-4+5 MJ and moderate eccentricity of 0.44-0.07+0.08 for the brown dwarf. This mass estimate appears to contradict the isochronal estimate and that of objects with similar temperatures, which may be caused by the newly detected object being an unresolved binary brown dwarf system or the presence of an additional object in the system. Through dynamical simulations, we show that the planet may undergo strong Lidov-Kozai cycles, raising the possibility that it formed on a quasi-circular orbit and gained its currently observed high eccentricity (e 0.9) through interactions with the brown dwarf. Follow-up observations combining radial velocities, direct imaging, and Gaia astrometry will be crucial to precisely constrain the dynamical mass of the brown dwarf and allow for an in-depth comparison with evolutionary and atmosphere models. Based on observations

Changes in the metallicity of gas giant planets due to pebble accretion

Science.gov (United States)

Humphries, R. J.; Nayakshin, S.

2018-06-01

We run numerical simulations to study the accretion of gas and dust grains on to gas giant planets embedded into massive protoplanetary discs. The outcome is found to depend on the disc cooling rate, planet mass, grain size, and irradiative feedback from the planet. If radiative cooling is efficient, planets accrete both gas and pebbles rapidly, open a gap, and usually become massive brown dwarfs. In the inefficient cooling case, gas is too hot to accrete on to the planet but pebble accretion continues and the planets migrate inward rapidly. Radiative feedback from the planet tends to suppress gas accretion. Our simulations predict that metal enrichment of planets by dust grain accretion inversely correlates with the final planet mass, in accordance with the observed trend in the inferred bulk composition of Solar system and exosolar giant planets. To account for observations, however, as many as ˜30-50 per cent of the dust mass should be in the form of large grains.

Exploring the diversity of Jupiter-class planets.

Science.gov (United States)

Fletcher, Leigh N; Irwin, Patrick G J; Barstow, Joanna K; de Kok, Remco J; Lee, Jae-Min; Aigrain, Suzanne

2014-04-28

Of the 900+ confirmed exoplanets discovered since 1995 for which we have constraints on their mass (i.e. not including Kepler candidates), 75% have masses larger than Saturn (0.3 MJ), 53% are more massive than Jupiter and 67% are within 1 AU of their host stars. When Kepler candidates are included, Neptune-sized giant planets could form the majority of the planetary population. And yet the term 'hot Jupiter' fails to account for the incredible diversity of this class of astrophysical object, which exists on a continuum of giant planets from the cool jovians of our own Solar System to the highly irradiated, tidally locked hot roasters. We review theoretical expectations for the temperatures, molecular composition and cloud properties of hydrogen-dominated Jupiter-class objects under a variety of different conditions. We discuss the classification schemes for these Jupiter-class planets proposed to date, including the implications for our own Solar System giant planets and the pitfalls associated with compositional classification at this early stage of exoplanetary spectroscopy. We discuss the range of planetary types described by previous authors, accounting for (i) thermochemical equilibrium expectations for cloud condensation and favoured chemical stability fields; (ii) the metallicity and formation mechanism for these giant planets; (iii) the importance of optical absorbers for energy partitioning and the generation of a temperature inversion; (iv) the favoured photochemical pathways and expectations for minor species (e.g. saturated hydrocarbons and nitriles); (v) the unexpected presence of molecules owing to vertical mixing of species above their quench levels; and (vi) methods for energy and material redistribution throughout the atmosphere (e.g. away from the highly irradiated daysides of close-in giants). Finally, we discuss the benefits and potential flaws of retrieval techniques for establishing a family of atmospheric solutions that reproduce the

Multiple spiral patterns in the transitional disk of HD 100546

Science.gov (United States)

Boccaletti, A.; Pantin, E.; Lagrange, A.-M.; Augereau, J.-C.; Meheut, H.; Quanz, S. P.

2013-12-01

Context. Protoplanetary disks around young stars harbor many structures related to planetary formation. Of particular interest, spiral patterns were discovered among several of these disks and are expected to be the sign of gravitational instabilities leading to giant planet formation or gravitational perturbations caused by already existing planets. In this context, the star HD 100546 presents some specific characteristics with a complex gaseous and dusty disk that includes spirals, as well as a possible planet in formation. Aims: The objective of this study is to analyze high-contrast and high angular resolution images of this emblematic system to shed light on critical steps in planet formation. Methods: We retrieved archival images obtained at Gemini in the near IR (Ks band) with the instrument NICI and processed the data using an advanced high contrast imaging technique that takes advantage of the angular differential imaging. Results: These new images reveal the spiral pattern previously identified with Hubble Space Telescope (HST) with an unprecedented resolution, while the large-scale structure of the disk is mostly cancelled by the data processing. The single pattern to the southeast in HST images is now resolved into a multi-armed spiral pattern. Using two models of a gravitational perturber orbiting in a gaseous disk, we attempted to constrain the characteristics of this perturber, assuming that each spiral is independent, and drew qualitative conclusions. The non-detection of the northeast spiral pattern observed in HST allows putting a lower limit on the intensity ratio between the two sides of the disk, which if interpreted as forward scattering, yields a larger anisotropic scattering than is derived in the visible. Also, we find that the spirals are likely to be spatially resolved with a thickness of about 5-10 AU. Finally, we did not detect the candidate planet in formation recently discovered in the Lp band, with a mass upper limit of 16-18 MJ

The Transiting Exocomets in the HD 172555 System

Science.gov (United States)

Grady, C. A.; Brown, A.; Kamp, I.; Roberge, A.; Riviere-Marichalar, P.; Welsh, B.

2017-01-01

The Earth is thought to have formed dry, in a part of the Solar Nebula deficient in organic material, and to have acquired its organics and water through bombardment by minor bodies. Observations of this process in well-dated systems can provide insight into the probable origin and composition of the bombarding parent bodies. Transiting cometary activity has previously been reported in Ca II for the late-A member of the 241 Myr old Pictoris Moving Group member, HD 172555(Kiefer et al. 2014). We present HST STIS and COS spectra of HD 172555 demonstrating that the star has chromospheric emission and variable in falling gas features in transitions of silicon and carbon ions at times when no Fe II absorption is seen in the UV data, and no Ca II absorption is seen in contemporary optical spectra. The lack of CO absorption and stable gas absorption at the system velocity is consistent with the absence of a cold Kuiper belt analog (Riviere-Marichalar et al. 2012) in this system. The presence of infall in some species at one epoch and others at different epochs suggests that, like Pictoris, there may be more than one family of exocomets. If perturbed into star-grazing orbits by the same mechanism as for Pic, these data suggest that the wide planet frequency among A-early F stars in the PMG is at least 37.5, well above the frequency estimated for young moving groups independent of host star spectral type.

Direct Imaging Search for Extrasolar Planets in the Pleiades

Science.gov (United States)

Yamamoto, Kodai; Matsuo, Taro; Shibai, Hiroshi; Itoh, Yoichi; Konishi, Mihokko; Sudo, Jun; Tanii, Ryoko; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki;

Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates.

Science.gov (United States)

Wang, Congzheng; Hu, Song; Gao, Chunming; Feng, Chang

2018-02-08

In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field.

THE GEMINI/NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF PLANETS AROUND YOUNG MOVING GROUP STARS

Energy Technology Data Exchange (ETDEWEB)

Biller, Beth A.; Ftaclas, Christ [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69115 Heidelberg (Germany); Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hayward, Thomas L.; Hartung, Markus [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Males, Jared R.; Skemer, Andrew; Close, Laird M. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Chun, Mark [Institute for Astronomy, 640 North Aohoku Place, 209, Hilo, HI 96720-2700 (United States); Clarke, Fraser; Thatte, Niranjan [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road Flagstaff, AZ 86001 (United States); Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Boss, Alan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Lin, Douglas [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Alencar, Silvia H. P. [Departamento de Fisica-ICEx-Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 30270-901 Belo Horizonte, MG (Brazil); De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane [Universidade de Sao Paulo, IAG/USP, Departamento de Astronomia, Rua do Matao 1226, 05508-900 Sao Paulo, SP (Brazil); and others

2013-11-10

We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ΔH = 13.9 mag at 1'' in combined CH{sub 4} narrowband ADI+SDI mode and median contrasts of ΔH = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 M{sub Jup}, 16.4 ± 1.0 AU), CD–35 2722B (31 ± 8 M{sub Jup}, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M{sub ☉}, 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M{sub ☉}, 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

Limits on stellar companions to exoplanet host stars with eccentric planets

International Nuclear Information System (INIS)

Kane, Stephen R.; Hinkel, Natalie R.; Howell, Steve B.; Horch, Elliott P.; Feng, Ying; Wright, Jason T.; Ciardi, David R.; Everett, Mark E.; Howard, Andrew W.

2014-01-01

Though there are now many hundreds of confirmed exoplanets known, the binarity of exoplanet host stars is not well understood. This is particularly true of host stars that harbor a giant planet in a highly eccentric orbit since these are more likely to have had a dramatic dynamical history that transferred angular momentum to the planet. Here we present observations of four exoplanet host stars that utilize the excellent resolving power of the Differential Speckle Survey Instrument on the Gemini North telescope. Two of the stars are giants and two are dwarfs. Each star is host to a giant planet with an orbital eccentricity >0.5 and whose radial velocity (RV) data contain a trend in the residuals to the Keplerian orbit fit. These observations rule out stellar companions 4-8 mag fainter than the host star at passbands of 692 nm and 880 nm. The resolution and field of view of the instrument result in exclusion radii of 0.''05-1.''4, which excludes stellar companions within several AU of the host star in most cases. We further provide new RVs for the HD 4203 system that confirm that the linear trend previously observed in the residuals is due to an additional planet. These results place dynamical constraints on the source of the planet's eccentricities, place constraints on additional planetary companions, and inform the known distribution of multiplicity amongst exoplanet host stars.

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

International Nuclear Information System (INIS)

Ochiai, H.; Nagasawa, M.; Ida, S.

2014-01-01

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.

Small vs. large dust grains in transitional disks: do different cavity sizes indicate a planet?. SAO 206462 (HD 135344B) in polarized light with VLT/NACO

Science.gov (United States)

Garufi, A.; Quanz, S. P.; Avenhaus, H.; Buenzli, E.; Dominik, C.; Meru, F.; Meyer, M. R.; Pinilla, P.; Schmid, H. M.; Wolf, S.

2013-12-01

Context. Transitional disks represent a short stage of the evolution of circumstellar material. Studies of dust grains in these objects can provide pivotal information on the mechanisms of planet formation. Dissimilarities in the spatial distribution of small (μm-size) and large (mm-size) dust grains have recently been pointed out. Aims: Constraints on the small dust grains can be obtained by imaging the distribution of scattered light at near-infrared wavelengths. We aim at resolving structures in the surface layer of transitional disks (with particular emphasis on the inner 10-50 AU), thus increasing the scarce sample of high-resolution images of these objects. Methods: We obtained VLT/NACO near-IR high-resolution polarimetric differential imaging observations of SAO 206462 (HD 135344B). This technique allows one to image the polarized scattered light from the disk without any occulting mask and to reach an inner working angle of ~0.1″. Results: A face-on disk is detected in H and Ks bands between 0.1″ and 0.9″. No significant differences are seen between the H and Ks images. In addition to the spiral arms, these new data allow us to resolve for the first time an inner disk cavity for small dust grains. The cavity size (≃28 AU) is much smaller than what is inferred for large dust grains from (sub-)mm observations (39 to 50 AU). This discrepancy cannot be ascribed to any resolution effect. Conclusions: The interaction between the disk and potential orbiting companion(s) can explain both the spiral arm structure and the discrepant cavity sizes for small and large dust grains. One planet may be carving out the gas (and, thus, the small grains) at 28 AU, and generating a pressure bump at larger radii (39 AU), which holds back the large grains. We analytically estimate that, in this scenario, a single giant planet (with a mass between 5 and 15 MJ) at 17 to 20 AU from the star is consistent with the observed cavity sizes. Based on observations collected at the

Effects of Hd2 in the presence of the photoperiod-insensitive functional allele of Hd1 in rice

Directory of Open Access Journals (Sweden)

Zhen-Hua Zhang

2016-11-01

Full Text Available The role of photoperiod sensitivity (PS of flowering genes have become well recognized in rice, whereas little attention has been drawn to the non-PS component of these genes, especially to their influence on gene-by-gene interactions. Rice populations in which the photoperiod-sensitive allele at Hd1 has become insensitive to photoperiod but continued to affect heading date (HD were used in this study to fine-map a quantitative trait locus (QTL for HD and analyze its genetic relationship to Hd1. The QTL was delimitated to a 96.3-kb region on the distal end of the long arm of chromosome 7. Sequence comparison revealed that this QTL is identical to Hd2. In the near-isogenic line (NIL populations analyzed, Hd1 and Hd2 were shown to be photoperiod insensitive and have pleiotropic effects for HD, plant height and yield traits. The two genes were found to largely act additively in regulating HD and yield traits. The results indicate that non-PS components of flowering genes involved in photoperiod response play an important role in controlling flowering time and grain yield in rice, which should allow breeders to better manipulate pleiotropic genes for balancing adaptability and high-yielding accumulation.

SEARCHING FOR TROJAN ASTEROIDS IN THE HD 209458 SYSTEM: SPACE-BASED MOST PHOTOMETRY AND DYNAMICAL MODELING

International Nuclear Information System (INIS)

Moldovan, Reka; Matthews, Jaymie M.; Gladman, Brett; Bottke, William F.; Vokrouhlicky, David

2010-01-01

We have searched Microvariability and Oscillations of Stars (MOST) satellite photometry obtained in 2004, 2005, and 2007 of the solar-type star HD 209458 for Trojan asteroid swarms dynamically coupled with the system's transiting 'hot Jupiter' HD 209458b. Observations of the presence and nature of asteroids around other stars would provide unique constraints on migration models of exoplanetary systems. Our results set an upper limit on the optical depth of Trojans in the HD 209458 system that can be used to guide current and future searches of similar systems by upcoming missions. Using cross-correlation methods with artificial signals implanted in the data, we find that our detection limit corresponds to a relative Trojan transit depth of 1 x10 -4 , equivalent to ∼1 lunar mass of asteroids, assuming power-law Trojan size distributions similar to Jupiter's Trojans in our solar system. We confirm with dynamical interpretations that some asteroids could have migrated inward with the planet to its current orbit at 0.045 AU, and that the Yarkovsky effect is ineffective at eliminating objects of >1 m in size. However, using numerical models of collisional evolution we find that, due to high relative speeds in this confined Trojan environment, collisions destroy the vast majority of the asteroids in -7 .

ANISOTROPIC WINDS FROM CLOSE-IN EXTRASOLAR PLANETS

International Nuclear Information System (INIS)

Stone, James M.; Proga, Daniel

2009-01-01

We present two-dimensional hydrodynamic models of thermally driven winds from highly irradiated, close-in extrasolar planets. We adopt a very simple treatment of the radiative heating processes at the base of the wind, and instead focus on the differences between the properties of outflows in multidimensions in comparison to spherically symmetric models computed with the same methods. For hot (T ∼> 2 x 10 4 K) or highly ionized gas, we find that strong (supersonic) polar flows are formed above the planet surface which produce weak shocks and outflow on the night side. In comparison to a spherically symmetric wind with the same parameters, the sonic surface on the day side is much closer to the planet surface in multidimensions, and the total mass-loss rate is reduced by almost a factor of 4. We also compute the steady-state structure of interacting planetary and stellar winds. Both winds end in a termination shock, with a parabolic contact discontinuity which is draped over the planet separating the two shocked winds. The planetary wind termination shock and the sonic surface in the wind are well separated, so that the mass-loss rate from the planet is essentially unaffected. However, the confinement of the planetary wind to the small volume bounded by the contact discontinuity greatly enhances the column density close to the planet, which might be important for the interpretation of observations of absorption lines formed by gas surrounding transiting planets.

A detailed analysis of the HD 73526 2:1 resonant planetary system

Energy Technology Data Exchange (ETDEWEB)

Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G.; Salter, G. S.; Bailey, J.; Wright, D. [School of Physics, University of New South Wales, Sydney 2052 (Australia); Tan, Xianyu; Lee, Man Hoi [Department of Earth Sciences, The University of Hong Kong, Pokfulam Road (Hong Kong); Butler, R. P.; Arriagada, P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Carter, B. D. [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Jones, H. R. A. [University of Hertfordshire, Centre for Astrophysics Research, Science and Technology Research Institute, College Lane, AL10 9AB, Hatfield (United Kingdom); O' Toole, S. J. [Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670 (Australia); Crane, J. D.; Schectman, S. A.; Thompson, I. [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Minniti, D.; Diaz, M., E-mail: rob@phys.unsw.edu.au [Institute of Astrophysics, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

2014-01-10

We present six years of new radial velocity data from the Anglo-Australian and Magellan Telescopes on the HD 73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical (interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40° and 60°, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is no clearly preferred system inclination, the dynamical fit with i = 90° provides the best combination of goodness-of-fit and long-term dynamical stability.

Development of the HD-Teen Inventory.

Science.gov (United States)

Driessnack, Martha; Williams, Janet K; Barnette, J Jackson; Sparbel, Kathleen J; Paulsen, Jane S

2012-05-01

Adolescents, who have a parent with Huntington Disease (HD), not only are at genetic risk for HD but also are witness to its onset and devastating clinical progression as their parent declines. To date, no mechanism has been developed to direct health care providers to the atypical adolescent experiences of these teens. The purpose of this report is to describe the process of developing the HD-Teen Inventory clinical assessment tool. Forty-eight teens and young adults from 19 U.S. states participated in the evaluation of the HD-Teen Inventory tool. Following item analysis, the number of items was reduced and item frequency and reaction scales were combined, based on the strong correlation (r = .94). The resultant tool contains 15 inventory and 2 open-ended response items. The HD-Teen Inventory emerged as a more compact and efficient tool for identifying the most salient concerns of at-risk teens in HD families in research and/or clinical practice.

Spectroscopic characterization of extrasolar planets from ground-, space- and airborne-based observatories

Science.gov (United States)

Angerhausen, Daniel

2010-11-01

This thesis deals with techniques and results of observations of exoplanets from several platforms. In this work I present and then attempt solutions to particular issues and problems connected to ground- and space-based approaches to spectroscopic characterization of extrasolar planets. Furthermore, I present the future prospects of the airborne observatory, SOFIA, in this field of astronomy. The first part of this thesis covers results of an exploratory study to use near-infrared integral-field-spectroscopy to observe transiting extrasolar planets. I demonstrate how adaptive-optics assisted integral field spectroscopy compares with other spectroscopic techniques currently applied, foremost being slit spectroscopy. An advanced reduction method using elements of a spectral-differential decorrelation and optimized observation strategies is discussed. This concept was tested with K-Band time series observations of secondary eclipses of HD 209458b and HD 189733b obtained with the SINFONI at the Very Large Telescope (VLT), at spectral resolution of R~3000. In ground-based near infrared (NIR) observations, there is considerable likelihood of confusion between telluric absorption features and spectral features in the targeted object. I describe a detailed method that can cope with such confusion by a forward modelling approach employing Earth transmission models. In space-based transit spectroscopy with Hubble's NICMOS instrument, the main source of systematic noise is the perturbation in the instrument's configuration due to the near Earth orbital motion of the spacecraft. I present an extension to a pre-existing data analysis sequence that has allowed me to extract a NIR transmission spectrum of the hot-Neptune class planet GJ 436b from a data set that was highly corrupted by the above mentioned effects. Satisfyingly, I was able to obtain statistical consistency in spectra (acquired over a broad wavelength grid) over two distinct observing visits by HST. Earlier

Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates

Directory of Open Access Journals (Sweden)

Congzheng Wang

2018-02-01

Full Text Available In this work, we irradiated a high-definition (HD industrial camera based on a commercial-off-the-shelf (COTS CMOS image sensor (CIS with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB. The work is valuable and can provide suggestion for camera users in the radiation field.

PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS

International Nuclear Information System (INIS)

Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

2009-01-01

We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets. When planetesimals are included the outcome depends upon the total mass of the planets. For M tot ∼> 1 M J the final eccentricity distribution remains broad, whereas for M tot ∼ J a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits. We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks, and find that for high planet masses the majority of such systems evolve into resonance. A significant fraction leads to resonant chains that are planetary analogs of Jupiter's Galilean satellites. We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a ≅ 5-10 AU.

Survival of extrasolar giant planet moons in planet-planet scattering

Science.gov (United States)

CIAN HONG, YU; Lunine, Jonathan; Nicholson, Phillip; Raymond, Sean

2015-12-01

Planet-planet scattering is the best candidate mechanism for explaining the eccentricity distribution of exoplanets. Here we study the survival and dynamics of exomoons under strong perturbations during giant planet scattering. During close encounters, planets and moons exchange orbital angular momentum and energy. The most common outcomes are the destruction of moons by ejection from the system, collision with the planets and the star, and scattering of moons onto perturbed but still planet-bound orbits. A small percentage of interesting moons can remain bound to ejected (free-floating) planets or be captured by a different planet. Moons' survival rate is correlated with planet observables such as mass, semi-major axis, eccentricity and inclination, as well as the close encounter distance and the number of close encounters. In addition, moons' survival rate and dynamical outcomes are predetermined by the moons' initial semi-major axes. The survival rate drops quickly as moons' distances increase, but simulations predict a good chance of survival for the Galilean moons. Moons with different dynamical outcomes occupy different regions of orbital parameter space, which may enable the study of moons' past evolution. Potential effects of planet obliquity evolution caused by close encounters on the satellites’ stability and dynamics will be reported, as well as detailed and systematic studies of individual close encounter events.

Astrometry, radial velocity, and photometry: the HD 128311 system remixed with data from HST, HET, and APT

International Nuclear Information System (INIS)

McArthur, Barbara E.; Benedict, G. Fritz.; Cochran, William D.; Henry, Gregory W.; Hatzes, Artie; Harrison, Tom E.; Johns-Krull, Chris; Nelan, Ed

2014-01-01

We have used high-cadence radial velocity measurements from the Hobby-Eberly Telescope with published velocities from the Lick 3 m Shane Telescope, combined with astrometric data from the Hubble Space Telescope (HST) Fine Guidance Sensors to refine the orbital parameters of the HD 128311 system, and determine an inclination of 55.°95 ± 14.°55 and true mass of 3.789 −0.432 +0.924 M JUP for HD 128311 c. The combined radial velocity data also reveal a short period signal which could indicate a third planet in the system with an Msin i of 0.133 ± 0.005 M JUP or stellar phenomena. Photometry from the T12 0.8 m automatic photometric telescope at the Fairborn Observatory and HST are used to determine a photometric period close to, but not within the errors of the radial velocity signal. We performed a cross-correlation bisector analysis of the radial velocity data to look for correlations with the photometric period and found none. Dynamical integrations of the proposed system show long-term stability with the new orbital parameters of over 10 million years. Our new orbital elements do not support the claims of HD 128311 b and c being in mean motion resonance.

NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST /WFC3 SPECTROSCOPY

Energy Technology Data Exchange (ETDEWEB)

Line, Michael R. [NASA Ames Research Center, Moffet Field, CA 94035 (United States); Stevenson, Kevin B.; Bean, Jacob; Kreidberg, Laura [Department of Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 (United States); Desert, Jean-Michel [University of Amsterdam (Netherlands); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Madhusudhan, Nikku [Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom); Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States); Diamond-Lowe, Hannah [Department of Astronomy, Harvard Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States)

2016-12-01

The nature of the thermal structure of hot Jupiter atmospheres is one of the key questions raised by the characterization of transiting exoplanets over the past decade. There have been claims that many hot Jupiters exhibit atmospheric thermal inversions. However, these claims have been based on broadband photometry rather than the unambiguous identification of emission features with spectroscopy, and the chemical species that could cause the thermal inversions by absorbing stellar irradiation at high altitudes have not been identified despite extensive theoretical and observational effort. Here we present high-precision Hubble Space Telescope WFC3 observations of the dayside thermal emission spectrum of the hot Jupiter HD 209458b, which was the first exoplanet suggested to have a thermal inversion. In contrast to previous results for this planet, our observations detect water in absorption at 6.2 σ confidence. When combined with Spitzer photometry, the data are indicative of a monotonically decreasing temperature with pressure over the range of 1–0.001 bars at 7.7 σ confidence. We test the robustness of our results by exploring a variety of model assumptions, including the temperature profile parameterization, presence of a cloud, and choice of Spitzer data reduction. We also introduce a new analysis method to determine the elemental abundances from the spectrally retrieved mixing ratios with thermochemical self-consistency and find plausible abundances consistent with solar metallicity (0.06–10 × solar) and carbon-to-oxygen ratios less than unity. This work suggests that high-precision spectrophotometric results are required to robustly infer thermal structures and compositions of extrasolar planet atmospheres and to perform comparative exoplanetology.

The XUV environments of exoplanets from Jupiter-size to super-Earth

Science.gov (United States)

King, George W.; Wheatley, Peter J.; Salz, Michael; Bourrier, Vincent; Czesla, Stefan; Ehrenreich, David; Kirk, James; Lecavelier des Etangs, Alain; Louden, Tom; Schmitt, Jürgen; Schneider, P. Christian

2018-05-01

Planets that reside close-in to their host star are subject to intense high-energy irradiation. Extreme-ultraviolet (EUV) and X-ray radiation (together, XUV) is thought to drive mass loss from planets with volatile envelopes. We present XMM-Newton observations of six nearby stars hosting transiting planets in tight orbits (with orbital period, Porb < 10 d), wherein we characterise the XUV emission from the stars and subsequent irradiation levels at the planets. In order to reconstruct the unobservable EUV emission, we derive a new set of relations from Solar TIMED/SEE data that are applicable to the standard bands of the current generation of X-ray instruments. From our sample, WASP-80b and HD 149026b experience the highest irradiation level, but HAT-P-11b is probably the best candidate for Ly α evaporation investigations because of the system's proximity to the Solar System. The four smallest planets have likely lost a greater percentage of their mass over their lives than their larger counterparts. We also detect the transit of WASP-80b in the near ultraviolet with the Optical Monitor on XMM-Newton

Coronary heart disease mortality after irradiation for Hodgkin's disease

International Nuclear Information System (INIS)

Boivin, J.F.; Hutchison, G.B.

1982-01-01

The authors conducted a study designed to evaluate the hypothesis that irradiation to the heart in the treatment for Hodgkin's disease (HD) is associated with increased coronary heart disease (CHD) mortality. This report describes 957 patients diagnosed with HD in 1942-75 and analyzes follow-up findings through December 1977. Twenty-five coronary heart disease deaths have been observed, and 4258.2 person-years of experience at risk have been accrued. The relative death rate (RDR), defined as the CHD mortality for heart-irradiated subjects divided by the mortality for nonirradiated subjects, was estimated. After adjustment for the effect of interval of observation, age, stage, and class, the RDR estimate is 1.5 but does not differ significantly from unit

Study on diagnosis of HD

International Nuclear Information System (INIS)

Chen Shuran; Yang Yumei; Zhang Guangli

1994-01-01

The study suggests a three-step diagnostic method for diagnosing HD. The first step is to make TgA, TmA examination; the second step is to make differential diagnosis for the cases of negative TgA, TmA through FNAB examination; the third step is to make TgA, TmA and FNAB examination for dynamic observation of controversial cases left over in the former two steps to achieve accurate diagnosis. Differential diagnosis has been made with the method in 87 cases of HD (clinical diagnosis only). The result shows that 7 cases have been diagnosed as thyropathy through comprehensive evaluation; definite diagnosis of HD has been made in 62 cases through TgA, TmA and in 77 cases through FNAB; 3 cases of negative TgA and TmA failed to accept FNAB examination, and were later diagnosed as HD through operation pathology or clinical treatment

HD5980

Science.gov (United States)

Koenigsberger, C.

HD5980 is a multiple system containing at least 3 very massive and luminous stars. Located in the Small Magellanic Cloud, it is an ideal system for studying the massive star structure and evolutionary processes in low-metallicity environments. Intensely observed over the past few decades, HD5980 is a treasure trove of information on stellar wind structure, on wind-wind collisions and on the formation of wind-blown circumstellar structures. In addition, its characteristics suggest that the eclipsing WR+LBV stars of the system are the product of quasihomogeneous chemical evolution, thus making them candidate pair production supernovae or GRB progenitors. This paper summarizes some of the outstanding results derived from half a century of observations and recent theoretical studies.

MASS-RADIUS RELATIONSHIPS FOR VERY LOW MASS GASEOUS PLANETS

International Nuclear Information System (INIS)

Batygin, Konstantin; Stevenson, David J.

2013-01-01

Recently, the Kepler spacecraft has detected a sizable aggregate of objects, characterized by giant-planet-like radii and modest levels of stellar irradiation. With the exception of a handful of objects, the physical nature, and specifically the average densities, of these bodies remain unknown. Here, we propose that the detected giant planet radii may partially belong to planets somewhat less massive than Uranus and Neptune. Accordingly, in this work, we seek to identify a physically sound upper limit to planetary radii at low masses and moderate equilibrium temperatures. As a guiding example, we analyze the interior structure of the Neptune-mass planet Kepler-30d and show that it is acutely deficient in heavy elements, especially compared with its solar system counterparts. Subsequently, we perform numerical simulations of planetary thermal evolution and in agreement with previous studies, show that generally, 10-20 M ⊕ , multi-billion year old planets, composed of high density cores and extended H/He envelopes can have radii that firmly reside in the giant planet range. We subject our results to stability criteria based on extreme ultraviolet radiation, as well as Roche-lobe overflow driven mass-loss and construct mass-radius relationships for the considered objects. We conclude by discussing observational avenues that may be used to confirm or repudiate the existence of putative low mass, gas-dominated planets.

VizieR Online Data Catalog: Radial velocities for the HD 3167 system (Christiansen+, 2017)

Science.gov (United States)

Christiansen, J. L.; Vanderburg, A.; Burt, J.; Fulton, B. J.; Batygin, K.; Benneke, B.; Brewer, J. M.; Charbonneau, D.; Ciardi, D. R.; Cameron, A. C.; Coughlin, J. L.; Crossfield, I. J. M.; Dressing, C.; Greene, T. P.; Howard, A. W.; Latham, D. W.; Molinari, E.; Mortier, A.; Mullally, F.; Pepe, F.; Rice, K.; Sinukoff, E.; Sozzetti, A.; Thompson, S. E.; Udry, S.; Vogt, S. S.; Barman, T. S.; Batalha, N. E.; Bouchy, F.; Buchhave, L. A.; Butler, R. P.; Cosentino, R.; Dupuy, T. J.; Ehrenreich, D.; Fiorenzano, A.; Hansen, B. M. S.; Henning, T.; Hirsch, L.; Holden, B. P.; Isaacson, H. T.; Johnson, J. A.; Knutson, H. A.; Kosiarek, M.; Lopez-Morales, M.; Lovis, C.; Malavolta, L.; Mayor, M.; Micela, G.; Motalebi, F.; Petigura, E.; Phillips, D. F.; Piotto, G.; Rogers, L. A.; Sasselov, D.; Schlieder, J. E.; Segransan, D.; Watson, C. A.; Weiss, L. M.

2018-06-01

The final data set includes observations obtained with Keck/HIRES, Automated Planet Finder (APF)/Levy, and HARPS-N. Our observational setup for both Keck/HIRES and the APF/Levy was essentially identical to those described in Fulton et al. (2016, J/ApJ/830/46) and Burt et al. (2014ApJ...789..114B). We collected a total of 60 RV measurements using Keck/HIRES (Vogt et al. 1994SPIE.2198..362V), and 116 measurements using the Levy Spectrograph on the APF (Radovan et al. 2014SPIE.9145E..2BR; Vogt et al. 2014PASP..126..359V) at Lick Observatory between 2016 July 7 and 2016 December 2. We also observed HD 3167 with the HARPS-N spectrograph (Cosentino et al. 2012SPIE.8446E..1VC) located at the 3.58 m Telescopio Nazionale Galileo on the island of La Palma, Spain. HARPS-N is a stabilized spectrograph designed for precise RV measurements. We observed HD 3167 76 times between 2016 July 7 (independently beginning the same night as the HIRES/APF campaign) and 2016 December 7, obtaining high-resolution optical spectra with a spectral resolving power of R=115000. (1 data file).

Ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

Science.gov (United States)

Kislyakova, Kristina; Pilat-Lohinger, Elke; Funk, Barbara; Lammer, Helmut; Fossati, Luca; Eggl, Siegfried; Schwarz, Richard; Boudyada, Mohammed; Erkaev, Nikolai

2017-04-01

We suggest an additional possible plasma source in the WASP-12 and HD189733b systems to explain part of the phenomena observed in ultraviolet (UV) light curves during planetary transits. In the proposed scenario, material originates from the molten surface of Trojan satellites on orbits near the Lagrange points L4 and L5. We show that the temperature at the orbital location of WASP-12b is high enough to melt the surface of rocky Trojans and to form shallow lava oceans on them. At the orbital distance of WASP-12b, this leads to the release of elements such as Mg and Ca, which are expected to surround the system. The predicted Mg and Ca outgassing rates from two Io-sized WASP-12b Trojans are ≈ 2.2 × 1027 s-1 and ≈ 2.2 × 1026 s-1, respectively. Trojan outgassing can lead to the observed lack of emission in MgII h&k and CaII H&K line cores of WASP-12. For HD 189733b, the mechanism is only marginally possible due to the lower temperature. The early ingress of HD 189733b observed in the far-UV (FUV) CII doublet couldn't be explained by this mechanism due to absence of carbon within elements outgassed by molten lava. We investigate the long-term stability region of WASP-12b and HD 189733b in case of planar and inclined motion of these satellites and show that unlike the classical exomoons orbiting the planet, Io-sized Trojans can be stable for the whole systems life time.

HAT-P-49b: a 1.7 M {sub J} planet transiting a bright 1.5 M {sub ☉} F-star

Energy Technology Data Exchange (ETDEWEB)

Bieryla, A.; Latham, D. W.; Buchhave, L. A.; Béky, B.; Falco, E.; Torres, G.; Noyes, R. W.; Berlind, P.; Calkins, M. C.; Esquerdo, G. A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Hartman, J. D.; Bakos, G. Á.; Bhatti, W.; Csubry, Z.; Penev, K.; De Val-Borro, M. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Kovács, G. [Konkoly Observatory, Budapest 1121 (Hungary); Boisse, I. [Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Lázár, J.; Papp, I., E-mail: abieryla@cfa.harvard.edu, E-mail: gbakos@astro.princeton.edu [Hungarian Astronomical Association (HAA), Budapest 1461 (Hungary); and others

2014-04-01

We report the discovery of the transiting extrasolar planet HAT-P-49b. The planet transits the bright (V = 10.3) slightly evolved F-star HD 340099 with a mass of 1.54 M {sub ☉} and a radius of 1.83 R {sub ☉}. HAT-P-49b is orbiting one of the 25 brightest stars to host a transiting planet which makes this a favorable candidate for detailed follow-up. This system is an especially strong target for Rossiter-McLaughlin follow-up due to the host star's fast rotation, 16 km s{sup –1}. The planetary companion has a period of 2.6915 days, mass of 1.73 M {sub J}, and radius of 1.41 R {sub J}. The planetary characteristics are consistent with that of a classical hot Jupiter but we note that this is the fourth most massive star to host a transiting planet with both M{sub p} and R{sub p} well determined.

ACCRETION KINEMATICS THROUGH THE WARPED TRANSITION DISK IN HD 142527 FROM RESOLVED CO(6–5) OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Casassus, S.; Marino, S.; Pérez, S.; Plas, G. van der; Christiaens, V.; Montesinos, Matías [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Roman, P.; Dunhill, A.; Cuadra, J.; Cieza, L.; Moral, Victor [Millennium Nucleus “Protoplanetary Disks,” Chile (Chile); Armitage, P. J. [JILA, University of Colorado and NIST, UCB 440, Boulder, CO 80309 (United States); Wootten, A., E-mail: scasassus@u.uchile.cl [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)

2015-10-01

The finding of residual gas in the large central cavity of the HD 142527 disk motivates questions regarding the origin of its non-Keplerian kinematics and possible connections with planet formation. We aim to understand the physical structure that underlies the intra-cavity gaseous flows, guided by new molecular-line data in CO(6–5) with unprecedented angular resolutions. Given the warped structure inferred from the identification of scattered-light shadows cast on the outer disk, the kinematics are consistent, to first order, with axisymmetric accretion onto the inner disk occurring at all azimuths. A steady-state accretion profile, fixed at the stellar accretion rate, explains the depth of the cavity as traced in CO isotopologues. The abrupt warp and evidence for near free-fall radial flows in HD 142527 resemble theoretical models for disk tearing, which could be driven by the reported low-mass companion, whose orbit may be contained in the plane of the inner disk. The companion’s high inclination with respect to the massive outer disk could drive Kozai oscillations over long timescales; high-eccentricity periods may perhaps account for the large cavity. While shadowing by the tilted disk could imprint an azimuthal modulation in the molecular-line maps, further observations are required to ascertain the significance of azimuthal structure in the density field inside the cavity of HD 142527.

The Danish HD Registrya nationwide family registry of HD families in Denmark

DEFF Research Database (Denmark)

Gilling, M.; Budtz-Jorgensen, E.; Boonen, S. E.

2017-01-01

-8:100 000. 1451 individuals in the DHR had the size of the HTT CAG repeat determined of which 975 had 36 CAG repeats or more (mean ± SD: 43,5 ± 4,8). Two unrelated individuals were compound heterozygous for alleles ≥36 CAGs, and 60 individuals from 34 independent families carried an intermediate allele.......The Danish Huntington's Disease Registry (DHR) is a nationwide family registry comprising 14 245 individuals from 445 Huntington's disease (HD) families of which the largest family includes 845 individuals in 8 generations. 1136 DNA and/or blood samples and 18 fibroblast cultures are stored...... in a local biobank. The birthplace of the oldest HD carrier in each of the 261 families of Danish origin was unevenly distributed across Denmark with a high number of families in the middle part of the peninsula Jutland and in Copenhagen, the capital. The prevalence of HD in Denmark was calculated to be 5...

Spectroscopic studies of O-type binaries. IV. HD 165052 and Hd 167771

International Nuclear Information System (INIS)

Morrison, N.D.; Conti, P.S.

1978-01-01

HD 165052, O6.5 V, and HD 167771, 07.5 III ((f)), are double-lined binaries with periods of six and four days, respectively, and velocity semiamplitudes near 100 km s -1 . In our spectroscopic orbital analysis, we investigated the effect of correcting the measured radial velocities for pair blending. The derived velocity amplitudes are increased by roughly 7%, and hence the minimum masses increase by 20%--255. The raw data lead to minimum masses, m sin 3 i, between 2 and 3 mD/sub sun/. Since normal O stars are thought to have masses greater than 20 m/sub sun/, the orbits must be highly inclined to the line of sight. From the luminosities and effective temperatures we derived stellar radii. For HD 167771, the requirement that neither component over fill it Roche lobe implies that each has a mass in the neighborhood of 30m/sub sun/ or larger

Distillation of hydrogen isotopes for polarized HD targets

Energy Technology Data Exchange (ETDEWEB)

Ohta, T., E-mail: takeshi@rcnp.osaka-u.ac.jp [Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567-0047 (Japan); Bouchigny, S. [IN2P3, Institut de Physique Nucleaire, F-91406 Orsay (France); CEA LIST, BP6-92265 Fontenay-aux-Roses, CEDEX (France); Didelez, J.-P. [IN2P3, Institut de Physique Nucleaire, F-91406 Orsay (France); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567-0047 (Japan); Fukuda, K. [Kansai University of Nursing and Health Sciences, Shizuki Awaji 656-2131 (Japan); Kohri, H.; Kunimatsu, T.; Morisaki, C.; Ono, S. [Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567-0047 (Japan); Rouille, G. [IN2P3, Institut de Physique Nucleaire, F-91406 Orsay (France); Tanaka, M. [Kobe Tokiwa University, Ohtani-cho 2-6-2, Nagata, Kobe 653-0838 (Japan); Ueda, K.; Uraki, M.; Utsuro, M. [Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567-0047 (Japan); Wang, S.Y. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Department of Physics, National Kaohsiung Normal University, Kaohsiung 824, Taiwan (China); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 567-0047 (Japan)

2012-02-01

We have developed a new cryogenic distillation system to purify Hydrogen-Deuteride (HD) gas for polarized HD targets in LEPS experiments at SPring-8. A small amount of ortho-H{sub 2} ({approx}0.01%) in the HD gas plays an important role in efficiently polarizing the HD target. Since there are 1-5% impurities of H{sub 2} and D{sub 2} in commercially available HD gases, it is necessary to purify the HD gas up to {approx}99.99%. The distillation system is equipped with a cryogenic distillation unit filled with many small stainless steel cells called 'Heli-pack'. The distillation unit consists of a condenser part, a rectification part, and a reboiler part. The unit is kept at the temperature of 17-21 K. The Heli-pack has a large surface area that makes a good contact between gases and liquids. An amount of 5.2 mol of commercial HD gas is fed into the distillation unit. Three trials were carried out to purify the HD gas by changing temperatures (17.5 K and 20.5 K) and gas extraction speeds (1.3 ml/min and 5.2 ml/min). The extracted gas was analyzed using a gas analyzer system combining a quadrupole mass spectrometer with a gas chromatograph. One mol of HD gas with a purity better than 99.99% has been successfully obtained for the first time. The effective NTP (Number of Theoretical Plates), which is an indication of the distillation performances, is obtained to be 37.2{+-}0.6. This value is in good agreement with a designed value of 37.9. The HD target is expected to be efficiently polarized under a well-controlled condition by adding an optimal amount of ortho-H{sub 2} to the purified HD gas.

Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities

Science.gov (United States)

Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.

2015-01-01

Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

Fundamental parameters of massive stars in multiple systems: The cases of HD 17505A and HD 206267A

Science.gov (United States)

Raucq, F.; Rauw, G.; Mahy, L.; Simón-Díaz, S.

2018-06-01

Context. Many massive stars are part of binary or higher multiplicity systems. The present work focusses on two higher multiplicity systems: HD 17505A and HD 206267A. Aims: Determining the fundamental parameters of the components of the inner binary of these systems is mandatory to quantify the impact of binary or triple interactions on their evolution. Methods: We analysed high-resolution optical spectra to determine new orbital solutions of the inner binary systems. After subtracting the spectrum of the tertiary component, a spectral disentangling code was applied to reconstruct the individual spectra of the primary and secondary. We then analysed these spectra with the non-LTE model atmosphere code CMFGEN to establish the stellar parameters and the CNO abundances of these stars. Results: The inner binaries of these systems have eccentric orbits with e 0.13 despite their relatively short orbital periods of 8.6 and 3.7 days for HD 17505Aa and HD 206267Aa, respectively. Slight modifications of the CNO abundances are found in both components of each system. The components of HD 17505Aa are both well inside their Roche lobe, whilst the primary of HD 206267Aa nearly fills its Roche lobe around periastron passage. Whilst the rotation of the primary of HD 206267Aa is in pseudo-synchronization with the orbital motion, the secondary displays a rotation rate that is higher. Conclusions: The CNO abundances and properties of HD 17505Aa can be explained by single star evolutionary models accounting for the effects of rotation, suggesting that this system has not yet experienced binary interaction. The properties of HD 206267Aa suggest that some intermittent binary interaction might have taken place during periastron passages, but is apparently not operating anymore. Based on observations collected with the TIGRE telescope (La Luz, Mexico), the 1.93 m telescope at Observatoire de Haute Provence (France), the Nordic Optical Telescope at the Observatorio del Roque de los

Energy Dissipation in the Upper Atmospheres of TRAPPIST-1 Planets

Science.gov (United States)

Cohen, Ofer; Glocer, Alex; Garraffo, Cecilia; Drake, Jeremy J.; Bell, Jared M.

2018-03-01

We present a method to quantify the upper limit of the energy transmitted from the intense stellar wind to the upper atmospheres of three of the TRAPPIST-1 planets (e, f, and g). We use a formalism that treats the system as two electromagnetic regions, where the efficiency of the energy transmission between one region (the stellar wind at the planetary orbits) to the other (the planetary ionospheres) depends on the relation between the conductances and impedances of the two regions. Since the energy flux of the stellar wind is very high at these planetary orbits, we find that for the case of high transmission efficiency (when the conductances and impedances are close in magnitude), the energy dissipation in the upper planetary atmospheres is also very large. On average, the Ohmic energy can reach 0.5–1 W m‑2, about 1% of the stellar irradiance and 5–15 times the EUV irradiance. Here, using constant values for the ionospheric conductance, we demonstrate that the stellar wind energy could potentially drive large atmospheric heating in terrestrial planets, as well as in hot Jupiters. More detailed calculations are needed to assess the ionospheric conductance and to determine more accurately the amount of heating the stellar wind can drive in close-orbit planets.

HD 169142 in the eyes of ZIMPOL/SPHERE

Science.gov (United States)

Bertrang, G. H.-M.; Avenhaus, H.; Casassus, S.; Montesinos, M.; Kirchschlager, F.; Perez, S.; Cieza, L.; Wolf, S.

2018-03-01

We present new data of the protoplanetary disc surrounding the Herbig Ae/Be star HD 169142 obtained in the very broad-band (VBB) with the Zurich imaging polarimeter (ZIMPOL), a subsystem of the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the Very Large Telescope (VLT). Our Polarimetric Differential Imaging (PDI) observations probe the disc as close as 0.03 arcsec (3.5 au) to the star and are able to trace the disc out to ˜1.08 arcsec (˜126 au). We find an inner hole, a bright ring bearing substructures around 0.18 arcsec (21 au), and an elliptically shaped gap stretching from 0.25 to 0.47 arcsec (29-55 au). Outside of 0.47 arcsec, the surface brightness drops off, discontinued only by a narrow annular brightness minimum at ˜0.63 to 0.74 arcsec (74-87 au). These observations confirm features found in less-well-resolved data as well as reveal yet undetected indications for planet-disc interactions, such as small-scale structures, star-disc offsets, and potentially moving shadows.

Behavior of Abundances in Chemically Peculiar Dwarf and Subgiant A-Type Stars: HD 23193 and HD 170920

Science.gov (United States)

Kılıçoğlu, Tolgahan; Çalışkan, Şeyma; Ünal, Kübraözge

2018-01-01

To understand the origin of the abundance peculiarities of non-magnetic A-type stars, we present the first detailed chemical abundance analysis of a metallic line star HD 23193 (A2m) and an A-type subgiant HD 170920 (A5), which could have been a HgMn star on the main sequence. Our analysis is based on medium (R ∼ 14,000) and high (R ∼ 40,000) resolution spectroscopic data of the stars. The abundances of 18 elements are derived: C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, and Ba. The masses of HD 23193 and HD 170920 are estimated from evolutionary tracks as 2.3 ± 0.1 M ⊙ and 2.9 ± 0.1 M ⊙. The ages are found to be 635 ± 33 Myr for HD 23193 and 480 ± 50 Myr for HD 170920 using isochrones. The abundance pattern of HD 23193 shows deviations from solar values in the iron-peak elements and indicates remarkable overabundances of Sr (1.16), Y (1.03), and Ba (1.24) with respect to the solar abundances. We compare the derived abundances of this moderately rotating (v\\sin i =37.5 km s‑1) Am star to the theoretical chemical evolution models including rotational mixing. The theoretically predicted abundances resemble our derived abundance pattern, except for a few elements (Si and Cr). For HD 170920, we find nearly solar abundances, except for C (‑0.43), S (0.16), Ti (0.15), Ni (0.16), Zn (0.41), Y (0.57), and Ba (0.97). Its low rotational velocity (v\\sin i=14.5 km s‑1), reduced carbon abundance, and enhanced heavy element abundances suggest that the star is most likely an evolved HgMn star. Based on observations made at the TÜBITAK National Observatory (Program ID 14BRTT150–671), and the Ankara University Observatory, Turkey.

OBJECTS IN KEPLER'S MIRROR MAY BE LARGER THAN THEY APPEAR: BIAS AND SELECTION EFFECTS IN TRANSITING PLANET SURVEYS

International Nuclear Information System (INIS)

Gaidos, Eric; Mann, Andrew W.

2013-01-01

Statistical analyses of large surveys for transiting planets such as the Kepler mission must account for systematic errors and biases. Transit detection depends not only on the planet's radius and orbital period, but also on host star properties. Thus, a sample of stars with transiting planets may not accurately represent the target population. Moreover, targets are selected using criteria such as a limiting apparent magnitude. These selection effects, combined with uncertainties in stellar radius, lead to biases in the properties of transiting planets and their host stars. We quantify possible biases in the Kepler survey. First, Eddington bias produced by a steep planet radius distribution and uncertainties in stellar radius results in a 15%-20% overestimate of planet occurrence. Second, the magnitude limit of the Kepler target catalog induces Malmquist bias toward large, more luminous stars and underestimation of the radii of about one-third of candidate planets, especially those larger than Neptune. Third, because metal-poor stars are smaller, stars with detected planets will be very slightly (<0.02 dex) more metal-poor than the target average. Fourth, uncertainties in stellar radii produce correlated errors in planet radius and stellar irradiation. A previous finding, that highly irradiated giants are more likely to have 'inflated' radii, remains significant, even accounting for this effect. In contrast, transit depth is negatively correlated with stellar metallicity even in the absence of any intrinsic correlation, and a previous claim of a negative correlation between giant planet transit depth and stellar metallicity is probably an artifact.

HD 30187 B and HD 39927 B: Two suspected nearby hot subdwarfs in resolved binaries (based on observations made with the ESA Hipparcos satellite)

DEFF Research Database (Denmark)

Makarov, V.V.; Fabricius, C.

1999-01-01

Stars: Individual: HD 30187 B -- Stars: Individual: HD 39927 B - Stars: White dwarfs - Stars: Binaries: Visual......Stars: Individual: HD 30187 B -- Stars: Individual: HD 39927 B - Stars: White dwarfs - Stars: Binaries: Visual...

THE LICK-CARNEGIE SURVEY: FOUR NEW EXOPLANET CANDIDATES

International Nuclear Information System (INIS)

Meschiari, Stefano; Laughlin, Gregory; Vogt, Steven S.; Rivera, Eugenio J.; Butler, R. Paul; Haghighipour, Nader; Jalowiczor, Peter

2011-01-01

We present new precise HIRES radial velocity (RV) data sets of five nearby stars obtained at Keck Observatory. HD 31253, HD 218566, HD 177830, HD 99492, and HD 74156 are host stars of spectral classes F through K and show RV variations consistent with new or additional planetary companions in Keplerian motion. The orbital parameters of the candidate planets in the five planetary systems span minimum masses of M sin i = 27.43 M + to 8.28 M J , periods of 17.05-4696.95 days and eccentricities ranging from circular to extremely eccentric (e ∼ 0.63). The fifth star, HD 74156, was known to have both a 52 day and a 2500 day planet, and was claimed to also harbor a third planet at 336 days, in apparent support of the 'Packed Planetary System' hypothesis. Our greatly expanded data set for HD 74156 provides strong confirmation of both the 52 day and 2500 day planets, but strongly contradicts the existence of a 336 day planet, and offers no significant evidence for any other planets in the system.

High-contrast imaging of the close environment of HD 142527. VLT/NaCo adaptive optics thermal and angular differential imaging

Science.gov (United States)

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Thébault, P.; Milli, J.; Girard, J. H.; Bonnefoy, M.

2012-10-01

Context. It has long been suggested that circumstellar disks surrounding young stars may be the signposts of planets, and even more so since the recent discoveries of embedded substellar companions. According to models, the planet-disk interaction may create large structures, gaps, rings, or spirals in the disk. In that sense, the Herbig star HD 142527 is particularly compelling, as its massive disk displays intriguing asymmetries that suggest the existence of a dynamical peturber of unknown nature. Aims: Our goal was to obtain deep thermal images of the close circumstellar environment of HD 142527 to re-image the reported close-in structures (cavity, spiral arms) of the disk and to search for stellar and substellar companions that could be connected to their presence. Methods: We obtained high-contrast images with the NaCo adaptive optics system at the Very Large Telescope in L'-band. We applied different analysis strategies using both classical PSF-subtraction and angular differential imaging to probe for any extended structures or point-like sources. Results: The circumstellar environment of HD 142527 is revealed at an unprecedented spatial resolution down to the subarcsecond level for the first time at 3.8 μm. Our images reveal important radial and azimuthal asymmetries that invalidate an elliptical shape for the disk. It instead suggests a bright inhomogeneous spiral arm plus various fainter spiral arms. We also confirm an inner cavity down to 30 AU and two important dips at position angles of 0 and 135 deg. The detection performance in angular differential imaging enables exploration of the planetary mass regime for projected physical separations as close as 40 AU. Use of our detection map together with Monte Carlo simulations sets stringent constraints on the presence of planetary mass, brown dwarf or stellar companions as a function of the semi-major axis. They severely limit any presence of massive giant planets with semi-major axis beyond 50 AU, i

Weekly infusional high-dose fluorouracil (HD-FU), HD-FU plus folinic acid (HD-FU/FA), or HD-FU/FA plus biweekly cisplatin in advanced gastric cancer: randomized phase II trial 40953 of the European Organisation for Research and Treatment of Cancer Gastrointestinal Group and the Arbeitsgemeinschaft Internistische Onkologie.

Science.gov (United States)

Lutz, Manfred P; Wilke, Hansjochen; Wagener, D J Theo; Vanhoefer, Udo; Jeziorski, Krzysztof; Hegewisch-Becker, Susanna; Balleisen, Leopold; Joossens, Eric; Jansen, Rob L; Debois, Muriel; Bethe, Ullrich; Praet, Michel; Wils, Jacques; Van Cutsem, Eric

2007-06-20

This multicentric, randomized, two-stage phase II trial evaluated three simplified weekly infusional regimens of fluorouracil (FU) or FU plus folinic acid (FA) and cisplatin (Cis) with the aim to select a regimen for future phase III trials. A total of 145 patients with advanced gastric cancer where randomly assigned to weekly FU 3,000 mg/m2/24 hours (HD-FU), FU 2,600 mg/m2/24 hours plus dl-FA 500 mg/m2 or l-FA 250 mg/m2 (HD-FU/FA), or FU 2000 mg/m2/24 hours plus FA plus biweekly Cis 50 mg/m2, each administered for 6 weeks with a 1-week rest. The primary end point was the response rate. Confirmed responses were observed in 6.1% (two of 33) of the eligible patients treated with HD-FU, in 25% (12 of 48, including one complete remission [CR]) with HD-FU/FA, and in 45.7% (21 of 46, including four CRs) with HD-FU/FA/Cis. The HD-FU arm was closed after stage 1 because the required minimum number of responses was not met. The median progression-free survival of all patients in the HD-FU, HD-FU/FA, and HD-FU/FA/Cis arm was 1.9, 4.0, and 6.1 months, respectively. The median overall survival was 7.1, 8.9, and 9.7 months, and the survival rate at 1 year was 24.3%, 30.3%, and 45.3%, respectively. Grade 4 toxicities were rare. The most relevant grade 3/4 toxicities were neutropenia in 1.9%, 5.4%, and 19.6%, and diarrhea in 2.7%, 1.9%, and 3.9% of the cycles in the HD-FU, HD-FU/FA, and HD-/FU/Cis arms, respectively. Weekly infusional FU/FA plus biweekly Cis is effective and safe in patients with gastric cancer.

THERMAL TIDES IN FLUID EXTRASOLAR PLANETS

International Nuclear Information System (INIS)

Arras, Phil; Socrates, Aristotle

2010-01-01

Asynchronous rotation and orbital eccentricity lead to time-dependent irradiation of the close-in gas giant exoplanets-the hot Jupiters. This time-dependent surface heating gives rise to fluid motions which propagate throughout the planet. We investigate the ability of this 'thermal tide' to produce a quadrupole moment which can couple to the stellar gravitational tidal force. While previous investigations discussed planets with solid surfaces, here we focus on entirely fluid planets in order to understand gas giants with small cores. The Coriolis force, thermal diffusion, and self-gravity of the perturbations are ignored for simplicity. First, we examine the response to thermal forcing through analytic solutions of the fluid equations which treat the forcing frequency as a small parameter. In the 'equilibrium tide' limit of zero frequency, fluid motion is present but does not induce a quadrupole moment. In the next approximation, finite frequency corrections to the equilibrium tide do lead to a nonzero quadrupole moment, the sign of which torques the planet away from synchronous spin. We then numerically solve the boundary value problem for the thermally forced, linear response of a planet with neutrally stratified interior and a stably stratified envelope. The numerical results find quadrupole moments in agreement with the analytic non-resonant result at a sufficiently long forcing period. Surprisingly, in the range of forcing periods of 1-30 days, the induced quadrupole moments can be far larger than the analytic result due to response of internal gravity waves which propagate in the radiative envelope. We discuss the relevance of our results for the spin, eccentricity, and thermal evolution of hot Jupiters.

Detection of Intermediate-Period Transiting Planets with a Network of Small Telescopes: transitsearch.org

Science.gov (United States)

Seagroves, Scott; Harker, Justin; Laughlin, Gregory; Lacy, Justin; Castellano, Tim

2003-12-01

We describe a project (transitsearch.org) currently attempting to discover transiting intermediate-period planets orbiting bright parent stars, and we simulate that project's performance. The discovery of such a transit would be an important astronomical advance, bridging the critical gap in understanding between HD 209458b and Jupiter. However, the task is made difficult by intrinsically low transit probabilities and small transit duty cycles. This project's efficient and economical strategy is to photometrically monitor stars that are known (from radial velocity surveys) to bear planets, using a network of widely spaced observers with small telescopes. These observers, each individually capable of precision (1%) differential photometry, monitor candidates during the time windows in which the radial velocity solution predicts a transit if the orbital inclination is close to 90°. We use Monte Carlo techniques to simulate the performance of this network, performing simulations with different configurations of observers in order to optimize coordination of an actual campaign. Our results indicate that transitsearch.org can reliably rule out or detect planetary transits within the current catalog of known planet-bearing stars. A distributed network of skilled amateur astronomers and small college observatories is a cost-effective method for discovering the small number of transiting planets with periods in the range 10 days

The radius anomaly in the planet/brown dwarf overlapping mass regime

Directory of Open Access Journals (Sweden)

Baraffe I.

2011-02-01

Full Text Available The recent detection of the transit of very massive substellar companions (Deleuil et al. 2008; Bouchy et al. 2010; Anderson et al. 2010; Bakos et al. 2010 provides a strong constraint to planet and brown dwarf formation and migration mechanisms. Whether these objects are brown dwarfs originating from the gravitational collapse of a dense molecular cloud that, at the same time, gave birth to the more massive stellar companion, or whether they are planets that formed through core accretion of solids in the protoplanetary disk can not always be determined unambiguously and the mechanisms responsible for their short orbital distances are not yet fully understood. In this contribution, we examine the possibility to constrain the nature of a massive substellar object from the various observables provided by the combination of Radial Velocity and Photometry measurements (e.g. Mp , Rp , M⋆, Age, a, e.... In a second part, developments in the modeling of tidal evolution at high eccentricity and inclination - as measured for HD 80 606 with e = 0.9337 (Naef et al. 2001 , XO-3 with a stellar obliquity ε⋆  > 37.3 ± 3.7 deg (Hébrard et al. 2008; Winn et al. 2009 and several other exoplanets - are discussed along with their implication in the understanding of the radius anomaly problem of extrasolar giant planets.

The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer

Energy Technology Data Exchange (ETDEWEB)

Agol, E.; /Washington U., Seattle, Astron. Dept. /Santa Barbara, KITP /UC, Santa Barbara; Cowan, Nicolas B.; /Washington U., Seattle, Astron. Dept.; Knutson, Heather A.; /UC, Berkeley, Astron. Dept.; Deming, Drake; /NASA, Goddard; Steffen, Jason H.; /Fermilab; Henry, Gregory W.; /Tennessee State U.; Charbonneau, David; /Harvard-Smithsonian Ctr. Astrophys.

2010-07-01

We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope IRAC camera at 8 microns, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector 'ramp' variation with a double-exponential function which performs better and is a better physical model for this detector variation. Our main scientific findings are: (1) an upper limit on the variability of the day-side planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 seconds; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the night-side variability of 17% (68% confidence); (5) a better correction for stellar variability at 8 micron causing the phase function to peak 3.5 hours before secondary eclipse, confirming that the advection and radiation timescales are comparable at the 8 micron photosphere; (6) variation in the depth of transit, which possibly implies variations in the surface brightness of the portion of the star occulted by the planet, posing a fundamental limit on non-simultaneous multi-wavelength transit absorption measurements of planet atmospheres; (7) a measurement of the infrared limb-darkening of the star, which is in good agreement with stellar atmosphere models; (8) an offset in the times of secondary eclipse of 69 seconds, which is mostly accounted for by a 31 second light travel time delay and 33 second delay due to the shift of ingress and egress by the planet hot spot; this confirms that the phase variation is due to an offset hot

On Shocks Driven by High-mass Planets in Radiatively Inefficient Disks. III. Observational Signatures in Thermal Emission and Scattered Light

Science.gov (United States)

Hord, Blake; Lyra, Wladimir; Flock, Mario; Turner, Neal J.; Mac Low, Mordecai-Mark

2017-11-01

Recent observations of the protoplanetary disk around the Herbig Be star HD 100546 show two bright features in infrared (H and {L}{\\prime } bands) at about 50 au,with one so far unexplained. We explore the observational signatures of a high-mass planet causing shock heating in order to determine if it could be the source of the unexplained infrared feature in HD 100546. More fundamentally, we identify and characterize planetary shocks as an extra, hitherto ignored, source of luminosity in transition disks. The RADMC-3D code is used to perform dust radiative transfer calculations on the hydrodynamical disk models, including volumetric heating. A stronger shock heating rate by a factor of 20 would be necessary to qualitatively reproduce the morphology of the second infrared source. Instead, we find that the outer edge of the gap carved by the planet heats up by about 50% relative to the initial reference temperature, which leads to an increase in the scale height. The bulge is illuminated by the central star, producing a lopsided feature in scattered light, as the outer gap edge shows an asymmetry in density and temperature attributable to a secondary spiral arm launched not from the Lindblad resonances but from the 2:1 resonance. We conclude that high-mass planets lead to shocks in disks that may be directly observed, particularly at wavelengths of 10 μm or longer, but that they are more likely to reveal their presence in scattered light by puffing up their outer gap edges and exciting multiple spiral arms.

Structure and function of homodomain-leucine zipper (HD-Zip) proteins.

Science.gov (United States)

Elhiti, Mohamed; Stasolla, Claudio

2009-02-01

Homeodomain-leucine zipper (HD-Zip) proteins are transcription factors unique to plants and are encoded by more than 25 genes in Arabidopsis thaliana. Based on sequence analyses these proteins have been classified into four distinct groups: HD-Zip I-IV. HD-Zip proteins are characterized by the presence of two functional domains; a homeodomain (HD) responsible for DNA binding and a leucine zipper domain (Zip) located immediately C-terminal to the homeodomain and involved in protein-protein interaction. Despite sequence similarities HD-ZIP proteins participate in a variety of processes during plant growth and development. HD-Zip I proteins are generally involved in responses related to abiotic stress, abscisic acid (ABA), blue light, de-etiolation and embryogenesis. HD-Zip II proteins participate in light response, shade avoidance and auxin signalling. Members of the third group (HD-Zip III) control embryogenesis, leaf polarity, lateral organ initiation and meristem function. HD-Zip IV proteins play significant roles during anthocyanin accumulation, differentiation of epidermal cells, trichome formation and root development.

Preoperative and intraoperative irradiation for osteosarcoma

International Nuclear Information System (INIS)

Furuya, Kotaro; Amino, Katsuhisa; Kawaguchi, Noriyoshi.

1980-01-01

1) 8 cases of osteosarcoma were treated with preoperative massive irradiation, the over 5 years survival rate was 3/8 (37.5%). 7 out of 8 cases (87.5%) metastasized to the lung. From these result, it is considered that tumorspecific immunological effect can not be expected from irradiation. Irradiation therapy is essentially a local treatment, and therefore systemic chemotherapy is necessary to prevent metastasis. 2) Osteosarcoma was considered to be radioresistant tumor previously, however local control can be obtained by direct view irradiation without the damage of surrounding tissue. This irradiation method is indicated only for young adult in whom the primary tumor is localized. 3) In the experimental study on heterotransplanted human osteosarcoma in nude mice, combined treatment with radiation and chemotherapy (HD-MTX, ADM and EDX) was proven to be more effective as compared with radiation alone. (author)

New ALMA Images of the HD 32297 and HD 61005 Debris Disks

Science.gov (United States)

MacGregor, Meredith Ann; Weinberger, Alycia; Wilner, David; Hughes, A. Meredith; debes, John Henry; Redfield, Seth; Donaldson, Jessica; Nesvold, Erika; Schneider, Glenn; Currie, Thayne; Roberge, Aki; Rodriguez, David

2018-01-01

HD 61005 (G-type star, “The Moth") and HD 32297 (A-type star) host two of the most iconic debris disks. Scattered light images show that both disks are nearly edge-on with dramatic swept-back wings of dust. Previous studies have proposed a range of mechanisms to explain this distinctive morphology including interactions with the interstellar medium, secular perturbations of grains by low-density, neutral interstellar gas, and gravitational interactions with an inclined, eccentric companion. We present new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3 mm that provide the highest resolution images at millimeter wavelengths to date of both systems. Observations at millimeter wavelengths are especially critical to our understanding of the physical mechanisms shaping the structure of these disks, since the large grains that dominate emission at these wavelengths are less affected by stellar radiation and winds and more reliably trace the underlying planetesimal distribution. We fit models directly to the observed visibilities within a Markov Chain Monte Carlo (MCMC) framework to characterize the continuum emission and place constraints on the structure of these unique debris disks. Our new ALMA images reveal that despite differences in spectral type, both systems are best described by a two-component structure with (1) a parent body belt, and (2) an outer halo aligned with the scattered light disk. Such halos have typically been assumed to be composed of small grains visible in scattered light, so these images are some of the first observational evidence that larger grains may also populate extended halos. In addition, we detect significant 12CO gas emission from HD 32297, and determine a robust upper limit for HD 61005.

Exploring H2O Prominence in Reflection Spectra of Cool Giant Planets

Science.gov (United States)

MacDonald, Ryan J.; Marley, Mark S.; Fortney, Jonathan J.; Lewis, Nikole K.

2018-05-01

The H2O abundance of a planetary atmosphere is a powerful indicator of formation conditions. Inferring H2O in the solar system giant planets is challenging, due to condensation depleting the upper atmosphere of water vapor. Substantially warmer hot Jupiter exoplanets readily allow detections of H2O via transmission spectroscopy, but such signatures are often diminished by the presence of clouds composed of other species. In contrast, highly scattering water clouds can brighten planets in reflected light, enhancing molecular signatures. Here, we present an extensive parameter space survey of the prominence of H2O absorption features in reflection spectra of cool (T eff clouds brighten the planet: T eff ∼ 150 K, g ≳ 20 ms‑2, f sed ≳ 3, m ≲ 10× solar. In contrast, planets with g ≲ 20 ms‑2 and T eff ≳ 180 K display substantially prominent H2O features embedded in the Rayleigh scattering slope from 0.4 to 0.73 μm over a wide parameter space. High f sed enhances H2O features around 0.94 μm, and enables these features to be detected at lower temperatures. High m results in dampened H2O absorption features, due to water vapor condensing to form bright, optically thick clouds that dominate the continuum. We verify these trends via self-consistent modeling of the low-gravity exoplanet HD 192310c, revealing that its reflection spectrum is expected to be dominated by H2O absorption from 0.4 to 0.73 μm for m ≲ 10× solar. Our results demonstrate that H2O is manifestly detectable in reflected light spectra of cool giant planets only marginally warmer than Jupiter, providing an avenue to directly constrain the C/O and O/H ratios of a hitherto unexplored population of exoplanetary atmospheres.

Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO

Energy Technology Data Exchange (ETDEWEB)

Follette, Katherine B.; Macintosh, Bruce; Mullen, Wyatt; Bailey, Vanessa P. [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA, 94305 (United States); Rameau, Julien [Institut de Recherche sur les Exoplanètes, Départment de Physique, Université de Montréal, Montréal QC H3C 3J7 (Canada); Dong, Ruobing; Close, Laird M.; Males, Jared R.; Morzinski, Katie M. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Pueyo, Laurent; Perrin, Marshall [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Duchêne, Gaspard; Fung, Jeffrey; Wang, Jason [Astronomy Department, University of California, Berkeley, Berkeley CA 94720 (United States); Leonard, Clare; Spiro, Elijah [Physics and Astronomy Department, Amherst College, 21 Merrill Science Drive, Amherst, MA 01002 (United States); Marois, Christian [National Research Council of Canada Herzberg, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Millar-Blanchaer, Maxwell A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Ammons, S. Mark [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Barman, Travis [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); and others

2017-06-01

We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total intensity imagery, and MagAO data are taken in Simultaneous Differential Imaging mode at H α . The new GPI H -band total intensity data represent a significant enhancement in sensitivity and field rotation compared to previous data sets and enable a detailed exploration of substructure in the disk. The data are processed with a variety of differential imaging techniques (polarized, angular, reference, and simultaneous differential imaging) in an attempt to identify the disk structures that are most consistent across wavelengths, processing techniques, and algorithmic parameters. The inner disk cavity at 15 au is clearly resolved in multiple data sets, as are a variety of spiral features. While the cavity and spiral structures are identified at levels significantly distinct from the neighboring regions of the disk under several algorithms and with a range of algorithmic parameters, emission at the location of HD 100546 “ c ” varies from point-like under aggressive algorithmic parameters to a smooth continuous structure with conservative parameters, and is consistent with disk emission. Features identified in the HD 100546 disk bear qualitative similarity to computational models of a moderately inclined two-armed spiral disk, where projection effects and wrapping of the spiral arms around the star result in a number of truncated spiral features in forward-modeled images.

Splenic irradiation before bone marrow transplantation for chronic myeloid leukaemia

International Nuclear Information System (INIS)

Gratwohl, A.; Hermans, J.; Biezen, A.V.

1996-01-01

A total of 229 patients with chronic myeloid leukaemia (CML) in chronic phase were randomized between 1986 and 1990 to receive or not receive additional splenic irradiation as part of their conditioning prior to bone marrow transplantation (BMT). Both groups, 115 patients with and 114 patients without splenic irradiation, were very similar regarding distribution of age, sex, donor/recipient sex combination, conditioning, graft-versus-host disease (GvHD) prevention method and blood counts at diagnosis or prior to transplant. 135 patients (59%) are alive as of October 1995 with a minimum follow-up of 5 years. 52 patients have relapsed (23%), 26 patients in the irradiated, 26 patients in the non-irradiated group (n.s.) with a relapse incident at 6 years of 28%. The main risk factor for relapse was T-cell depletion as the method for GvHD prevention, and an elevated basophil count in the peripheral blood prior to transplant. Relapse incidence between patients with or without splenic irradiation was no different in patients at high risk for relapse, e.g. patients transplanted with T-cell-depleted marrows (P = n.s.) and in patients with low risk for relapse, e.g. patients transplanted with non-T-cell-depleted transplants and basophil counts 3% basophils in peripheral blood). In this patient group, relapse incidence was 11% at 6 years with splenic irradiation but 32% in the non-irradiated group (P = 0.05). Transplant-related mortality was similar whether patients received splenic irradiation or not. This study suggests an advantage in splenic irradiation prior to transplantation for CML in this subgroup of patients and illustrates the need for tailored therapy. (Author)

HD 101065, the Most Peculiar Star

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... In this paper we discuss the prospects for asteroseismology with spatial resolution and motivate studies of the most chemically peculiar roAp star HD 101065. We present the first results from a high-precision radial velocity (RV) study of HD 101065 based on data spanning four nights that were acquired ...

ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS

International Nuclear Information System (INIS)

Lissauer, Jack J.; Rowe, Jason F.; Bryson, Stephen T.; Howell, Steve B.; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G.; Marcy, Geoffrey W.; Adams, Elisabeth; Fressin, Francois; Geary, John; Holman, Matthew J.; Ragozzine, Darin; Buchhave, Lars A.; Ciardi, David R.; Cochran, William D.; Fabrycky, Daniel C.; Ford, Eric B.; Morehead, Robert C.; Gilliland, Ronald L.

2012-01-01

We present a statistical analysis that demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) indeed represent true, physically associated transiting planets. Binary stars provide the primary source of false positives among Kepler planet candidates, implying that false positives should be nearly randomly distributed among Kepler targets. In contrast, true transiting planets would appear clustered around a smaller number of Kepler targets if detectable planets tend to come in systems and/or if the orbital planes of planets encircling the same star are correlated. There are more than one hundred times as many Kepler planet candidates in multi-candidate systems as would be predicted from a random distribution of candidates, implying that the vast majority are true planets. Most of these multis are multiple-planet systems orbiting the Kepler target star, but there are likely cases where (1) the planetary system orbits a fainter star, and the planets are thus significantly larger than has been estimated, or (2) the planets orbit different stars within a binary/multiple star system. We use the low overall false-positive rate among Kepler multis, together with analysis of Kepler spacecraft and ground-based data, to validate the closely packed Kepler-33 planetary system, which orbits a star that has evolved somewhat off of the main sequence. Kepler-33 hosts five transiting planets, with periods ranging from 5.67 to 41 days.

ALMA OBSERVATIONS OF HD 141569’s CIRCUMSTELLAR DISK

Energy Technology Data Exchange (ETDEWEB)

White, J. A.; Boley, A. C. [Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Hughes, A. M.; Flaherty, K. M. [Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Ford, E. [Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802-2111 (United States); Wilner, D.; Payne, M. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Corder, S., E-mail: jawhite@astro.ubc.ca [North American ALMA Science Center, National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903 (United States)

2016-09-20

We present ALMA band 7 (345 GHz) continuum and {sup 12}CO( J = 3-2) observations of the circumstellar disk surrounding HD 141569. At an age of about 5 Myr, the disk has a complex morphology that may be best interpreted as a nascent debris system with gas. Our 870 μ m ALMA continuum observations resolve a dust disk out to approximately 56 au from the star (assuming a distance of 116 pc) with 0.″38 resolution and 0.07 mJy beam{sup −1} sensitivity. We measure a continuum flux density for this inner material of 3.8 ± 0.4 mJy (including calibration uncertainties). The {sup 12}CO(3-2) gas is resolved kinematically and spatially from about 30 to 210 au. The integrated {sup 12}CO(3-2) line flux density is 15.7 ± 1.6 Jy km s{sup −1}. We estimate the mass of the millimeter debris and {sup 12}CO(3-2) gas to be ≳0.04 M {sub ⊕} and ∼2 × 10{sup −3} M {sub ⊕}, respectively. If the millimeter grains are part of a collisional cascade, then we infer that the inner disk (<50 au) has ∼160 M {sub ⊕} contained within objects less than 50 km in radius, depending on the planetesimal size distribution and density assumptions. Markov Chain Monte Carlo modeling of the system reveals a disk morphology with an inclination of 53.°4 centered around an M = 2.39 M {sub ⊙} host star ( M sin( i ) = 1.92 M {sub ⊙}). We discuss whether the gas in HD 141569's disk may be second generation. If it is, the system can be used to study the clearing stages of planet formation.

Quality control of involved field radiotherapy in the HD 13 and HD 14 trials. Report of the radiotherapy panel of the German Hodgkin Study Group (GHSG)

Energy Technology Data Exchange (ETDEWEB)

Kriz, J.; Haverkamp, U.; Eich, H.T. [University of Muenster, Department of Radiation Oncology, Muenster (Germany); Baues, C. [University of Cologne, Department of Radiation Oncology, Cologne (Germany); Engenhart-Cabillic, R. [University of Marburg, Department of Radiation Oncology, Marburg (Germany); Herfarth, K. [University of Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); Lukas, P. [University of Innsbruck, Department of Radiation Oncology, Innsbruck (Austria); Pluetschow, A.; Fuchs, M.; Engert, A. [University of Cologne, Department of Internal Medicine, Cologne (Germany); Schmidberger, H. [University of Mainz, Department of Radiation Oncology, Mainz (Germany); Staar, S. [Bremen Mitte, Department of Radiation Oncology, Bremen (Germany)

2017-02-15

As part of the foundation of the German Hodgkin Study Group (GHSG) in 1978, a central radiotherapy (RT) reference centre was established to evaluate and to improve the quality of treatment. During the study generations, the quality assurance programs (QAP) were continued and adapted to the demands of each study. The purpose of this article is to demonstrate the results of the fifth study generation and to compare them to the previous findings. With the start of the fourth GHSG study generation (HD10-12), a central prospective review of all diagnostic images was established to create an individual treatment plan for each early stage study patient. The quality of involved field RT was retrospectively evaluated by an expert panel of radiation oncologists. In the fifth study generation (HD13-15), the retrospective review of radiotherapy performed was refined and the results were compared with the findings of the fourth generation. The expert panel analyzed the RT planning and application of 1037 (28 %) patients (HD13 n = 465, HD14 n = 572). Simulation films were available in 85 % of cases and verification films in 87 %. RT was assessed as major violation in 46 % (HD13 = 38 %, HD14 = 52 %), minor violation in 9 % (HD13 = 9 %, HD14 = 9 %) and according to the protocol in 45 % (HD13 = 52 %, HD14 = 38 %). The value for QAP of RT within the GHSG trials is well known. Still there were several protocol violations. In the future, the QAP program has to be adapted to the requirements of ''modern RT'' in malignant lymphoma. (orig.) [German] Seit Gruendung der German Hodgkin Study Group (GHSG) im Jahr 1978 wurde ein zentrales Qualitaetssicherungsprogramm (QAP) der Radiotherapie (RT) etabliert, um die Qualitaet der RT sicherzustellen. Waehrend der fortlaufenden Studiengenerationen wurde dieses QAP kontinuierlich weiterentwickelt. In dieser Auswertung werden die Ergebnisse der fuenften Studiengeneration (HD13-15) praesentiert und mit frueheren Ergebnissen

Constraints on planet formation from Kepler’s multiple planet systems

Science.gov (United States)

Quintana, Elisa V.

2015-01-01

The recent haul of hundreds of multiple planet systems discovered by Kepler provides a treasure trove of new clues for planet formation theories. The substantial amount of protoplanetary disk mass needed to form the most commonly observed multi-planet systems - small (Earth-sized to mini-Neptune-sized) planets close to their stars - argues against pure in situ formation and suggests that the planets in these systems must have undergone some form of migration. I will present results from numerical simulations of terrestrial planet formation that aim to reproduce the sizes and architecture of Kepler's multi-planet systems, and will discuss the observed resonances and giant planets (or the lack thereof) associated with these systems.

GPI Spectroscopy of the Mass, Age, and Metallicity Benchmark Brown Dwarf HD 4747 B

Science.gov (United States)

Crepp, Justin R.; Principe, David A.; Wolff, Schuyler; Giorla Godfrey, Paige A.; Rice, Emily L.; Cieza, Lucas; Pueyo, Laurent; Bechter, Eric B.; Gonzales, Erica J.

2018-02-01

The physical properties of brown dwarf companions found to orbit nearby, solar-type stars can be benchmarked against independent measures of their mass, age, chemical composition, and other parameters, offering insights into the evolution of substellar objects. The TRENDS high-contrast imaging survey has recently discovered a (mass/age/metallicity) benchmark brown dwarf orbiting the nearby (d = 18.69 ± 0.19 pc), G8V/K0V star HD 4747. We have acquired follow-up spectroscopic measurements of HD 4747 B using the Gemini Planet Imager to study its spectral type, effective temperature, surface gravity, and cloud properties. Observations obtained in the H-band and K 1-band recover the companion and reveal that it is near the L/T transition (T1 ± 2). Fitting atmospheric models to the companion spectrum, we find strong evidence for the presence of clouds. However, spectral models cannot satisfactorily fit the complete data set: while the shape of the spectrum can be well-matched in individual filters, a joint fit across the full passband results in discrepancies that are a consequence of the inherent color of the brown dwarf. We also find a 2σ tension in the companion mass, age, and surface gravity when comparing to evolutionary models. These results highlight the importance of using benchmark objects to study “secondary effects” such as metallicity, non-equilibrium chemistry, cloud parameters, electron conduction, non-adiabatic cooling, and other subtleties affecting emergent spectra. As a new L/T transition benchmark, HD 4747 B warrants further investigation into the modeling of cloud physics using higher resolution spectroscopy across a broader range of wavelengths, polarimetric observations, and continued Doppler radial velocity and astrometric monitoring.

Design of a polarized target made of pure HD: analysis and distillation of HD, resonant virtual Compton scattering on the nucleon at TJNAF; Developpement d'une cible polarisee de pur HD: analyse et distillation du HD, diffusion compton virtuelle resonante sur le nucleon a TJNAF

Energy Technology Data Exchange (ETDEWEB)

Bouchigny, S

2004-04-01

The first part describe my work on the frozen spin target project HYDILE. This target has to be made of very pure HD (Hydrogen Deuterium), better than 99.95%. However, commercial HD is never found with a concentration better than 98%. The goal was, then, to build an HD distillation facility which could produce pure HD. We describe, in this thesis, the design of the distillator and the implementation of a quadrupole mass spectrometer to monitor the HD purity during the distillation process. The second part of the thesis concerns the analysis taken at the electron accelerator facility TJNAF (Virginia, USA). We look at the electroproduction of Delta resonances involving Deep Virtual Compton Scattering (DeltaVCS). The interpretation of this reaction in terms of GPDs (Generalized Parton Distribution) can provide new insights to the nucleon structure. We focus on the measurement of the beam spin asymmetry which comes from the interference of the Bethe Heitler process with the DeltaVCS. (author)

Elemental abundance studies of CP stars. II. The silicon stars HD 133029 and HD 192913

CERN Document Server

López-García, Z

1999-01-01

For pt.1 see ibid., vol.107, no.2, p.353-63 (1994). Fine analyses of the silicon stars HD 133029 and HD 192913 are presented using ATLAS9 model atmospheres whose predictions fit the optical region spectrophotometry and H gamma profiles and have the same bulk metallicity as the deduced abundances. Both are very He poor stars. The light elements are mostly solar except for silicon, and all the heavier elements, except nickel in HD 133029 which is solar, are greatly overabundant. The iron peak elements are typically 10 times overabundant. SrYZr are of order of 100 times solar. The rare earths are 1000 or more times overabundant. Table 4 is is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. (50 refs).

A Planet Soon to Meet Its Demise

Science.gov (United States)

Kohler, Susanna

2017-02-01

A tiny telescope has discovered a scalding hot world orbiting its star 1,300 light-years from us. KELT-16b may only be around for a few more hundreds of thousands of years, however.Dont Underestimate Tiny TelescopesThe KELT-North telescope in Arizona. This tiny telescope was responsible for the discovery of KELT-16b. [Vanderbilt University]In an era of ever larger observatories, you might think that theres no longer a place for small-aperture ground-based telescopes. But small ground-based telescopes have been responsible for the discovery and characterization of around 250 exoplanets so far and these are the targets that are especially useful for exoplanet science, as they aremore easily followed up than the faint discoveries made by telescopes like Kepler.The Kilogree Extremely Little Telescope (KELT) consists of two telescopes one in Arizona and one in South Africa that each have a 4.2-centimeter aperture. In total, KELT observes roughly 70% of the entire sky searching for planets transiting bright hosts. And its recently found quite an interesting one: KELT-16b. In a publication led by Thomas Oberst (Westminster College in Pennsylvania), a team of scientists presents their find.Combined follow-up light curves obtained for KELT-16b from 19 transits. The best-fit period is just under a day. [Oberst et al. 2017]A Hot WorldKELT-16b is whats known as a hot Jupiter. Using the KELT data and follow-up observations of 19 transits, Oberst and collaborators estimate KELT-16bs radius at roughly 1.4 times that of Jupiter and its mass at 2.75 times Jupiters. Its equilibrium temperature is a scalding 2453 K caused by the fact that it orbits so close to its host star that it completes each orbit in a mere 0.97 days!This short period is extremely unusual: there are only five other known transiting exoplanets with periods shorter than a day. KELT-16b is orbiting very close to its host, making it subject to extreme irradiation and strong tidal forces.Based on KELT-16bs orbit

ALMA 1.3 Millimeter Map of the HD 95086 System -- A Young Analog of the HR 8799 System

Science.gov (United States)

Su, Kate; MacGregor, Meredith Ann; Booth, Mark; Wilner, David; Malhotra, Renu; Morrison, Sarah; OST STDT

2018-01-01

Planets and minor bodies such as asteroids, Kuiper-belt objects and comets are integral components of a planetary system. Interactions among them leave clues about the formation process of a planetary system. The signature of such interactions is best illustrated through resolved observations of its debris disk. Here we present ALMA 1.3 mm observations of HD 95086, a young analog of the HR 8799 system, that hosts a directly imaged giant planet b and a massive debris disk with both asteroid- and Kuiper-belt analogs. The location of the Kuiper-belt analog is resolved for the first time. Our deep ALMA map also reveals a bright source located near the edge of the ring. The properties of the source, based on limited data, are consistent with it being a luminous star-forming galaxy at high redshift. We will discuss future, resolved observations of debris disks, highlighting the potential of the Origins Space Telescope (OST), one of the four science and technology definition studies commissioned by NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey.

Banana (Musa. spp.) strain HD-1 appraisal

International Nuclear Information System (INIS)

Longyan, G.; Xinguo, L.; Lingxia, W.; Xuefei, J.

2016-01-01

Being one of the important tropical and subtropical fruit trees, banana (Musa spp.) belongs to the family Musaceae and the order Scitaminae with two genera, Musa and Ensete. In a field survey, research team has discovered a potential banana mutant strain HD-1 with a sound economic value. The results of the finding are as follows: based on Simmonds classification, the pseudostem of banana strain HD-1 is relatively short and purplish red; its upright outward petiole groove has red edges and wraps its pseudostem loosely. Its ploidy is 3, AAA type. Karyotype analysis shows that the number of chromosomes is 33, the karyotype formula is 2n=3x=33=2L + 3 M2 + 4 M1 + 2 S, HD-1 is classified as 1B type. With the help of ISSR molecular markers, we find thatbanana HD-1 has the closest relationship with Pubei and Tianbao dwarf banana; the similarity coefficient is 0.81. In an artificial simulation tests of cold, drought and salt resistance environment changes of physiological and biochemical indexes indicate that HD-1 exhibits stronger defense capability than Brazil banana. By way of inoculation with injury of root dipping method, we respectively treat two kinds of banana seedlings inoculated Banana Fusarium wilt race 4 small species. The results show that their resistance evaluation scores are 3 and 4, disease levels are susceptible and high sensitivity respectively. We conclude that HD-1 has stronger resistance ability to Fusarium wilt than Brazil banana. (author)

Further investigation of the role of HLA-DPB1 in adult Hodgkin's disease (HD) suggests an influence on susceptibility to different HD subtypes.

OpenAIRE

Taylor, G.M.; Gokhale, D.A.; Crowther, D.; Woll, P.J.; Harris, M.; Ryder, D.; Ayres, M.; Radford, J.A.

1999-01-01

It has been suggested in a number of studies that susceptibility to adult Hodgkin's disease (HD) is influenced by the HLA class II region, and specifically by alleles at the HLA-DPB1 locus. Since HD is diagnostically complex, it is not clear whether different HLA-DPB1 alleles confer susceptibility to different HD subtypes. To clarify this we have extended a previous study to type DPB1 alleles in 147 adult HD patients from a single centre. We have analysed patients with nodular sclerosing (NS)...

Listeria monocytogenes infection of HD11, chicken macrophage-like cells.

Science.gov (United States)

Jarvis, N A; Donaldson, J R; O'Bryan, C A; Ricke, S C; Crandall, P G

2017-04-01

Listeria monocytogenes can be carried by and infect poultry, although the clinical disease in birds is rare. Escape from macrophage phagocytosis is a key step in pathogenesis for L. monocytogenes. Therefore, we investigated the infection of the chicken macrophage-like cell line HD11 with 2 strains of L. monocytogenes EGD-e and Scott A. After infection, L. monocytogenes was quantified by spread plating and HD11 was quantified with trypan blue exclusion stain before enumeration. The standard macrophage killing protocols require washing the cell monolayers 3 times with PBS, which was found to negatively influence HD11 monolayers. Maximum bacterial densities within macrophages were not different between the 2 Listeria strains. HD11 required more than 11 h to effectively reduce intracellular L. monocytogenes Scott A, and Scott A was more susceptible to HD11 killing than EGD-e. It appears that Listeria infection initially causes attenuation of HD11 growth, and infected HD11 cells do not begin to lyse until at least 11 h post infection. These results suggest that there are subtle strain to strain differences in response to HD11 macrophage phagocytosis. The long lead-time required for HD11 to kill L. monocytogenes cells means that there is sufficient time available for chicken macrophages to circulate in the blood and transfer the intracellular Listeria to multiple tissues. © 2016 Poultry Science Association Inc.

Game-based combined cognitive and neurofeedback training using Focus Pocus reduces symptom severity in children with diagnosed AD/HD and subclinical AD/HD.

Science.gov (United States)

Johnstone, Stuart J; Roodenrys, Steven J; Johnson, Kirsten; Bonfield, Rebecca; Bennett, Susan J

2017-06-01

Previous studies report reductions in symptom severity after combined working memory (WM) and inhibitory control (IC) training in children with AD/HD. Based on theoretical accounts of the role of arousal/attention modulation problems in AD/HD, the current study examined the efficacy of combined WM, IC, and neurofeedback training in children with AD/HD and subclinical AD/HD. Using a randomized waitlist control design, 85 children were randomly allocated to a training or waitlist condition and completed pre- and post-training assessments of overt behavior, trained and untrained cognitive task performance, and resting and task-related EEG activity. The training group completed twenty-five sessions of training using Focus Pocus software at home over a 7 to 8-week period. Trainees improved at the trained tasks, while enjoyment and engagement declined across sessions. After training, AD/HD symptom severity was reduced in the AD/HD and subclinical groups according to parents, and in the former group only according to blinded teachers and significant-others. There were minor improvements in two of six near-transfer tasks, and evidence of far-transfer of training effects in four of five far-transfer tasks. Frontal region changes indicated normalization of atypical EEG features with reduced delta and increased alpha activity. It is concluded that technology developments provide an interesting a vehicle for delivering interventions and that, while further research is needed, combined WM, IC, and neurofeedback training can reduce AD/HD symptom severity in children with AD/HD and may also be beneficial to children with subclinical AD/HD. Copyright © 2017 Elsevier B.V. All rights reserved.

Probing peptide fragment ion structures by combining sustained off-resonance collision-induced dissociation and gas-phase H/D exchange (SORI-HDX) in Fourier transform ion-cyclotron resonance (FT-ICR) instruments.

Science.gov (United States)

Somogyi, Arpád

2008-12-01

The usefulness of gas-phase H/D exchange is demonstrated to probe heterogeneous fragment and parent ion populations. Singly and multiply protonated peptides/proteins were fragmented by using sustained off-resonance irradiation collision-induced dissociation (SORI-CID). The fragments and the surviving precursor ions then all undergo H/D exchange in the gas-phase with either D(2)O or CD(3)OD under the same experimental conditions. Usually, 10 to 60 s of reaction time is adequate to monitor characteristic differences in the H/D exchange kinetic rates. These differences are then correlated to isomeric ion structures. The SORI-HDX method can be used to rapidly test fragment ion structures and provides useful insights into peptide fragmentation mechanisms.

SUBSTELLAR-MASS COMPANIONS TO THE K-DWARF BD+14 4559 AND THE K-GIANTS HD 240210 AND BD+20 2457

International Nuclear Information System (INIS)

Niedzielski, A.; Nowak, G.; Adamow, M.; Wolszczan, A.

2009-01-01

We present the discovery of substellar-mass companions to three stars by the ongoing Penn State-Torun Planet Search conducted with the 9.2 m Hobby-Eberly Telescope. The K2-dwarf, BD+14 4559, has a 1.5 M J minimum mass companion with the orbital period of 269 days and shows a non-linear, long-term radial velocity (RV) trend, which indicates a possible presence of another planet-mass body in the system. The K3-giant, HD 240210, exhibits RV variations that require modeling with multiple orbits, but the available data are not yet sufficient to do it unambiguously. A tentative, one-planet model calls for a 5.2 M J minimum mass planet in a 502 day orbit around the star. The most massive of the three stars, the K2-giant, BD+20 2457, whose estimated mass is 2.8 ± 1.5 M sun , has two companions with the respective minimum masses of 21.4 M J and 12.5 M J and orbital periods of 380 and 622 days. Depending on the unknown inclinations of the orbits, the currently very uncertain mass of the star, and the dynamical properties of the system, it may represent the first detection of two brown dwarf-mass companions orbiting a giant. The existence of such objects will have consequences for the interpretation of the so-called brown dwarf desert known to exist in the case of solar-mass stars.

Absolute parameters of southern detached eclipsing binary: HD 53570

Science.gov (United States)

Sürgit, D.

2018-05-01

In this study, we conducted the first analysis of spectroscopic and photometric observations of the eclipsing binary star HD 53570. Spectroscopic observations of HD 53570 were made at the Sutherland Station of the South African Astronomical Observatory in 2013 and 2014. The radial velocities of the components were determined using the cross-correlation technique. The spectroscopic mass ratio obtained for the system was 1.13 ( ± 0.07). The All Sky Automated Survey V light curve of HD 53570 was analyzed using the Wilson-Devinney code combined with the Monte Carlo search method. The final model showed that HD 53570 has a detached configuration. The mass and radii of the primary and secondary components of HD 53570 were derived as 1.06 ( ± 0.07) M⊙, 1.20 ( ± 0.16) M⊙, and 1.42 ( ± 0.14) R⊙, 2.07 ( ± 0.16) R⊙, respectively. The distance of HD 53570 was computed as 248 ( ± 38) pc considering interstellar extinction. The evolutionary status of the component stars was also investigated using Geneva evolutionary models.

Results of a Long-Term Spectral and Photometric Monitoring of the Herbig Ae Star HD 179218

Science.gov (United States)

Kozlova, O. V.; Alekseev, I. Yu.

2017-06-01

We present the results of the long-term spectroscopic and photometric monitoring of the Herbig Ae star HD 179218. The high-resolution spectra (R = 20000) were made on the 2.6-m telescope at the Crimean Astrophysical Observatory (CrAO) in the regions of Hα emission line. The photometric observations were obtained on 1.25-m telescope AZT-11 (CrAO) equipped with the UBVRI electrophotometer-polarimeter. Our results showed that Hα emission parameters demonstrate the long- term variability on the time scale about 4000 days. The same variability is observed in the change of the stellar brightness in V-band. The unusual behavior the V-I color index depending on the stellar brightness in the V-band can be concluded that around the star there is an additional source of IR-radiation. We believe that the obtained results can be explained by the presence in the vicinity of HD 179218 a low-mass component.

Young planets under extreme UV irradiation. I. Upper atmosphere modelling of the young exoplanet K2-33b

Science.gov (United States)

Kubyshkina, D.; Lendl, M.; Fossati, L.; Cubillos, P. E.; Lammer, H.; Erkaev, N. V.; Johnstone, C. P.

2018-04-01

The K2-33 planetary system hosts one transiting 5 R⊕ planet orbiting the young M-type host star. The planet's mass is still unknown, with an estimated upper limit of 5.4 MJ. The extreme youth of the system (age of the system indicates that the planet is more massive than 10 M⊕.

Cancer-Associated Fibroblasts from lung tumors maintain their immuno-suppressive abilities after high-dose irradiation

Directory of Open Access Journals (Sweden)

Laia eGorchs

2015-05-01

Full Text Available Accumulating evidence supports the notion that high-dose (>5 Gy radiotherapy (RT regimens are triggering stronger pro-immunogenic effects than standard low-dose (2 Gy regimens. However, the effects of RT on certain immunoregulatory elements in tumors remain unexplored. In this study we have investigated the effects of high-dose irradiation (HD-RT on the immunomodulating functions of cancer-associated fibroblasts (CAFs. Primary CAF cultures were established from lung cancer specimens derived from patients diagnosed for non-small cell lung cancer. Irradiated and non-irradiated CAFs were examined for immunomodulation in experiments with peripheral blood mononuclear cells from random, healthy donors. Regulation of lymphocytes behavior was checked by lymphocyte proliferation assays, lymphocyte migration assays and T-cell cytokine production. Additionally, CAF-secreted immuno-regulatory factors were studied by multiplex protein arrays, ELISAs and by LC-MS/MS proteomics. In all functional assays we observed a powerful immuno-suppressive effect exerted by CAF-conditioned medium on activated T-cells (p>0,001, and this effect was sustained after a single radiation dose of 18 Gy. Relevant immuno-suppressive molecules such as prostaglandin E2, interleukin-6 and -10, or transforming growth factor-β were found in CAF conditioned medium, but their secretion was unchanged after irradiation. Finally, immunogenic cell death responses in CAFs were studied by exploring the release of high motility group box-1 and ATP. Both alarmins remained undetectable before and after irradiation. In conclusion, CAFs play a powerful immuno-suppressive effect over activated T-cells, and this effect remains unchanged after HD-RT. Importantly, CAFs do not switch on immunogenic cell death responses after exposure to HD-RT.

The origin of methane and biomolecules from a CO2 cycle on terrestrial planets

Science.gov (United States)

Civiš, Svatopluk; Knížek, Antonín; Ivanek, Ondřej; Kubelík, Petr; Zukalová, Markéta; Kavan, Ladislav; Ferus, Martin

2017-10-01

Understanding the chemical evolution of newly formed terrestrial planets involves uncertainties in atmospheric chemical composition and assessing the plausibility of biomolecule synthesis. In this study, an original scenario for the origin of methane on Mars and terrestrial planets is suggested. Carbon dioxide in Martian and other planetary atmospheres can be abiotically converted into a mixture of methane and carbon monoxide by `methanogenesis' on porous mineral photoactive surfaces under soft ultraviolet irradiation. On young planets exposed to heavy bombardment by interplanetary matter, this process can be followed by biomolecule synthesis through the reprocessing of reactive reducing atmospheres by impact-induced shock waves. The proposed mechanism of methanogenesis may help to answer the question concerning the formation of methane and carbon monoxide by photochemical processes, the formation of biomolecules on early Earth and other terrestrial planets, and the source and seasonal variation of methane concentrations on Mars.

EFFECTS OF DYNAMICAL EVOLUTION OF GIANT PLANETS ON SURVIVAL OF TERRESTRIAL PLANETS

International Nuclear Information System (INIS)

Matsumura, Soko; Ida, Shigeru; Nagasawa, Makiko

2013-01-01

The orbital distributions of currently observed extrasolar giant planets allow marginally stable orbits for hypothetical, terrestrial planets. In this paper, we propose that many of these systems may not have additional planets on these ''stable'' orbits, since past dynamical instability among giant planets could have removed them. We numerically investigate the effects of early evolution of multiple giant planets on the orbital stability of the inner, sub-Neptune-like planets which are modeled as test particles, and determine their dynamically unstable region. Previous studies have shown that the majority of such test particles are ejected out of the system as a result of close encounters with giant planets. Here, we show that secular perturbations from giant planets can remove test particles at least down to 10 times smaller than their minimum pericenter distance. Our results indicate that, unless the dynamical instability among giant planets is either absent or quiet like planet-planet collisions, most test particles down to ∼0.1 AU within the orbits of giant planets at a few AU may be gone. In fact, out of ∼30% of survived test particles, about three quarters belong to the planet-planet collision cases. We find a good agreement between our numerical results and the secular theory, and present a semi-analytical formula which estimates the dynamically unstable region of the test particles just from the evolution of giant planets. Finally, our numerical results agree well with the observations, and also predict the existence of hot rocky planets in eccentric giant planet systems.

Quality control of involved field radiotherapy in the HD 13 and HD 14 trials. Report of the radiotherapy panel of the German Hodgkin Study Group (GHSG)

International Nuclear Information System (INIS)

Kriz, J.; Haverkamp, U.; Eich, H.T.; Baues, C.; Engenhart-Cabillic, R.; Herfarth, K.; Lukas, P.; Pluetschow, A.; Fuchs, M.; Engert, A.; Schmidberger, H.; Staar, S.

2017-01-01

As part of the foundation of the German Hodgkin Study Group (GHSG) in 1978, a central radiotherapy (RT) reference centre was established to evaluate and to improve the quality of treatment. During the study generations, the quality assurance programs (QAP) were continued and adapted to the demands of each study. The purpose of this article is to demonstrate the results of the fifth study generation and to compare them to the previous findings. With the start of the fourth GHSG study generation (HD10-12), a central prospective review of all diagnostic images was established to create an individual treatment plan for each early stage study patient. The quality of involved field RT was retrospectively evaluated by an expert panel of radiation oncologists. In the fifth study generation (HD13-15), the retrospective review of radiotherapy performed was refined and the results were compared with the findings of the fourth generation. The expert panel analyzed the RT planning and application of 1037 (28 %) patients (HD13 n = 465, HD14 n = 572). Simulation films were available in 85 % of cases and verification films in 87 %. RT was assessed as major violation in 46 % (HD13 = 38 %, HD14 = 52 %), minor violation in 9 % (HD13 = 9 %, HD14 = 9 %) and according to the protocol in 45 % (HD13 = 52 %, HD14 = 38 %). The value for QAP of RT within the GHSG trials is well known. Still there were several protocol violations. In the future, the QAP program has to be adapted to the requirements of ''modern RT'' in malignant lymphoma. (orig.) [de

Discovery of Temperate Earth-Sized Planets Transiting a Nearby Ultracool Dwarf Star

Science.gov (United States)

Jehin, Emmanuel; Gillon, Michael; Lederer, Susan M.; Delrez, Laetitia; De Wit, Julien; Burdanov, Artem; Van Grootel, Valerie; Burgasser, Adam; Triaud, Amaury; Demory, Brice-Olivier;

ROVIBRATIONAL QUENCHING RATE COEFFICIENTS OF HD IN COLLISIONS WITH He

International Nuclear Information System (INIS)

Nolte, J. L.; Stancil, P. C.; Lee, T.-G.; Balakrishnan, N.; Forrey, R. C.

2012-01-01

Along with H 2 , HD has been found to play an important role in the cooling of the primordial gas for the formation of the first stars and galaxies. It has also been observed in a variety of cool molecular astrophysical environments. The rate of cooling by HD molecules requires knowledge of collisional rate coefficients with the primary impactors, H, He, and H 2 . To improve knowledge of the collisional properties of HD, we present rate coefficients for the He-HD collision system over a range of collision energies from 10 –5 to 5 × 10 3 cm –1 . Fully quantum mechanical scattering calculations were performed for initial HD rovibrational states of j = 0 and 1 for v = 0-17 which utilized accurate diatom rovibrational wave functions. Rate coefficients of all Δv = 0, –1, and –2 transitions are reported. Significant discrepancies with previous calculations, which adopted a small basis and harmonic HD wave functions for excited vibrational levels, were found for the highest previously considered vibrational state of v = 3. Applications of the He-HD rate coefficients in various astrophysical environments are briefly discussed.

PLANET HUNTERS: ASSESSING THE KEPLER INVENTORY OF SHORT-PERIOD PLANETS

International Nuclear Information System (INIS)

Schwamb, Megan E.; Lintott, Chris J.; Lynn, Stuart; Smith, Arfon M.; Simpson, Robert J.; Fischer, Debra A.; Giguere, Matthew J.; Brewer, John M.; Parrish, Michael; Schawinski, Kevin

2012-01-01

We present the results from a search of data from the first 33.5 days of the Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters citizen science project. Planet Hunters enlists members of the general public to visually identify transits in the publicly released Kepler light curves via the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data set. We examine the abundance of ≥2 R ⊕ planets on short-period ( ⊕ Planet Hunters ≥85% efficient at identifying transit signals for planets with periods less than 15 days for the Kepler sample of target stars. Our high efficiency rate for simulated transits along with recovery of the majority of Kepler ≥4 R ⊕ planets suggests that the Kepler inventory of ≥4 R ⊕ short-period planets is nearly complete.

Which Executive Functioning Deficits Are Associated with AD/HD, ODD/CD and Comorbid AD/HD+ODD/CD? (Attention Deficit/hyperactivity Disorder)(Oppositional Defiant Disorder)

Science.gov (United States)

Oosterlaan, Jaap; Scheres, Anouk; Sergeant, Joseph A.

2005-01-01

This study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3) whether a combination of AD/HD and ODD/CD…

HD271791: dynamical versus binary-supernova ejection scenario

Science.gov (United States)

Gvaramadze, V. V.

2009-05-01

The atmosphere of the extremely high-velocity (530-920kms-1) early B-type star HD271791 is enriched in α-process elements, which suggests that this star is a former secondary component of a massive tight binary system and that its surface was polluted by the nucleosynthetic products after the primary star exploded in a supernova. It was proposed that the (asymmetric) supernova explosion unbind the system and that the secondary star (HD271791) was released at its orbital velocity in the direction of Galactic rotation. In this Letter, we show that to explain the Galactic rest-frame velocity of HD271791 within the framework of the binary-supernova scenario, the stellar remnant of the supernova explosion (a =750-1200kms-1. We therefore consider the binary-supernova scenario as highly unlikely and instead propose that HD271791 attained its peculiar velocity in the course of a strong dynamical three- or four-body encounter in the dense core of the parent star cluster. Our proposal implies that by the moment of encounter HD271791 was a member of a massive post-supernova binary.

Radiation injuries of the spinal marrow of rats after irradiation with fast electrons

International Nuclear Information System (INIS)

Bruce-Micah, B.

1973-01-01

Twenty rats were fractionated irradiated on five days of the week with fast electrons of 42 MeV energy with a single dose of 200 r/day. After 1,000 r, 2,000 r, 3,000 r and 4,000 r HD, the animals were supravitally fixed and the spinal marrow was removed. The histological investigation already showed after 1,000 r HD distinct changes of the nerve cells and nerve fibers whereas the vessels appeared not to be injured. After 2,000 r HD, vessel changes with edemas occured for the first time. After 3,000 r HD, all nerve cells were severely injured, the glia tissue was denser and the vessels were enlarged despite endothelial proliferations. Furthermore, there were big edemas around the vessels and a beginning of demyelinisation in the dorsal column. After 4,000 r HD, a great part of the nerve cells and also a few glia cells were destroyed. The remaining glia cells were pyknotic and had partly several nucleoli. The tractus of the white matter consisted almost only now of a glia felt. With a survival time of six weeks, the glia had greatly regenerated and numerous new capillaries had sprouted in the grey matter. The white matter was strongly demyelinised. In the front lateral column, small round necrosis centres were visible. 18 weeks after irradiation, the glia tissue had greatly rebuilt itself. There were only very few nerve cells present. The strong sprouting of new capillaries in the grey matter was most noticeable. The results show that the application of fast electrons is of no advantage as regards injuring the nerve tissue compared to X-rays. (orig./LH) [de

Thermodynamics of dinonylnaphthalene sulfonic acid (HD)

International Nuclear Information System (INIS)

Raieh, M.A.; Aly, H.F.

1980-01-01

The effect of temperature on the extraction of the trivalent actinides Am 3+ , Cm 3+ and Cf 3+ with the liquid cation exchanger dinonylnaphtalenesulphonic acid (HD) in toluene is studied. The different thermodynamic functions of this system are determined from the experimental results. It is found that the free energy variation for the extraction of these metal ions by HD is mainly determined by the entropic terms arising from the hydration-dehydration process of the exchanged ions. (author)

Automatic anterior chamber angle assessment for HD-OCT images.

Science.gov (United States)

Tian, Jing; Marziliano, Pina; Baskaran, Mani; Wong, Hong-Tym; Aung, Tin

2011-11-01

Angle-closure glaucoma is a major blinding eye disease and could be detected by measuring the anterior chamber angle in the human eyes. High-definition OCT (Cirrus HD-OCT) is an emerging noninvasive, high-speed, and high-resolution imaging modality for the anterior segment of the eye. Here, we propose a novel algorithm which automatically detects a new landmark, Schwalbe's line, and measures the anterior chamber angle in the HD-OCT images. The distortion caused by refraction is corrected by dewarping the HD-OCT images, and three biometric measurements are defined to quantitatively assess the anterior chamber angle. The proposed algorithm was tested on 40 HD-OCT images of the eye and provided accurate measurements in about 1 second.

ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS

Energy Technology Data Exchange (ETDEWEB)

Lissauer, Jack J.; Rowe, Jason F.; Bryson, Stephen T.; Howell, Steve B.; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Marcy, Geoffrey W. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Adams, Elisabeth; Fressin, Francois; Geary, John; Holman, Matthew J.; Ragozzine, Darin [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Buchhave, Lars A. [Niels Bohr Institute, University of Copenhagen, DK-2100, Copenhagen (Denmark); Ciardi, David R. [Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Cochran, William D. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Ford, Eric B.; Morehead, Robert C. [University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Gilliland, Ronald L., E-mail: Jack.Lissauer@nasa.gov [Space Telescope Science Institute, Baltimore, MD 21218 (United States); and others

2012-05-10

We present a statistical analysis that demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) indeed represent true, physically associated transiting planets. Binary stars provide the primary source of false positives among Kepler planet candidates, implying that false positives should be nearly randomly distributed among Kepler targets. In contrast, true transiting planets would appear clustered around a smaller number of Kepler targets if detectable planets tend to come in systems and/or if the orbital planes of planets encircling the same star are correlated. There are more than one hundred times as many Kepler planet candidates in multi-candidate systems as would be predicted from a random distribution of candidates, implying that the vast majority are true planets. Most of these multis are multiple-planet systems orbiting the Kepler target star, but there are likely cases where (1) the planetary system orbits a fainter star, and the planets are thus significantly larger than has been estimated, or (2) the planets orbit different stars within a binary/multiple star system. We use the low overall false-positive rate among Kepler multis, together with analysis of Kepler spacecraft and ground-based data, to validate the closely packed Kepler-33 planetary system, which orbits a star that has evolved somewhat off of the main sequence. Kepler-33 hosts five transiting planets, with periods ranging from 5.67 to 41 days.

Observsational Planet Formation

Science.gov (United States)

Dong, Ruobing; Zhu, Zhaohuan; Fung, Jeffrey

2017-06-01

Planets form in gaseous protoplanetary disks surrounding newborn stars. As such, the most direct way to learn how they form from observations, is to directly watch them forming in disks. In the past, this was very difficult due to a lack of observational capabilities; as such, planet formation was largely a subject of pure theoretical astrophysics. Now, thanks to a fleet of new instruments with unprecedented resolving power that have come online recently, we have just started to unveil features in resolve images of protoplanetary disks, such as gaps and spiral arms, that are most likely associated with embedded (unseen) planets. By comparing observations with theoretical models of planet-disk interactions, the masses and orbits of these still forming planets may be constrained. Such planets may help us to directly test various planet formation models. This marks the onset of a new field — observational planet formation. I will introduce the current status of this field.

White dwarf planets

Directory of Open Access Journals (Sweden)

Bonsor Amy

2013-04-01

Full Text Available The recognition that planets may survive the late stages of stellar evolution, and the prospects for finding them around White Dwarfs, are growing. We discuss two aspects governing planetary survival through stellar evolution to the White Dwarf stage. First we discuss the case of a single planet, and its survival under the effects of stellar mass loss, radius expansion, and tidal orbital decay as the star evolves along the Asymptotic Giant Branch. We show that, for stars initially of 1 − 5 M⊙, any planets within about 1 − 5 AU will be engulfed, this distance depending on the stellar and planet masses and the planet's eccentricity. Planets engulfed by the star's envelope are unlikely to survive. Hence, planets surviving the Asymptotic Giant Branch phase will probably be found beyond ∼ 2 AU for a 1  M⊙ progenitor and ∼ 10 AU for a 5 M⊙ progenitor. We then discuss the evolution of two-planet systems around evolving stars. As stars lose mass, planet–planet interactions become stronger, and many systems stable on the Main Sequence become destabilised following evolution of the primary. The outcome of such instabilities is typically the ejection of one planet, with the survivor being left on an eccentric orbit. These eccentric planets could in turn be responsible for feeding planetesimals into the neighbourhood of White Dwarfs, causing observed pollution and circumstellar discs.

THE FIRST PLANETS: THE CRITICAL METALLICITY FOR PLANET FORMATION

International Nuclear Information System (INIS)

Johnson, Jarrett L.; Li Hui

2012-01-01

A rapidly growing body of observational results suggests that planet formation takes place preferentially at high metallicity. In the core accretion model of planet formation this is expected because heavy elements are needed to form the dust grains which settle into the midplane of the protoplanetary disk and coagulate to form the planetesimals from which planetary cores are assembled. As well, there is observational evidence that the lifetimes of circumstellar disks are shorter at lower metallicities, likely due to greater susceptibility to photoevaporation. Here we estimate the minimum metallicity for planet formation, by comparing the timescale for dust grain growth and settling to that for disk photoevaporation. For a wide range of circumstellar disk models and dust grain properties, we find that the critical metallicity above which planets can form is a function of the distance r at which the planet orbits its host star. With the iron abundance relative to that of the Sun [Fe/H] as a proxy for the metallicity, we estimate a lower limit for the critical abundance for planet formation of [Fe/H] crit ≅ –1.5 + log (r/1 AU), where an astronomical unit (AU) is the distance between the Earth and the Sun. This prediction is in agreement with the available observational data, and carries implications for the properties of the first planets and for the emergence of life in the early universe. In particular, it implies that the first Earth-like planets likely formed from circumstellar disks with metallicities Z ∼> 0.1 Z ☉ . If planets are found to orbit stars with metallicities below the critical metallicity, this may be a strong challenge to the core accretion model.

Limits On Undetected Planets in the Six Transiting Planets Kepler-11 System

Science.gov (United States)

Lissauer, Jack

2017-01-01

The Kepler-11 has five inner planets ranging from approx. 2 - 1 times as massive Earth in a tightly-packed configuration, with orbital periods between 10 and 47 days. A sixth planet, Kepler-11 g, with a period of118 days, is also observed. The spacing between planets Kepler-11 f and Kepler-11 g is wide enough to allow room for a planet to orbit stably between them. We compare six and seven planet fits to measured transit timing variations (TTVs) of the six known planets. We find that in most cases an additional planet between Kepler-11 f and Kepler-11 g degrades rather than enhances the fit to the TTV data, and where the fit is improved, the improvement provides no significant evidence of a planet between Kepler-11 f and Kepler-11 g. This implies that any planet in this region must be low in mass. We also provide constraints on undiscovered planets orbiting exterior to Kepler-11 g. representations will be described.

NV-CMOS HD camera for day/night imaging

Science.gov (United States)

Vogelsong, T.; Tower, J.; Sudol, Thomas; Senko, T.; Chodelka, D.

2014-06-01

SRI International (SRI) has developed a new multi-purpose day/night video camera with low-light imaging performance comparable to an image intensifier, while offering the size, weight, ruggedness, and cost advantages enabled by the use of SRI's NV-CMOS HD digital image sensor chip. The digital video output is ideal for image enhancement, sharing with others through networking, video capture for data analysis, or fusion with thermal cameras. The camera provides Camera Link output with HD/WUXGA resolution of 1920 x 1200 pixels operating at 60 Hz. Windowing to smaller sizes enables operation at higher frame rates. High sensitivity is achieved through use of backside illumination, providing high Quantum Efficiency (QE) across the visible and near infrared (NIR) bands (peak QE camera, which operates from a single 5V supply. The NVCMOS HD camera provides a substantial reduction in size, weight, and power (SWaP) , ideal for SWaP-constrained day/night imaging platforms such as UAVs, ground vehicles, fixed mount surveillance, and may be reconfigured for mobile soldier operations such as night vision goggles and weapon sights. In addition the camera with the NV-CMOS HD imager is suitable for high performance digital cinematography/broadcast systems, biofluorescence/microscopy imaging, day/night security and surveillance, and other high-end applications which require HD video imaging with high sensitivity and wide dynamic range. The camera comes with an array of lens mounts including C-mount and F-mount. The latest test data from the NV-CMOS HD camera will be presented.

Planet Detection: The Kepler Mission

Science.gov (United States)

Jenkins, Jon M.; Smith, Jeffrey C.; Tenenbaum, Peter; Twicken, Joseph D.; Van Cleve, Jeffrey

2012-03-01

The search for exoplanets is one of the hottest topics in astronomy and astrophysics in the twenty-first century, capturing the public's attention as well as that of the astronomical community. This nascent field was conceived in 1989 with the discovery of a candidate planetary companion to HD114762 [35] and was born in 1995 with the discovery of the first extrasolar planet 51 Peg-b [37] orbiting a main sequence star. As of March, 2011, over 500 exoplanets have been discovered* and 106 are known to transit or cross their host star, as viewed from Earth. Of these transiting planets, 15 have been announced by the Kepler Mission, which was launched into an Earth-trailing, heliocentric orbit in March, 2009 [1,4,6,15,18,20,22,31,32,34,36,43]. In addition, over 1200 candidate transiting planets have already been detected by Kepler [5], and vigorous follow-up observations are being conducted to vet these candidates. As the false-positive rate for Kepler is expected to be quite low [39], Kepler has effectively tripled the number of known exoplanets. Moreover, Kepler will provide an unprecedented data set in terms of photometric precision, duration, contiguity, and number of stars. Kepler's primary science objective is to determine the frequency of Earth-size planets transiting their Sun-like host stars in the habitable zone, that range of orbital distances for which liquid water would pool on the surface of a terrestrial planet such as Earth, Mars, or Venus. This daunting task demands an instrument capable of measuring the light output from each of over 100,000 stars simultaneously with an unprecedented photometric precision of 20 parts per million (ppm) at 6.5-h intervals. The large number of stars is required because the probability of the geometrical alignment of planetary orbits that permit observation of transits is the ratio of the size of the star to the size of the planetary orbit. For Earth-like planets in 1-astronomical unit (AU) orbits† about sun-like stars

The Scattering Outcomes of Kepler Circumbinary Planets: Planet Mass Ratio

Energy Technology Data Exchange (ETDEWEB)

Gong, Yan-Xiang; Ji, Jianghui, E-mail: yxgong@pmo.ac.cn, E-mail: jijh@pmo.ac.cn [CAS Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2017-11-01

Recent studies reveal that the free eccentricities of Kepler-34b and Kepler-413b are much larger than their forced eccentricities, implying that scattering events may take place in their formation. The observed orbital configuration of Kepler-34b cannot be well reproduced in disk-driven migration models, whereas a two-planet scattering scenario can play a significant role of shaping the planetary configuration. These studies indicate that circumbinary planets discovered by Kepler may have experienced scattering process. In this work, we extensively investigate the scattering outcomes of circumbinary planets focusing on the effects of planet mass ratio . We find that the planetary mass ratio and the the initial relative locations of planets act as two important parameters that affect the eccentricity distribution of the surviving planets. As an application of our model, we discuss the observed orbital configurations of Kepler-34b and Kepler-413b. We first adopt the results from the disk-driven models as the initial conditions, then simulate the scattering process that occurs in the late evolution stage of circumbinary planets. We show that the present orbital configurations of Kepler-34b and Kepler-413b can be well reproduced when considering a two unequal-mass planet ejection model. Our work further suggests that some of the currently discovered circumbinary single-planet systems may be survivors of original multiple-planet systems. The disk-driven migration and scattering events occurring in the late stage both play an irreplaceable role in sculpting the final systems.

Polarized proton and deuteron solid HD targets

International Nuclear Information System (INIS)

Honig, A.

1977-01-01

A decade has now elapsed since HD was proposed as a polarized proton and deuteron target with exceptionally desirable properties. These include a very high free proton proportion, independently polarizable proton and deuteron systems, and a ''frozen-spin'' mode of operation which allows separation of the functions of production and utilization of the highly polarized target. A discussion is given of what can be expected of the polarized HD system right now, without further research. The basic features of solid HD pertinent to its use as a ''frozen-spin'' target are outlined, then a summary is given of the particular experimental results which support the contention that the target will perform successfully, and finally, some feasible operating modes and the expected performances from them are presented

Datablock: hd141

Indian Academy of Sciences (India)

2016-01-15

Jan 15, 2016 ... checkCIF/PLATON page 2 http://checkcif.iucr.org/cgibin/checkcif_hkl.pl. 1/3. checkCIF (basic structural check) running. checkCIF/PLATON (basic structural check). Structure factors have been supplied for datablock(s) hd141. THIS REPORT IS FOR GUIDANCE ONLY. IF USED AS PART OF A REVIEW.

Extrasolar planets: constraints for planet formation models.

Science.gov (United States)

Santos, Nuno C; Benz, Willy; Mayor, Michel

2005-10-14

Since 1995, more than 150 extrasolar planets have been discovered, most of them in orbits quite different from those of the giant planets in our own solar system. The number of discovered extrasolar planets demonstrates that planetary systems are common but also that they may possess a large variety of properties. As the number of detections grows, statistical studies of the properties of exoplanets and their host stars can be conducted to unravel some of the key physical and chemical processes leading to the formation of planetary systems.

HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS

International Nuclear Information System (INIS)

Hinkel, Natalie R.; Kane, Stephen R.

2013-01-01

Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets μ Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery

HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS

Energy Technology Data Exchange (ETDEWEB)

Hinkel, Natalie R.; Kane, Stephen R., E-mail: natalie.hinkel@gmail.com [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2013-09-01

Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets {mu} Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery.

Variability in the pre-transit signal of HD 189733 b

Science.gov (United States)

Cauley, Paul W.; Redfield, Seth; Jensen, Adam G.; Barman, Travis; Endl, Michael; Cochran, William D.

2016-01-01

Hot planets, i.e., those with orbital periods of a few days, can interact strongly with their host stars via gravitational tides, magnetic interactions, or via collisions between planetary and stellar winds or the planetary magnetosphere and the stellar wind. Recently, pre-transit absorption signals, caused by material orbiting ahead of the planet, have been detected around a handful of exoplanets. Two of these measurements, those for WASP-12 b (Llama et al. 2011) and HD 189733 b (Cauley et al. 2015), were interpreted as being the result of compressed material in a bow shock formed by the planetary magnetosphere plowing through the stellar wind. These signals are expected to be variable at some level as the planet passes through an inhomogenous stellar wind or corona and stellar activity levels change. To investigate this potential variability and confirm the detected signal, we have recently obtained followup observations to the 2013 transit reported in Cauley et al. (2015). The new measurements confirm the existence of the pre- and in-transit absorption detected in the 2013 data. However, the new signal is not consistent with the specific bow shock geometry presented in Cauley et al. (2015). We have performed a more detailed examination of the Ca II H and K line core flux, which is a proxy for the stellar activity level, for the 2013 data. We find a weak correlation between the Hα core flux and the Ca II core flux, suggesting that some, but not all, of the pre-transit absorption signature may be a result of changing stellar activity levels during the observations. Our examination of the Ca II core flux measurements uncover variability that is not seen using the SHK activity index. We are evaluating techniques to calibrate our Hα signal with these more detailed Ca II measurements and suggest that the core flux is a better proxy of low level stellar variability for a single epoch. In addition, the 2015 transit confirms that pre-transit absorption signals are

The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453

Energy Technology Data Exchange (ETDEWEB)

Long, Zachary C.; Fernandes, Rachel B.; Sitko, Michael [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Wagner, Kevin [Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Muto, Takayuki [Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo, 163-8677 (Japan); Hashimoto, Jun; Oh, Daehyon; Tamura, Motohide; Yang, Yi [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Follette, Katherine [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer Street, Suite 100, Oakland CA 96402 (United States); Fukagawa, Misato [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya (Japan); Hasegawa, Yasuhiro [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Kluska, Jacques; Kraus, Stefan [University of Exeter Astrophysics Group, School of Physics, Stocker Road, Exeter, Devon EX4 4QL (United Kingdom); Mayama, Satoshi [Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); McElwain, Michael W. [Exoplanets and Stellar Astrophysics Laboratory, Code 667, NASA’s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Uyama, Taichi [Department of Astronomy and RESCUE, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Wisniewski, John P. [Homer L. Dodge Department of Physics, University of Oklahoma, Norman, OK 73071 (United States)

2017-03-20

We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y , J , and K 1 bands that reveals an inner gap (9–18 au), an outer disk (18–39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45°) and their major axes, PA = 140° east of north for the outer disk, and 100° for the inner disk. We find an outer-disk inclination of 25° ± 10° from face-on, in broad agreement with the Wagner et al. measurement of 34°. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.

The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453

Science.gov (United States)

Long, Zachary C.; Fernandes, Rachel B.; Sitko, Michael; Wagner, Kevin; Muto, Takayuki; Hashimoto, Jun; Follette, Katherine; Grady, Carol A.; Fukagawa, Misato; Hasegawa, Yasuhiro; Kluska, Jacques; Kraus, Stefan; Mayama, Satoshi; McElwain, Michael W.; Oh, Daehyon; Tamura, Motohide; Uyama, Taichi; Wisniewski, John P.; Yang, Yi

2017-03-01

We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y, J, and K1 bands that reveals an inner gap (9-18 au), an outer disk (18-39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45°) and their major axes, PA = 140° east of north for the outer disk, and 100° for the inner disk. We find an outer-disk inclination of 25° ± 10° from face-on, in broad agreement with the Wagner et al. measurement of 34°. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.

Origins and Destinations: Tracking Planet Composition through Planet Formation Simulations

Science.gov (United States)

Chance, Quadry; Ballard, Sarah

2018-01-01

There are now several thousand confirmed exoplanets, a number which far exceeds our resources to study them all in detail. In particular, planets around M dwarfs provide the best opportunity for in-depth study of their atmospheres by telescopes in the near future. The question of which M dwarf planets most merit follow-up resources is a pressing one, given that NASA’s TESS mission will soon find hundreds of such planets orbiting stars bright enough for both ground and spaced-based follow-up.Our work aims to predict the approximate composition of planets around these stars through n-body simulations of the last stage of planet formation. With a variety of initial disk conditions, we investigate how the relative abundances of both refractory and volatile compounds in the primordial planetesimals are mapped to the final planet outcomes. These predictions can serve to provide a basis for making an educated guess about (a) which planets to observe with precious resources like JWST and (b) how to identify them based on dynamical clues.

Planet logy : Towards Comparative Planet logy beyond the Solar Earth System

Science.gov (United States)

Khan, A. H.

2011-10-01

Today Scenario planet logy is a very important concept because now days the scientific research finding new and new planets and our work's range becoming too long. In the previous study shows about 10-12 years the research of planet logy now has changed . Few years ago we was talking about Sun planet, Earth planet , Moon ,Mars Jupiter & Venus etc. included but now the time has totally changed the recent studies showed that mono lakes California find the arsenic food use by micro organism that show that our study is very tiny as compare to planet long areas .We have very well known that arsenic is the toxic agent's and the toxic agent's present in the lakes and micro organism developing and life going on it's a unbelievable point for us but nature always play a magical games. In few years ago Aliens was the story no one believe the Aliens origin but now the aliens showed catch by our space craft and shuttle and every one believe that Aliens origin but at the moment's I would like to mention one point's that we have too more work required because our planet logy has a vast field. Most of the time our scientific mission shows that this planet found liquid oxygen ,this planet found hydrogen .I would like to clear that point's that all planet logy depend in to the chemical and these chemical gave the indication of the life but we are not abele to developed the adaptation according to the micro organism . Planet logy compare before study shows that Sun it's a combination of the various gases combination surrounded in a round form and now the central Sun Planets ,moons ,comets and asteroids In other word we can say that Or Sun has a wide range of the physical and Chemical properties in the after the development we can say that all chemical and physical property engaged with a certain environment and form a various contains like asteroids, moon, Comets etc. Few studies shows that other planet life affected to the out living planet .We can assure with the example the life

Phenomena of g-u symmetry-breakdown in HD

NARCIS (Netherlands)

de Lange, A.; Reinhold, E.M.; Ubachs, W.M.G.

2002-01-01

Phenomena associated with the breakdown of inversion symmetry in the HD molecule are reviewed and discussed. A distinction is made between three kinds of physical effects observed in HD spectra. The existence of a small electric dipole moment in the ground state gives rise to vibrational and pure

Habitability of extrasolar planets and tidal spin evolution.

Science.gov (United States)

Heller, René; Barnes, Rory; Leconte, Jérémy

2011-12-01

Stellar radiation has conservatively been used as the key constraint to planetary habitability. We review here the effects of tides, exerted by the host star on the planet, on the evolution of the planetary spin. Tides initially drive the rotation period and the orientation of the rotation axis into an equilibrium state but do not necessarily lead to synchronous rotation. As tides also circularize the orbit, eventually the rotation period does equal the orbital period and one hemisphere will be permanently irradiated by the star. Furthermore, the rotational axis will become perpendicular to the orbit, i.e. the planetary surface will not experience seasonal variations of the insolation. We illustrate here how tides alter the spins of planets in the traditional habitable zone. As an example, we show that, neglecting perturbations due to other companions, the Super-Earth Gl581d performs two rotations per orbit and that any primordial obliquity has been eroded.

Terrestrial planet formation.

Science.gov (United States)

Righter, K; O'Brien, D P

2011-11-29

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS

International Nuclear Information System (INIS)

Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

2010-01-01

We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ('planetesimals'). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M + from 10 to 20 AU. For large planet masses (M ∼> M Sat ), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a ∼ -1 and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with ∼ Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive

Seek a Minor Sun: The Distribution of Habitable Planets in the Hertzsprung-Russell-Rosenberg Diagram

Science.gov (United States)

Gaidos, Eric

2015-07-01

The Sun-Earth systems has long been used as a template to understand habitable planets around other stars and to develop missions to seek them. However, two decades of exoplanet studies have shown that many, if not most planetary systems around G dwarf stars do not resemble the Solar System. Moreover, an objective census of our Galaxy might ignore solar- type stars and focus on M dwarfs, which constitute some 80% of all stars in the neighborhood. Recent work has shown that M dwarfs have more close-in planets than solar-type stars, and perhaps more planets in the "habitable zone" defined by stellar irradiation. M dwarfs also burn hydrogen over a vastly longer time; slow evolution on the main sequence means a planet can remain habitable for much longer, providing a more permissive environment for the evo- lution of life and intelligence. If M dwarfs are such compelling locales to look for life, why are we ourselves not orbiting a red Sun?

The curious case of HD 41248. A pair of static signals buried behind red noise

Energy Technology Data Exchange (ETDEWEB)

Jenkins, J. S.; Tuomi, M., E-mail: jjenkins@das.uchile.cl [Departamento de Astronomia, Universidad de Chile, Camino el Observatorio 1515, Las Condes, Santiago, Casilla 36-D (Chile)

2014-10-20

Gaining a better understanding of the effects of stellar-induced radial velocity noise is critical for the future of exoplanet studies since the discovery of the lowest-mass planets using this method will require us to go below the intrinsic stellar noise limit. An interesting test case in this respect is that of the southern solar analog HD 41248. The radial velocity time series of this star has been proposed to contain either a pair of signals with periods of around 18 and 25 days, which could be due to a pair of resonant super-Earths, or a single and varying 25 day signal that could arise due to a complex interplay between differential rotation and modulated activity. In this work, we build up more evidence for the former scenario, showing that the signals are still clearly significant, even after more than 10 yr of observations, and they likely do not change in period, amplitude, or phase as a function of time, the hallmarks of static Doppler signals. We show that over the last two observing seasons, this star was more intrinsically active and the noise reddened, highlighting why better noise models are needed to find the lowest amplitude signals, in particular, models that consider noise correlations. This analysis shows that there is still sufficient evidence for the existence of two super-Earths on the edge of, or locked into, a 7:5 mean motion resonance orbiting HD 41248.

Mitochondrial fragmentation in neuronal degeneration: Toward an understanding of HD striatal susceptibility

International Nuclear Information System (INIS)

Cherubini, Marta; Ginés, Silvia

2017-01-01

Huntington's disease (HD) is an autosomal-dominant progressive neurodegenerative disorder that primarily affects medium spiny neurons within the striatum. HD is caused by inheritance of an expanded CAG repeat in the HTT gene, resulting in a mutant huntingtin (mHtt) protein containing extra glutamine residues. Despite the advances in understanding the molecular mechanisms involved in HD the preferential vulnerability of the striatum remains an intriguing question. This review discusses current knowledge that links altered mitochondrial dynamics with striatal susceptibility in HD. We also highlight how the modulation of mitochondrial function may constitute an attractive therapeutic approach to reduce mHtt-induced toxicity and therefore prevent the selective striatal neurodegeneration. - Highlights: • Mitochondrial dynamics is unbalanced towards fission in HD. • Excessive mitochondrial fragmentation plays a critical role in the selective vulnerability of the striatum in HD. • Therapeutic approaches aimed to inhibit mitochondrial fission could contribute to prevent striatal neurodegeneration in HD.

Astrometry, Radial Velocity, and Photometry: The HD 128311 System Remixed with Data from HST, HET, and APT

Science.gov (United States)

McArthur, Barbara. E.; Benedict, G. Fritz; Henry, Gregory W.; Hatzes, Artie; Cochran, William D.; Harrison, Tom E.; Johns-Krull, Chris; Nelan, Ed

2014-11-01

We have used high-cadence radial velocity measurements from the Hobby-Eberly Telescope with published velocities from the Lick 3 m Shane Telescope, combined with astrometric data from the Hubble Space Telescope (HST) Fine Guidance Sensors to refine the orbital parameters of the HD 128311 system, and determine an inclination of 55.°95 ± 14.°55 and true mass of 3.789 +0.924 -0.432 M JUP for HD 128311 c. The combined radial velocity data also reveal a short period signal which could indicate a third planet in the system with an Msin i of 0.133 ± 0.005 M JUP or stellar phenomena. Photometry from the T12 0.8 m automatic photometric telescope at the Fairborn Observatory and HST are used to determine a photometric period close to, but not within the errors of the radial velocity signal. We performed a cross-correlation bisector analysis of the radial velocity data to look for correlations with the photometric period and found none. Dynamical integrations of the proposed system show long-term stability with the new orbital parameters of over 10 million years. Our new orbital elements do not support the claims of HD 128311 b and c being in mean motion resonance. Based 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 NAS5-26555. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen, and observations with T12 0.8 m automatic photoelectric telescope (APT) at Fairborn Observatory.

Planet traps and first planets: The critical metallicity for gas giant formation

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Yasuhiro; Hirashita, Hiroyuki, E-mail: yasu@asiaa.sinica.edu.tw, E-mail: hirashita@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), P.O. Box 23-141, Taipei 10617, Taiwan (China)

2014-06-10

The ubiquity of planets poses an interesting question: when are first planets formed in galaxies? We investigate this by adopting a theoretical model where planet traps are combined with the standard core accretion scenario in which the efficiency of forming planetary cores directly relates to the metallicity ([Fe/H]) in disks. Three characteristic exoplanetary populations are examined: hot Jupiters, exo-Jupiters around 1 AU, and low-mass planets in tight orbits, such as super-Earths. We statistically compute planet formation frequencies (PFFs), as well as the orbital radius (〈R{sub rapid}〉) within which gas accretion becomes efficient enough to form Jovian planets, as a function of metallicity (–2 ≤ [Fe/H] ≤–0.6). We show that the total PFFs for these three populations increase steadily with metallicity. This is the direct outcome of the core accretion picture. For the metallicity range considered here, the population of low-mass planets dominates Jovian planets. The Jovian planets contribute to the PFFs above [Fe/H] ≅ –1. We find that the hot Jupiters form more efficiently than the exo-Jupiters at [Fe/H] ≲ –0.7. This arises from the slower growth of planetary cores and their more efficient radial inward transport by the host traps in lower metallicity disks. We show that the critical metallicity for forming Jovian planets is [Fe/H] ≅ –1.2 by comparing 〈R{sub rapid}〉 of hot Jupiters and low-mass planets. The comparison intrinsically links to the different gas accretion efficiency between these two types of planets. Therefore, this study implies that important physical processes in planet formation may be tested by exoplanet observations around metal-poor stars.

Planet traps and first planets: The critical metallicity for gas giant formation

International Nuclear Information System (INIS)

Hasegawa, Yasuhiro; Hirashita, Hiroyuki

2014-01-01

The ubiquity of planets poses an interesting question: when are first planets formed in galaxies? We investigate this by adopting a theoretical model where planet traps are combined with the standard core accretion scenario in which the efficiency of forming planetary cores directly relates to the metallicity ([Fe/H]) in disks. Three characteristic exoplanetary populations are examined: hot Jupiters, exo-Jupiters around 1 AU, and low-mass planets in tight orbits, such as super-Earths. We statistically compute planet formation frequencies (PFFs), as well as the orbital radius (〈R rapid 〉) within which gas accretion becomes efficient enough to form Jovian planets, as a function of metallicity (–2 ≤ [Fe/H] ≤–0.6). We show that the total PFFs for these three populations increase steadily with metallicity. This is the direct outcome of the core accretion picture. For the metallicity range considered here, the population of low-mass planets dominates Jovian planets. The Jovian planets contribute to the PFFs above [Fe/H] ≅ –1. We find that the hot Jupiters form more efficiently than the exo-Jupiters at [Fe/H] ≲ –0.7. This arises from the slower growth of planetary cores and their more efficient radial inward transport by the host traps in lower metallicity disks. We show that the critical metallicity for forming Jovian planets is [Fe/H] ≅ –1.2 by comparing 〈R rapid 〉 of hot Jupiters and low-mass planets. The comparison intrinsically links to the different gas accretion efficiency between these two types of planets. Therefore, this study implies that important physical processes in planet formation may be tested by exoplanet observations around metal-poor stars.

Spitzer/MIPS 24 {mu}m OBSERVATIONS OF HD 209458b: THREE ECLIPSES, TWO AND A HALF TRANSITS, AND A PHASE CURVE CORRUPTED BY INSTRUMENTAL SENSITIVITY VARIATIONS

Energy Technology Data Exchange (ETDEWEB)

Crossfield, Ian J. M. [Department of Physics, and Astronomy, University of California, Los Angeles, CA 90095 (United States); Knutson, Heather [Caltech Division of Geological and Planetary Sciences, Pasadena, CA 91125 (United States); Fortney, Jonathan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Cowan, Nicolas B. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Deming, Drake, E-mail: ianc@astro.ucla.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

2012-06-20

We report the results of an analysis of all Spitzer/MIPS 24 {mu}m observations of HD 209458b, one of the touchstone objects in the study of irradiated giant planet atmospheres. Altogether, we analyze two and a half transits, three eclipses, and a 58 hr near-continuous observation designed to detect the planet's thermal phase curve. The results of our analysis are: (1) a mean transit depth of 1.484% {+-} 0.033%, consistent with previous measurements and showing no evidence of variability in transit depth at the 3% level. (2) A mean eclipse depth of 0.338% {+-} 0.026%, somewhat higher than that previously reported for this system; this new value brings observations into better agreement with models. From this eclipse depth we estimate an average dayside brightness temperature of 1320 {+-} 80 K; the dayside flux shows no evidence of variability at the 12% level. (3) Eclipses in the system occur 32 {+-} 129 s earlier than would be expected from a circular orbit, which constrains the orbital quantity ecos {omega} to be 0.00004 {+-} 0.00033. This result is fully consistent with a circular orbit and sets an upper limit of 140 m s{sup -1} (3{sigma}) on any eccentricity-induced velocity offset during transit. The phase curve observations (including one of the transits) exhibit an anomalous trend similar to the detector ramp seen in previous Spitzer/IRAC observations; by modeling this ramp we recover the system parameters for this transit. The long-duration photometry which follows the ramp and transit exhibits a gradual {approx}0.2% decrease in flux over {approx}30 hr. This effect is similar to that seen in pre-launch calibration data taken with the 24 {mu}m array and is better fit by an instrumental model than a model invoking planetary emission. The large uncertainties associated with this poorly understood, likely instrumental effect prevent us from usefully constraining the planet's thermal phase curve. Our observations highlight the need for a thorough

NBM-HD-1: A Novel Histone Deacetylase Inhibitor with Anticancer Activity

Directory of Open Access Journals (Sweden)

Wei-Jan Huang

2012-01-01

Full Text Available HDAC inhibitors (HDACis have been developed as promising anticancer agents in recent years. In this study, we synthesized and characterized a novel HDACi, termed NBM-HD-1. This agent was derived from the semisynthesis of propolin G, isolated from Taiwanese green propolis (TGP, and was shown to be a potent suppressor of tumor cell growth in human breast cancer cells (MCF-7 and MDA-MB-231 and rat glioma cells (C6, with an IC50 ranging from 8.5 to 10.3 μM. Western blot demonstrated that levels of p21(Waf1/Cip1, gelsolin, Ac-histone 4, and Ac-tubulin markedly increased after treatment of cancer cells with NBM-HD-1. After NBM-HD-1 treatment for 1–4 h, p-PTEN and p-AKT levels were markedly decreased. Furthermore, we also found the anticancer activities of NBM-HD-1 in regulating cell cycle regulators. Treatment with NBM-HD-1, p21(Waf1/Cip1 gene expression had markedly increased while cyclin B1 and D1 gene expressions had markedly decreased. On the other hand, we found that NBM-HD-1 increased the expressions of tumor-suppressor gene p53 in a dose-dependent manner. Finally, we showed that NBM-HD-1 exhibited potent antitumor activity in a xenograft model. In conclusion, this study demonstrated that this compound, NBM-HD-1, is a novel and potent HDACi with anticancer activity in vitro and in vivo.

PLANET-PLANET SCATTERING LEADS TO TIGHTLY PACKED PLANETARY SYSTEMS

International Nuclear Information System (INIS)

Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

2009-01-01

The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masses, the mass-inclination degeneracy does not significantly affect our results. We consider a wide range of initial planetary mass distributions and find that some are poor fits to the observed systems. In fact, many of our scattering experiments overproduce systems very close to the stability boundary. The distribution of dynamical configurations of two-planet systems may provide better discrimination between scattering models than the distribution of eccentricity. Our results imply that, at least in their inner regions which are weakly affected by gas or planetesimal disks, planetary systems should be 'packed', with no large gaps between planets.

Planet-planet scattering leads to tightly packed planetary systems

OpenAIRE

Raymond, Sean N.; Barnes, Rory; Veras, Dimitri; Armitage, Philip J.; Gorelick, Noel; Greenberg, Richard

2009-01-01

The known extrasolar multiple-planet systems share a surprising dynamical attribute: they cluster just beyond the Hill stability boundary. Here we show that the planet-planet scattering model, which naturally explains the observed exoplanet eccentricity distribution, can reproduce the observed distribution of dynamical configurations. We calculated how each of our scattered systems would appear over an appropriate range of viewing geometries; as Hill stability is weakly dependent on the masse...

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

Energy Technology Data Exchange (ETDEWEB)

Ranjan, Sukrit; Sasselov, Dimitar D. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Wordsworth, Robin, E-mail: sranjan@cfa.harvard.edu [Harvard Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02140 (United States)

2017-07-10

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UV environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

Science.gov (United States)

Ranjan, Sukrit; Wordsworth, Robin; Sasselov, Dimitar D.

2017-07-01

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UV environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

International Nuclear Information System (INIS)

Ranjan, Sukrit; Sasselov, Dimitar D.; Wordsworth, Robin

2017-01-01

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UV environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.

Influence of stellar multiplicity on planet formation. I. Evidence of suppressed planet formation due to stellar companions within 20 au and validation of four planets from the Kepler multiple planet candidates

International Nuclear Information System (INIS)

Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei; Barclay, Thomas

2014-01-01

The planet occurrence rate for multiple stars is important in two aspects. First, almost half of stellar systems in the solar neighborhood are multiple systems. Second, the comparison of the planet occurrence rate for multiple stars to that for single stars sheds light on the influence of stellar multiplicity on planet formation and evolution. We developed a method of distinguishing planet occurrence rates for single and multiple stars. From a sample of 138 bright (K P < 13.5) Kepler multi-planet candidate systems, we compared the stellar multiplicity rate of these planet host stars to that of field stars. Using dynamical stability analyses and archival Doppler measurements, we find that the stellar multiplicity rate of planet host stars is significantly lower than field stars for semimajor axes less than 20 AU, suggesting that planet formation and evolution are suppressed by the presence of a close-in companion star at these separations. The influence of stellar multiplicity at larger separations is uncertain because of search incompleteness due to a limited Doppler observation time baseline and a lack of high-resolution imaging observation. We calculated the planet confidence for the sample of multi-planet candidates and find that the planet confidences for KOI 82.01, KOI 115.01, KOI 282.01, and KOI 1781.02 are higher than 99.7% and thus validate the planetary nature of these four planet candidates. This sample of bright Kepler multi-planet candidates with refined stellar and orbital parameters, planet confidence estimation, and nearby stellar companion identification offers a well-characterized sample for future theoretical and observational study.

Comparative ionospheres: Terrestrial and giant planets

Science.gov (United States)

Mendillo, Michael; Trovato, Jeffrey; Moore, Luke; Müller-Wodarg, Ingo

2018-03-01

The study of planetary ionospheres within our solar system offers a variety of settings to probe mechanisms of photo-ionization, chemical loss, and plasma transport. Ionospheres are a minor component of upper atmospheres, and thus their mix of ions observed depends on the neutral gas composition of their parent atmospheres. The same solar irradiance (x-rays and extreme-ultra-violet vs. wavelength) impinges upon each of these atmospheres, with solar flux magnitudes changed only by the inverse square of distance from the Sun. If all planets had the same neutral atmosphere-with ionospheres governed by photochemical equilibrium (production = loss)-their peak electron densities would decrease as the inverse of distance from the Sun, and any changes in solar output would exhibit coherent effects throughout the solar system. Here we examine the outer planet with the most observations of its ionosphere (Saturn) and compare its patterns of electron density with those at Earth under the same-day solar conditions. We show that, while the average magnitudes of the major layers of molecular ions at Earth and Saturn are approximately in accord with distance effects, only minor correlations exist between solar effects and day-to-day electron densities. This is in marked contrast to the strong correlations found between the ionospheres of Earth and Mars. Moreover, the variability observed for Saturn's ionosphere (maximum electron density and total electron content) is much larger than found at Earth and Mars. With solar irradiance changes far too small to cause such effects, we use model results to explore the roles of other agents. We find that water sources from Enceladus at low latitudes, and 'ring rain' at middle latitudes, contribute substantially to variability via water ion chemistry. Thermospheric winds and electrodynamics generated at auroral latitudes are suggested causes of high latitude ionospheric variability, but remain inconclusive due to the lack of relevant

A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

International Nuclear Information System (INIS)

Johnson, B. C.; Melosh, H. J.; Lisse, C. M.; Chen, C. H.; Wyatt, M. C.; Thebault, P.; Henning, W. G.; Gaidos, E.; Elkins-Tanton, L. T.; Bridges, J. C.; Morlok, A.

2012-01-01

Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10 19 kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at ∼6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that ∼10 47 molecules of SiO vapor are needed to explain an emission feature at ∼8 μm in the Spitzer IRS spectrum of HD 172555. We find that unless there are ∼10 48 atoms or 0.05 M ⊕ of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the ∼8 μm feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. I. MEASURING PHOTOMETRIC ECCENTRICITIES OF INDIVIDUAL TRANSITING PLANETS

International Nuclear Information System (INIS)

Dawson, Rebekah I.; Johnson, John Asher

2012-01-01

Exoplanet orbital eccentricities offer valuable clues about the history of planetary systems. Eccentric, Jupiter-sized planets are particularly interesting: they may link the 'cold' Jupiters beyond the ice line to close-in hot Jupiters, which are unlikely to have formed in situ. To date, eccentricities of individual transiting planets primarily come from radial-velocity measurements. Kepler has discovered hundreds of transiting Jupiters spanning a range of periods, but the faintness of the host stars precludes radial-velocity follow-up of most. Here, we demonstrate a Bayesian method of measuring an individual planet's eccentricity solely from its transit light curve using prior knowledge of its host star's density. We show that eccentric Jupiters are readily identified by their short ingress/egress/total transit durations—part of the 'photoeccentric' light curve signature of a planet's eccentricity—even with long-cadence Kepler photometry and loosely constrained stellar parameters. A Markov Chain Monte Carlo exploration of parameter posteriors naturally marginalizes over the periapse angle and automatically accounts for the transit probability. To demonstrate, we use three published transit light curves of HD 17156 b to measure an eccentricity of e = 0.71 +0.16 –0.09 , in good agreement with the discovery value e = 0.67 ± 0.08 based on 33 radial-velocity measurements. We present two additional tests using Kepler data. In each case, the technique proves to be a viable method of measuring exoplanet eccentricities and their confidence intervals. Finally, we argue that this method is the most efficient, effective means of identifying the extremely eccentric, proto-hot Jupiters predicted by Socrates et al.

Quality of Life in Prodromal HD: Qualitative Analyses of Discourse from Participants and Companions

Directory of Open Access Journals (Sweden)

Rebecca E. Ready

2011-01-01

Full Text Available Persons who are at risk for Huntington's Disease (HD can be tested for the HD gene expansion before symptom onset. People with the gene expansion, but no clinical diagnosis, are in the prodromal phase of HD. This study explored quality of life (QOL in prodromal HD. Interviews about QOL, conducted with 9 prodromal HD participants and 6 companions, were transcribed. Discourse was coded for emotional valence, content (e.g., coping, spirituality, interpersonal relationships, HD in others, and employment, and time frame (e.g., current, past, and future. Respondents were more positive than negative about the present, which was their major focus. The most common statements were about positive attitudes. Positive statements were made about spirituality, and negative statements were made about HD in other people. Relationships, employment, and coping with HD reflected both positivity and negativity. Participants and companions spoke of the future with different concerns. Applicability of findings to the clinical management of HD are discussed.

MID-INFRARED HIGH-CONTRAST IMAGING OF HD 114174 B: AN APPARENT AGE DISCREPANCY IN A ''SIRIUS-LIKE'' BINARY SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Matthews, Christopher T.; Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Skemer, Andrew; Hinz, Philip M.; Bailey, Vanessa P.; Defrere, Denis; Leisenring, Jarron [Department of Astronomy, University of Arizona, 993 N. Cherry Ave, Tucson, AZ 85721 (United States); Gianninas, Alexandros; Kilic, Mukremin [Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Skrutskie, Michael [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Esposito, Simone; Puglisi, Alfio [Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Arcetri Largo E. Fermi I-550125 Firenze (Italy)

2014-03-10

We present new observations of the faint ''Sirius-like'' companion discovered to orbit HD 114174. Previous attempts to image HD 114174 B at mid-infrared wavelengths using NIRC2 at Keck have resulted in a non-detection. Our new L'-band observations taken with the Large Binocular Telescope and L/M-band InfraRed Camera recover the companion (ΔL = 10.15 ± 0.15 mag, ρ = 0.''675 ± 0.''016) with a high signal-to-noise ratio (10σ). This measurement represents the deepest L' high-contrast imaging detection at subarcsecond separations to date, including extrasolar planets. We confirm that HD 114174 B has near-infrared colors consistent with the interpretation of a cool white dwarf (WD; J – L' = 0.76 ± 0.19 mag, K – L' = 0.64 ± 0.20). New model fits to the object's spectral energy distribution indicate a temperature T {sub eff} = 4260 ± 360 K, surface gravity log g = 7.94 ± 0.03, a cooling age t{sub c} ≈ 7.8 Gyr, and mass M = 0.54 ± 0.01 M {sub ☉}. We find that the cooling ages given by theoretical atmospheric models do not agree with the age of HD 114174 A derived from both isochronological and gyrochronological analyses. We speculate on possible scenarios to explain the apparent age discrepancy between the primary and secondary. HD 114174 B is a nearby benchmark WD that will ultimately enable a dynamical mass estimate through continued Doppler and astrometric monitoring. Efforts to characterize its physical properties in detail will test theoretical atmospheric models and improve our understanding of WD evolution, cooling, and progenitor masses.

On Shocks Driven by High-mass Planets in Radiatively Inefficient Disks. II. Three-dimensional Global Disk Simulations

Science.gov (United States)

Lyra, Wladimir; Richert, Alexander J. W.; Boley, Aaron; Turner, Neal; Mac Low, Mordecai-Mark; Okuzumi, Satoshi; Flock, Mario

2016-02-01

Recent high-resolution, near-infrared images of protoplanetary disks have shown that these disks often present spiral features. Spiral arms are among the structures predicted by models of disk-planet interaction and thus it is tempting to suspect that planetary perturbers are responsible for these signatures. However, such interpretation is not free of problems. The observed spirals have large pitch angles, and in at least one case (HD 100546) it appears effectively unpolarized, implying thermal emission of the order of 1000 K (465 ± 40 K at closer inspection). We have recently shown in two-dimensional models that shock dissipation in the supersonic wake of high-mass planets can lead to significant heating if the disk is sufficiently adiabatic. Here we extend this analysis to three dimensions in thermodynamically evolving disks. We use the Pencil Code in spherical coordinates for our models, with a prescription for thermal cooling based on the optical depth of the local vertical gas column. We use a 5MJ planet, and show that shocks in the region around the planet where the Lindblad resonances occur heat the gas to substantially higher temperatures than the ambient gas. The gas is accelerated vertically away from the midplane to form shock bores, and the gas falling back toward the midplane breaks up into a turbulent surf. This turbulence, although localized, has high α values, reaching 0.05 in the inner Lindblad resonance, and 0.1 in the outer one. We find evidence that the disk regions heated up by the shocks become superadiabatic, generating convection far from the planet’s orbit.

CHEMICAL IMAGING OF THE CO SNOW LINE IN THE HD 163296 DISK

Energy Technology Data Exchange (ETDEWEB)

Qi, Chunhua; Öberg, Karin I.; Andrews, Sean M.; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Hughes, A. Meredith [Van Vleck Observatory, Astronomy Department, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Hogherheijde, Michiel [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); D’Alessio, Paola [Centro de Radioastronomi´a y Astrofísica, Universidad Nacional Autónoma de México, 58089 Morelia, Michoacán, México (Mexico)

2015-11-10

The condensation fronts (snow lines) of H{sub 2}O, CO, and other abundant volatiles in the midplane of a protoplanetary disk affect several aspects of planet formation. Locating the CO snow line, where the CO gas column density is expected to drop substantially, based solely on CO emission profiles, is challenging. This has prompted an exploration of chemical signatures of CO freeze-out. We present ALMA Cycle 1 observations of the N{sub 2}H{sup +} J = 3−2 and DCO{sup +} J = 4−3 emission lines toward the disk around the Herbig Ae star HD 163296 at ∼0.″5 (60 AU) resolution, and evaluate their utility as tracers of the CO snow line location. The N{sub 2}H{sup +} emission is distributed in a ring with an inner radius at 90 AU, corresponding to a midplane temperature of 25 K. This result is consistent with a new analysis of optically thin C{sup 18}O data, which implies a sharp drop in CO abundance at 90 AU. Thus N{sub 2}H{sup +} appears to be a robust tracer of the midplane CO snow line. The DCO{sup +} emission also has a ring morphology, but neither the inner nor the outer radius coincide with the CO snow line location of 90 AU, indicative of a complex relationship between DCO{sup +} emission and CO freeze-out in the disk midplane. Compared to TW Hya, CO freezes out at a higher temperature in the disk around HD 163296 (25 versus 17 K in the TW Hya disk), perhaps due to different ice compositions. This highlights the importance of actually measuring the CO snow line location, rather than assuming a constant CO freeze-out temperature for all disks.

DYNAMICAL MASS OF THE SUBSTELLAR BENCHMARK BINARY HD 130948BC , ,

International Nuclear Information System (INIS)

Dupuy, Trent J.; Liu, Michael C.; Ireland, Michael J.

2009-01-01

We present Keck adaptive optics imaging of the L4+L4 binary HD 130948BC along with archival Hubble Space Telescope and Gemini North observations, which together span ∼ 70% of the binary's orbital period. From the relative orbit, we determine a total dynamical mass of 0.109 ± 0.003 M sun (114 ± 3 M Jup ). The flux ratio of HD 130948BC is near unity, so both components are unambiguously substellar for any plausible mass ratio. An independent constraint on the age of the system is available from the primary HD 130948A (G2V, [M/H] = 0.0). The ensemble of available indicators suggests an age comparable to Hyades, with the most precise age being 0.79 +0.22 -0.15 Gyr based on gyrochronology. Therefore, HD 130948BC is now a unique benchmark among field L and T dwarfs, with a well-determined mass, luminosity, and age. We find that substellar theoretical models disagree with our observations. (1) Both components of HD 130948BC appear to be overluminous by a factor of ∼ 2-3 times compared to evolutionary models. The age of the system would have to be notably younger than the gyro age to ameliorate the luminosity disagreement. (2) Effective temperatures derived from evolutionary models for HD 130948B and C are inconsistent with temperatures determined from spectral synthesis for objects of similar spectral type. Overall, regardless of the adopted age, evolutionary and atmospheric models give inconsistent results, which indicate systematic errors in at least one class of models, possibly both. The masses of HD 130948BC happen to be very near the theoretical mass limit for lithium burning, and thus measuring the differential lithium depletion between B and C will provide a uniquely discriminating test of theoretical models. The potential underestimate of luminosities by evolutionary models would have wide-ranging implications; therefore, a more refined estimate age for HD 130948A is critically needed.

The CARMENES search for exoplanets around M dwarfs. HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf

Science.gov (United States)

Reiners, A.; Ribas, I.; Zechmeister, M.; Caballero, J. A.; Trifonov, T.; Dreizler, S.; Morales, J. C.; Tal-Or, L.; Lafarga, M.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Jeffers, S. V.; Aceituno, J.; Béjar, V. J. S.; Guàrdia, J.; Guenther, E. W.; Hagen, H.-J.; Montes, D.; Passegger, V. M.; Seifert, W.; Schweitzer, A.; Cortés-Contreras, M.; Abril, M.; Alonso-Floriano, F. J.; Eiff, M. Ammler-von; Antona, R.; Anglada-Escudé, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Benítez, D.; Berdiñas, Z. M.; Bergond, G.; Blümcke, M.; Brinkmöller, M.; del Burgo, C.; Cano, J.; Cárdenas Vázquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colomé, J.; Czesla, S.; Díez-Alonso, E.; Feiz, C.; Fernández, M.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Gómez Galera, V.; González Hernández, J. I.; González-Peinado, R.; Grözinger, U.; Grohnert, S.; Guijarro, A.; de Guindos, E.; Gutiérrez-Soto, J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, Th.; Hermelo, I.; Hernández Arabí, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Kürster, M.; Labarga, F.; Lamert, A.; Lampón, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; López del Fresno, M.; López-González, M. J.; López-Puertas, M.; López Salas, J. F.; López-Santiago, J.; Luque, R.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Pascual, J.; Pavlov, A.; Pedraz, S.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H.-W.; Rodler, F.; Rodríguez, E.; Rodríguez-López, C.; Rodríguez Trinidad, A.; Rohloff, R.-R.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schöfer, P.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tala, M.; Tulloch, S. M.; Ulbrich, R.-G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R.

2018-02-01

We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V = 8.9 mag, M = 0.58 ± 0.08 M⊙), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of K = 5.1 ± 0.4 m s-1 and a period of P = 86.54 ± 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass mP sin i = 25 ± 2 M⊕, 1.5 times the mass of Neptune, with an orbital semi-major axis a = 0.32 au and low eccentricity (e ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/L5

H/D isotope effects in high temperature proton conductors

DEFF Research Database (Denmark)

Bonanos, Nikolaos; Huijser, A.; Poulsen, Finn Willy

2015-01-01

The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D...

Magic Planet

DEFF Research Database (Denmark)

Jacobsen, Aase Roland

2009-01-01

Med den digitale globe som omdrejningspunkt bestemmer publikum, hvilken planet, der er i fokus. Vores solsystem udforskes interaktivt. Udgivelsesdato: november......Med den digitale globe som omdrejningspunkt bestemmer publikum, hvilken planet, der er i fokus. Vores solsystem udforskes interaktivt. Udgivelsesdato: november...

Dance of the Planets

Science.gov (United States)

Riddle, Bob

2005-01-01

As students continue their monthly plotting of the planets along the ecliptic they should start to notice differences between inner and outer planet orbital motions, and their relative position or separation from the Sun. Both inner and outer planets have direct eastward motion, as well as retrograde motion. Inner planets Mercury and Venus,…

Exploring Disks Around Planets

Science.gov (United States)

Kohler, Susanna

2017-07-01

Giant planets are thought to form in circumstellar disks surrounding young stars, but material may also accrete into a smaller disk around the planet. Weve never detected one of these circumplanetary disks before but thanks to new simulations, we now have a better idea of what to look for.Image from previous work simulating a Jupiter-mass planet forming inside a circumstellar disk. The planet has its own circumplanetary disk of accreted material. [Frdric Masset]Elusive DisksIn the formation of giant planets, we think the final phase consists of accretion onto the planet from a disk that surrounds it. This circumplanetary disk is important to understand, since it both regulates the late gas accretion and forms the birthplace of future satellites of the planet.Weve yet to detect a circumplanetary disk thus far, because the resolution needed to spot one has been out of reach. Now, however, were entering an era where the disk and its kinematics may be observable with high-powered telescopes (like the Atacama Large Millimeter Array).To prepare for such observations, we need models that predict the basic characteristics of these disks like the mass, temperature, and kinematic properties. Now a researcher at the ETH Zrich Institute for Astronomy in Switzerland, Judit Szulgyi, has worked toward this goal.Simulating CoolingSzulgyi performs a series of 3D global radiative hydrodynamic simulations of 1, 3, 5, and 10 Jupiter-mass (MJ) giant planets and their surrounding circumplanetary disks, embedded within the larger circumstellar disk around the central star.Density (left column), temperature (center), and normalized angular momentum (right) for a 1 MJ planet over temperatures cooling from 10,000 K (top) to 1,000 K (bottom). At high temperatures, a spherical circumplanetary envelope surrounds the planet, but as the planet cools, the envelope transitions around 64,000 K to a flattened disk. [Szulgyi 2017]This work explores the effects of different planet temperatures and

Planets a very short introduction

CERN Document Server

Rothery, David A

2010-01-01

Planets: A Very Short Introduction demonstrates the excitement, uncertainties, and challenges faced by planetary scientists, and provides an overview of our Solar System and its origins, nature, and evolution. Terrestrial planets, giant planets, dwarf planets and various other objects such as satellites (moons), asteroids, trans-Neptunian objects, and exoplanets are discussed. Our knowledge about planets has advanced over the centuries, and has expanded at a rapidly growing rate in recent years. Controversial issues are outlined, such as What qualifies as a planet? What conditions are required for a planetary body to be potentially inhabited by life? Why does Pluto no longer have planet status? And Is there life on other planets?

Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

Science.gov (United States)

Jensen-Clem, Rebecca; Millar-Blanchaer, Max; Mawet, Dimitri; Graham, James R.; Wallace, J. Kent; Macintosh, Bruce; Hinkley, Sasha; Wiktorowicz, Sloane J.; Perrin, Marshall D.; Marley, Mark S.;

The Trojan minor planets

Science.gov (United States)

Spratt, Christopher E.

1988-08-01

There are (March, 1988) 3774 minor planets which have received a permanent number. Of these, there are some whose mean distance to the sun is very nearly equal to that of Jupiter, and whose heliocentric longitudes from that planet are about 60°, so that the three bodies concerned (sun, Jupiter, minor planet) make an approximate equilateral triangle. These minor planets, which occur in two distinct groups, one preceding Jupiter and one following, have received the names of the heroes of the Trojan war. This paper concerns the 49 numbered minor planets of this group.

Inside-out Planet Formation. IV. Pebble Evolution and Planet Formation Timescales

Science.gov (United States)

Hu, Xiao; Tan, Jonathan C.; Zhu, Zhaohuan; Chatterjee, Sourav; Birnstiel, Tilman; Youdin, Andrew N.; Mohanty, Subhanjoy

2018-04-01

Systems with tightly packed inner planets (STIPs) are very common. Chatterjee & Tan proposed Inside-out Planet Formation (IOPF), an in situ formation theory, to explain these planets. IOPF involves sequential planet formation from pebble-rich rings that are fed from the outer disk and trapped at the pressure maximum associated with the dead zone inner boundary (DZIB). Planet masses are set by their ability to open a gap and cause the DZIB to retreat outwards. We present models for the disk density and temperature structures that are relevant to the conditions of IOPF. For a wide range of DZIB conditions, we evaluate the gap-opening masses of planets in these disks that are expected to lead to the truncation of pebble accretion onto the forming planet. We then consider the evolution of dust and pebbles in the disk, estimating that pebbles typically grow to sizes of a few centimeters during their radial drift from several tens of astronomical units to the inner, ≲1 au scale disk. A large fraction of the accretion flux of solids is expected to be in such pebbles. This allows us to estimate the timescales for individual planet formation and the entire planetary system formation in the IOPF scenario. We find that to produce realistic STIPs within reasonable timescales similar to disk lifetimes requires disk accretion rates of ∼10‑9 M ⊙ yr‑1 and relatively low viscosity conditions in the DZIB region, i.e., a Shakura–Sunyaev parameter of α ∼ 10‑4.

Cytogenetic studies in dogs after total body irradiation and allogeneic transfusion with cryopreserved blood mononuclear cells: observations in long-term chimeras

International Nuclear Information System (INIS)

Carbonell, F.; Calvo, W.; Fliedner, T.M.; Kratt, E.; Gerhartz, H.; Koerbling, M.; Nothdurft, W.; Ross, W.M.

1984-01-01

Cytogenetic studies were performed on two dog groups after total body irradiation and allogeneic transfusion with cryopreserved blood mononuclear cells. The first group of dogs was transfused with unseparated leukocytes and suffered from graft-versus-host disease (GvHD). Cytogenetic studies demonstrated only cells of donor origin in all dogs of this group. The second group of animals was transfused with fraction 2 of a discontinuous albumin gradient. The dogs of this group did not develop GvHD, and the cytogenetic studies showed the presence of a mosaic of cells from donor and recipient origin in all of them. These results suggest that the GvHD may suppress autochthonous regeneration

Exoplanets: The Hunt Continues!

Science.gov (United States)

2001-04-01

Swiss Telescope at La Silla Very Successful Summary The intensive and exciting hunt for planets around other stars ( "exoplanets" ) is continuing with great success in both hemispheres. Today, an international team of astronomers from the Geneva Observatory and other research institutes [1] is announcing the discovery of no less than eleven new, planetary companions to solar-type stars, HD 8574, HD 28185, HD 50554, HD 74156, HD 80606, HD 82943, HD 106252, HD 141937, HD 178911B, HD 141937, among which two new multi-planet systems . The masses of these new objects range from slightly less than to about 10 times the mass of the planet Jupiter [2]. The new detections are based on measured velocity changes of the stars [3], performed with the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory , as well as with instruments on telescopes at the Haute-Provence Observatory and on the Keck telescopes on Mauna Kea (Hawaii, USA). Some of the new planets are unusual: * a two-planet system (around the star HD 82943) in which one orbital period is nearly exactly twice as long as the other - cases like this (refered to as "orbital resonance") are well known in our own solar system; * another two-planet system (HD 74156), with a Jupiter-like planet and a more massive planet further out; * a planet with the most elongated orbit detected so far (HD 80606), moving between 5 and 127 million kilometers from the central star; * a giant planet moving in an orbit around its Sun-like central star that is very similar to the one of the Earth and whose potential satellites (in theory, at least) might be "habitable". At this moment, there are 63 know exoplanet candidates with minimum masses below 10 Jupiter masses, and 67 known objects with minimum masses below 17 Jupiter masses. The present team of astronomers has detected about half of these. PR Photo 13a/01 : Radial-velocity measurements of HD 82943, a two-planet system . PR Photo 13b/01 : Radial

Comorbid externalising behaviour in AD/HD: evidence for a distinct pathological entity in adolescence.

Directory of Open Access Journals (Sweden)

Sharnel Perera

Full Text Available While the profiling of subtypes of Attention Deficit Hyperactivity Disorder (AD/HD have been the subject of considerable scrutiny, both psychometrically and psychophysiologically, little attention has been paid to the effect of diagnoses comorbid with AD/HD on such profiles. This is despite the greater than 80% prevalence of comorbidity under the DSM-IV-TR diagnostic definitions. Here we investigate the event related potential (ERP and psychometric profiles of Controls, AD/HD, and comorbid AD/HD (particularly AD/HD+ODD/CD groups on six neurocognitive tasks thought to probe the constructs of selective and sustained attention, response inhibition and executive function. Data from 29 parameters extracted from a child group (age range 6 to 12; 52 Controls and 64 AD/HD and from an adolescent group (age range 13 to 17; 79 Controls and 88 AD/HD were reduced via a Principal Components Analysis, the 6 significant eigenvectors then used as determinants of cluster membership via a Two-Step Cluster Analysis. Two clusters were found in the analysis of the adolescent age group--a cluster dominated by Control and AD/HD participants without comorbidity, while the second cluster was dominated by AD/HD participants with externalising comorbidity (largely oppositional defiant/conduct disorder ODD/CD. A similar segregation within the child age group was not found. Further analysis of these objectively determined clusters in terms of their clinical diagnoses indicates a significant effect of ODD/CD comorbidity on a concurrent AD/HD diagnosis. We conclude that comorbid externalising behaviour in AD/HD constitutes a distinct pathological entity in adolescence.

GEMINI PLANET IMAGER SPECTROSCOPY OF THE HR 8799 PLANETS c AND d

International Nuclear Information System (INIS)

Ingraham, Patrick; Macintosh, Bruce; Marley, Mark S.; Saumon, Didier; Marois, Christian; Dunn, Jennifer; Erikson, Darren; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey K.; Fitzgerald, Michael P.; De Rosa, Robert J.; Dillon, Daren; Gavel, Donald; Doyon, René; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Graham, James R.

2014-01-01

During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets' spectral energy distributions. When combined with the 3 to 4 μm photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. The data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity

Inside-out planet formation

International Nuclear Information System (INIS)

Chatterjee, Sourav; Tan, Jonathan C.

2014-01-01

The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ≳ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (∼cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ∼1 M ⊕ planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Johnson, B. C.; Melosh, H. J. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Thebault, P. [LESIA, Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Henning, W. G. [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Gaidos, E. [Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Elkins-Tanton, L. T. [Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States); Bridges, J. C. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Morlok, A., E-mail: johns477@purdue.edu [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

2012-12-10

Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10{sup 19} kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at {approx}6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that {approx}10{sup 47} molecules of SiO vapor are needed to explain an emission feature at {approx}8 {mu}m in the Spitzer IRS spectrum of HD 172555. We find that unless there are {approx}10{sup 48} atoms or 0.05 M{sub Circled-Plus} of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the {approx}8 {mu}m feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

TEN NEW AND UPDATED MULTIPLANET SYSTEMS AND A SURVEY OF EXOPLANETARY SYSTEMS

International Nuclear Information System (INIS)

Wright, J. T.; Upadhyay, S.; Marcy, G. W.; Fischer, D. A.; Ford, Eric B.; Johnson, John Asher

2009-01-01

We present the latest velocities for ten multiplanet systems, including a re-analysis of archival Keck and Lick data, resulting in improved velocities that supersede our previously published measurements. We derive updated orbital fits for 10 Lick and Keck systems, including two systems (HD 11964, HD 183263) for which we provide confirmation of second planets only tentatively identified elsewhere, and two others (HD 187123 and HD 217107) for which we provide a major revision of the outer planet's orbit. We compile orbital elements from the literature to generate a catalog of the 28 published multiple-planet systems around stars within 200 pc. From this catalog we find several intriguing patterns emerging: (1) including those systems with long-term radial velocity trends, at least 28% of known planetary systems appear to contain multiple planets; (2) planets in multiple-planet systems have somewhat smaller eccentricities than single planets; and (3) the distribution of orbital distances of planets in multiplanet systems and single planets are inconsistent: single-planet systems show a pileup at P ∼ 3 days and a jump near 1 AU, while multiplanet systems show a more uniform distribution in log-period. In addition, among all planetary systems we find the following. (1) There may be an emerging, positive correlation between stellar mass and giant-planet semimajor axis. (2) Exoplanets with M sin i > 1 M Jup more massive than Jupiter have eccentricities broadly distributed across 0 < e < 0.5, while lower mass exoplanets exhibit a distribution peaked near e = 0.

Formation of S-type planets in close binaries: scattering induced tidal capture of circumbinary planets

Science.gov (United States)

Gong, Yan-Xiang; Ji, Jianghui

2018-05-01

Although several S-type and P-type planets in binary systems were discovered in past years, S-type planets have not yet been found in close binaries with an orbital separation not more than 5 au. Recent studies suggest that S-type planets in close binaries may be detected through high-accuracy observations. However, nowadays planet formation theories imply that it is difficult for S-type planets in close binaries systems to form in situ. In this work, we extensively perform numerical simulations to explore scenarios of planet-planet scattering among circumbinary planets and subsequent tidal capture in various binary configurations, to examine whether the mechanism can play a part in producing such kind of planets. Our results show that this mechanism is robust. The maximum capture probability is ˜10%, which can be comparable to the tidal capture probability of hot Jupiters in single star systems. The capture probability is related to binary configurations, where a smaller eccentricity or a low mass ratio of the binary will lead to a larger probability of capture, and vice versa. Furthermore, we find that S-type planets with retrograde orbits can be naturally produced via capture process. These planets on retrograde orbits can help us distinguish in situ formation and post-capture origin for S-type planet in close binaries systems. The forthcoming missions (PLATO) will provide the opportunity and feasibility to detect such planets. Our work provides several suggestions for selecting target binaries in search for S-type planets in the near future.

Cutaneous Uptake of 14C-HD Vapor by the Hairless Guinea Pig.

Science.gov (United States)

1996-10-01

guinea pig (HGP) is used by our laboratory to model the human cutaneous response to sulfur mustard (HD) exposure. We have determined the HD content in the skin of HOP after 7-minute exposures to vapors saturated with a mixture of HD and 14C-HD. Concentration/time (C1) values in the range of 2 mg/sq cm/min were determined by counting skin 14C disintegrations per minute (dpm) in animals euthanized immediately after exposure. These values are similar to human penetration rates obtained by other investigators. A direct relationship between C1 and relative humidity was

TERRESTRIAL PLANET FORMATION DURING THE MIGRATION AND RESONANCE CROSSINGS OF THE GIANT PLANETS

International Nuclear Information System (INIS)

Lykawka, Patryk Sofia; Ito, Takashi

2013-01-01

The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ∼ 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths)

HD-DVD: the next consumer electronics revolution?

Science.gov (United States)

Topiwala, Pankaj N.

2003-11-01

The DVD is emerging as one of the world's favorite consumer electronics product, rapidly replacing analog videotape in the US and many other markets at prodigious rates. It is capable of offering a full feature-length, standard-definition movie in crisp rendition on TV. TV technology is itself in the midst of switching from analog to digital TV, with high-definition being the main draw. In fact, the US government has been advocating that switch over to digital TC, with both carrot and stick approaches, for nearly two decades, with only modest results--about 2% penetration. Under FCC herding, broadcasters are falling in the digital line--slowly, and sans profit. Meanwhile, delivery of HD content on portable media would be a great solution. Indeed, a new disk technology based on blue lasers is coming; but its widespread adoption may yet be four to five yeras away. But a promising new video codec--H.264/MPEG-4 AVC, the latest coding standard jointly developed by the Video Coding Experts Group (VCEG) of ITU-T and Moving Picture Experts Group (MPEG) of ISO/IEC, just might be the missing link. It offers substantial coding gains over MPEG-2, used in today's DVDs. With H.264, it appears possible to put HD movies on today's red-laser DVDs. Since consumers love DVDs, and HD--when they can see it, can H.264 and HD-DVD ignite a new revolution, now? It may have a huge impact on (H)DTV adoption rates.

ON SHOCKS DRIVEN BY HIGH-MASS PLANETS IN RADIATIVELY INEFFICIENT DISKS. II. THREE-DIMENSIONAL GLOBAL DISK SIMULATIONS

International Nuclear Information System (INIS)

Lyra, Wladimir; Richert, Alexander J. W.; Boley, Aaron; Turner, Neal; Okuzumi, Satoshi; Flock, Mario; Mac Low, Mordecai-Mark

2016-01-01

Recent high-resolution, near-infrared images of protoplanetary disks have shown that these disks often present spiral features. Spiral arms are among the structures predicted by models of disk–planet interaction and thus it is tempting to suspect that planetary perturbers are responsible for these signatures. However, such interpretation is not free of problems. The observed spirals have large pitch angles, and in at least one case (HD 100546) it appears effectively unpolarized, implying thermal emission of the order of 1000 K (465 ± 40 K at closer inspection). We have recently shown in two-dimensional models that shock dissipation in the supersonic wake of high-mass planets can lead to significant heating if the disk is sufficiently adiabatic. Here we extend this analysis to three dimensions in thermodynamically evolving disks. We use the Pencil Code in spherical coordinates for our models, with a prescription for thermal cooling based on the optical depth of the local vertical gas column. We use a 5M J planet, and show that shocks in the region around the planet where the Lindblad resonances occur heat the gas to substantially higher temperatures than the ambient gas. The gas is accelerated vertically away from the midplane to form shock bores, and the gas falling back toward the midplane breaks up into a turbulent surf. This turbulence, although localized, has high α values, reaching 0.05 in the inner Lindblad resonance, and 0.1 in the outer one. We find evidence that the disk regions heated up by the shocks become superadiabatic, generating convection far from the planet’s orbit

Ultraviolet irradiation modulates MHC-alloreactive cytotoxic T-cell precursors involved in the onset of graft-versus-host disease

International Nuclear Information System (INIS)

Prooijen, H.C. Van; Aarts-Riemens, M.I.; Weelden, H. Van; Grijzenhout, M.A.

1992-01-01

Ultraviolet B (UVB) irradiation of cellular blood components has been proposed as a new technology to prevent HLA sensitization in recipients. Earlier studies have shown that a dose of 2 J/cm 2 abrogates the ability of lymphocytes to serve as stimulators in mixed lymphocyte cultures (MLC). In this study the authors evaluate the effect of UV energy on T-lymphocytes for the prevention of transfusion-associated graft-versus-host disease (TA-GvHD). The response of cytotoxic T-lymphocyte precursors against host alloantigens was almost undetectable at a dose of 0.5 J/cm 2 . T-cell proliferation in MLC or in response to phytohaemagglutinin was inhibited by more than 95% at doses of 1 J/cm 2 or higher. The data suggest that UV irradiation can be used to prevent both HLA sensitization and TA-GvHD in recipients. (Author)

In vitro experiments for the development of a high density (HD) barium sulfate contrast medium

International Nuclear Information System (INIS)

Klein, J.

1986-01-01

In vitro experiments with the high-density (HD) barium meal Falibaryt HD are described. Several charges of BaSO 4 were tested together with certain additives influencing dispersion, stability of the suspension, flowability, surface tension etc. Particle size spectra were measured by the manufacturer, VEB Fahlberg-List. With a simple PVC test plate containing several grooves simulating small details (areae gastricae) the diagnostic capabilities of the HD contrast medium were evaluated in an in vitro test. The developed barium meal Falibaryt HD is in its physical and chemical parameters comparable with Prontobario-HD, one of the best HD barium meals. (author)

Taxonomy of the extrasolar planet.

Science.gov (United States)

Plávalová, Eva

2012-04-01

When a star is described as a spectral class G2V, we know that the star is similar to our Sun. We know its approximate mass, temperature, age, and size. When working with an extrasolar planet database, it is very useful to have a taxonomy scale (classification) such as, for example, the Harvard classification for stars. The taxonomy has to be easily interpreted and present the most relevant information about extrasolar planets. I propose an extrasolar planet taxonomy scale with four parameters. The first parameter concerns the mass of an extrasolar planet in the form of units of the mass of other known planets, where M represents the mass of Mercury, E that of Earth, N Neptune, and J Jupiter. The second parameter is the planet's distance from its parent star (semimajor axis) described in a logarithm with base 10. The third parameter is the mean Dyson temperature of the extrasolar planet, for which I established four main temperature classes: F represents the Freezing class, W the Water class, G the Gaseous class, and R the Roasters class. I devised one additional class, however: P, the Pulsar class, which concerns extrasolar planets orbiting pulsar stars. The fourth parameter is eccentricity. If the attributes of the surface of the extrasolar planet are known, we are able to establish this additional parameter where t represents a terrestrial planet, g a gaseous planet, and i an ice planet. According to this taxonomy scale, for example, Earth is 1E0W0t, Neptune is 1N1.5F0i, and extrasolar planet 55 Cnc e is 9E-1.8R1.

Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B)(exp 1): Implications for the Physical State of the Disk from Spiral Density Wave Theory

Science.gov (United States)

Muto, T.; Grady, C. A.; Hashimoto, J.; Fukagawa, M.; Hornbeck, J. B.; Sitko, M.; Russell, R.; Werren, C.; Cure, M; Currie, T.;

HD271791: dynamical versus binary-supernova ejection scenario

OpenAIRE

Gvaramadze, V. V.

2009-01-01

The atmosphere of the extremely high-velocity (530-920 km/s) early B-type star HD271791 is enriched in $\\alpha$-process elements, which suggests that this star is a former secondary component of a massive tight binary system and that its surface was polluted by the nucleosynthetic products after the primary star exploded in a supernova. It was proposed that the (asymmetric) supernova explosion unbind the system and that the secondary star (HD271791) was released at its orbital velocity in the...

CHEMICAL CONSEQUENCES OF THE C/O RATIO ON HOT JUPITERS: EXAMPLES FROM WASP-12b, CoRoT-2b, XO-1b, AND HD 189733b

Energy Technology Data Exchange (ETDEWEB)

Moses, J. I. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Madhusudhan, N. [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Visscher, C. [Southwest Research Institute, Boulder, CO 80302 (United States); Freedman, R. S., E-mail: jmoses@spacescience.org [SETI Institute, Mountain View, CA 94043 (United States)

2013-01-20

Motivated by recent spectroscopic evidence for carbon-rich atmospheres on some transiting exoplanets, we investigate the influence of the C/O ratio on the chemistry, composition, and spectra of extrasolar giant planets both from a thermochemical equilibrium perspective and from consideration of disequilibrium processes like photochemistry and transport-induced quenching. We find that although CO is predicted to be a major atmospheric constituent on hot Jupiters for all C/O ratios, other oxygen-bearing molecules like H{sub 2}O and CO{sub 2} are much more abundant when C/O < 1, whereas CH{sub 4}, HCN, and C{sub 2}H{sub 2} gain significantly in abundance when C/O > 1. Other notable species like N{sub 2} and NH{sub 3} that do not contain carbon or oxygen are relatively unaffected by the C/O ratio. Disequilibrium processes tend to enhance the abundance of CH{sub 4}, NH{sub 3}, HCN, and C{sub 2}H{sub 2} over a wide range of C/O ratios. We compare the results of our models with secondary-eclipse photometric data from the Spitzer Space Telescope and conclude that (1) disequilibrium models with C/O {approx} 1 are consistent with spectra of WASP-12b, XO-1b, and CoRoT-2b, confirming the possible carbon-rich nature of these planets; (2) spectra from HD 189733b are consistent with C/O {approx}< 1, but as the assumed metallicity is increased above solar, the required C/O ratio must increase toward 1 to prevent too much H{sub 2}O absorption; (3) species like HCN can have a significant influence on spectral behavior in the 3.6 and 8.0 {mu}m Spitzer channels, potentially providing even more opacity than CH{sub 4} when C/O > 1; and (4) the very high CO{sub 2} abundance inferred for HD 189733b from near-infrared observations cannot be explained through equilibrium or disequilibrium chemistry in a hydrogen-dominated atmosphere. We discuss possible formation mechanisms for carbon-rich hot Jupiters, including scenarios in which the accretion of CO-rich, H{sub 2}O-poor gas dominates the

Observed properties of extrasolar planets.

Science.gov (United States)

Howard, Andrew W

2013-05-03

Observational surveys for extrasolar planets probe the diverse outcomes of planet formation and evolution. These surveys measure the frequency of planets with different masses, sizes, orbital characteristics, and host star properties. Small planets between the sizes of Earth and Neptune substantially outnumber Jupiter-sized planets. The survey measurements support the core accretion model, in which planets form by the accumulation of solids and then gas in protoplanetary disks. The diversity of exoplanetary characteristics demonstrates that most of the gross features of the solar system are one outcome in a continuum of possibilities. The most common class of planetary system detectable today consists of one or more planets approximately one to three times Earth's size orbiting within a fraction of the Earth-Sun distance.

Histories of terrestrial planets

International Nuclear Information System (INIS)

Benes, K.

1981-01-01

The uneven historical development of terrestrial planets - Mercury, Venus, Earth, Moon and Mars - is probably due to the differences in their size, weight and rotational dynamics in association with the internal planet structure, their distance from the Sun, etc. A systematic study of extraterrestrial planets showed that the time span of internal activity was not the same for all bodies. It is assumed that the initial history of all terrestrial planets was marked with catastrophic events connected with the overall dynamic development of the solar system. In view of the fact that the cores of small terrestrial bodies cooled quicker, their geological development almost stagnated after two or three thousand million years. This is what probably happened to the Mercury and the Moon as well as the Mars. Therefore, traces of previous catastrophic events were preserved on the surface of the planets. On the other hand, the Earth is the most metamorphosed terrestrial planet and compared to the other planets appears to be atypical. Its biosphere is significantly developed as well as the other shell components, its hydrosphere and atmosphere, and its crust is considerably differentiated. (J.P.)

SECULAR BEHAVIOR OF EXOPLANETS: SELF-CONSISTENCY AND COMPARISONS WITH THE PLANET-PLANET SCATTERING HYPOTHESIS

Energy Technology Data Exchange (ETDEWEB)

Timpe, Miles; Barnes, Rory [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States); Kopparapu, Ravikumar; Raymond, Sean N. [Virtual Planetary Laboratory, Seattle, WA 98195 (United States); Greenberg, Richard [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Gorelick, Noel, E-mail: apskier@astro.washington.edu [Google, Inc., 1600 Amphitheater Parkway, Mountain View, CA 94043 (United States)

2013-09-15

If mutual gravitational scattering among exoplanets occurs, then it may produce unique orbital properties. For example, two-planet systems that lie near the boundary between circulation and libration of their periapses could result if planet-planet scattering ejected a former third planet quickly, leaving one planet on an eccentric orbit and the other on a circular orbit. We first improve upon previous work that examined the apsidal behavior of known multiplanet systems by doubling the sample size and including observational uncertainties. This analysis recovers previous results that demonstrated that many systems lay on the apsidal boundary between libration and circulation. We then performed over 12,000 three-dimensional N-body simulations of hypothetical three-body systems that are unstable, but stabilize to two-body systems after an ejection. Using these synthetic two-planet systems, we test the planet-planet scattering hypothesis by comparing their apsidal behavior, over a range of viewing angles, to that of the observed systems and find that they are statistically consistent regardless of the multiplicity of the observed systems. Finally, we combine our results with previous studies to show that, from the sampled cases, the most likely planetary mass function prior to planet-planet scattering follows a power law with index -1.1. We find that this pre-scattering mass function predicts a mutual inclination frequency distribution that follows an exponential function with an index between -0.06 and -0.1.

Elemental abundances of the field horizontal-branch stars HD 86986, 130095 and 202759

International Nuclear Information System (INIS)

Adelman, S.J.

1990-01-01

Fine analyses of limited spectral regions of the field horizontal-branch A Stars HD86986, 130095 and 202759 confirm that these stars have abundances typical of Population II stars. HD 86986 has a metallicity of about 1/200 solar while HD 130095 and 202759 are even more metal poor. (author)

Introduction and feasibility study of the HD-270 MLC

International Nuclear Information System (INIS)

Kim, Dae Young; Kim Won Taek; Lee, Hwa Jung; Lee, Kang Hyeok

2003-01-01

The multileaf collimator(MLC) has many advantages, but use of the MLC increased effective penumbra and isodose undulation in dose distribution compared with that of an alloy block. In this work, we introduced the HD-270 MLC, which can improve the above disadvantages of MLC, and reported its feasibility study. The HD-270 MLC is a technique which combines the use of the existing Siemens multileaf collimator(3D MLC) with patient translation perpendicular to the leaf plane. The technique produces a smoothed isodose distribution with the reduced isodose undulation and effective penumbra. To assess the efficacy of the HD-270 technique and determine the appropriate resolution, a polygonal shaped MLC field was made to produce field edge angles from 0 degree to 75 degree with a step of 15 degree. Each HD-270 group was generated according to the allowed resolution, i. e., 5, 3, and 2 mm. The experiment was carried out on Primus, a Siemens linear accelerator configured with HD-270 MLC. The total 60 MU of 6 MV photon beam was delivered to X-Omat film (Kodak, USA) at a SAD of 100 cm and 1.5 cm depth in solid water phantom. Exposed films were scanned by Lumiscan75(LUMISYS) and analyzed using RIT113 software (Radiological Imaging Technology Inc., USA). To test the mechanical accuracy of table movement, the transverse, longitudinal, and vertical positions were controlled by a consol with ±5 mm, ±4 mm, ±3 mm, and ±2 mm steps, and then measured using a dial gauge with an accuracy of 0.001 inch. During the experiments, the table loaded with about 50 Kg human phantom to simulate the real treatment situation. The effective penumbra and isodose undulation became larger with increase the resolution and field edge angle. The accuracy of the table movement on each direction is good within the ±1 mm. Clinical use of the MLC can be increased by using of the HD-270 MLC which complements to the disadvantages of the MLC.

Planets in Binary Star Systems

CERN Document Server

Haghighipour, Nader

2010-01-01

The discovery of extrasolar planets over the past decade has had major impacts on our understanding of the formation and dynamical evolution of planetary systems. There are features and characteristics unseen in our solar system and unexplainable by the current theories of planet formation and dynamics. Among these new surprises is the discovery of planets in binary and multiple-star systems. The discovery of such "binary-planetary" systems has confronted astrodynamicists with many new challenges, and has led them to re-examine the theories of planet formation and dynamics. Among these challenges are: How are planets formed in binary star systems? What would be the notion of habitability in such systems? Under what conditions can binary star systems have habitable planets? How will volatiles necessary for life appear on such planets? This volume seeks to gather the current research in the area of planets in binary and multistar systems and to familiarize readers with its associated theoretical and observation...

Habitable zone limits for dry planets.

Science.gov (United States)

Abe, Yutaka; Abe-Ouchi, Ayako; Sleep, Norman H; Zahnle, Kevin J

2011-06-01

Most discussion of habitable planets has focused on Earth-like planets with globally abundant liquid water. For an "aqua planet" like Earth, the surface freezes if far from its sun, and the water vapor greenhouse effect runs away if too close. Here we show that "land planets" (desert worlds with limited surface water) have wider habitable zones than aqua planets. For planets at the inner edge of the habitable zone, a land planet has two advantages over an aqua planet: (i) the tropics can emit longwave radiation at rates above the traditional runaway limit because the air is unsaturated and (ii) the dry air creates a dry stratosphere that limits hydrogen escape. At the outer limits of the habitable zone, the land planet better resists global freezing because there is less water for clouds, snow, and ice. Here we describe a series of numerical experiments using a simple three-dimensional global climate model for Earth-sized planets. Other things (CO(2), rotation rate, surface pressure) unchanged, we found that liquid water remains stable at the poles of a low-obliquity land planet until net insolation exceeds 415 W/m(2) (170% that of modern Earth), compared to 330 W/m(2) (135%) for the aqua planet. At the outer limits, we found that a low-obliquity land planet freezes at 77%, while the aqua planet freezes at 90%. High-obliquity land and aqua planets freeze at 58% and 72%, respectively, with the poles offering the last refuge. We show that it is possible that, as the Sun brightens, an aqua planet like Earth can lose most of its hydrogen and become a land planet without first passing through a sterilizing runaway greenhouse. It is possible that Venus was a habitable land planet as recently as 1 billion years ago.

Effects of gamma-irradiation of plastics on migration of constituents into test foods

International Nuclear Information System (INIS)

Figge, K.; Freytag, W.

1977-01-01

Test films prepared from polyethylene (LD- and HD-PE), polypropylene (PP), polystyrene (St- and HI-PS) and polyvinylchloride (rigid PVC) compositions under addition of 2,6-di-tert-butyl-4-methyl[ 14 C]-phenol(I), 3-(3,5-di-tert-butyl -4-hydroxyphenyl)- stearyl-propionate[3- 14 C] (II), n-butyl-stearate[1- 14 C] (III) di-n-octyl[1- 14 C]-tin-2 -ethyl-hexyl-di-thioglycolate inclusive of the corresponding mono-n-octyl[1- 14 C]-tin compound (IV-Oc), di-n-octyl-tin-2-ethylhexyl -di-thioglycolate[2- 14 C] inclusive of the corresponding 2-ethylhexyl-tri -thioglycolate[2- 14 C] (IV-S) or of stearyl alcohol [1- 14 C] (V) respectively, were sterilized in a 60 Co irradiation unit with a radiation dosage of 2,5 Mrad. Then, the irradiated films as well as non-treated reference films were kept in one-sided contact with the test foodstuffs 'dist. Water' and HB 307 (test fat) for 10 days at 40 0 C. Under these conditions the additives I and II migrated from the PP, HD-PE and LD-PE test films into the test fat HB 307 in amounts of 10 to 50%. Migration into distilled water was only 0.05 to 4.6%. The migration of the additives I and II from the irradiated polyolefin test films into the test fat HB 307 was by 8 to 38% lower than that from the corresponding non-irradiated films. In contrast to this, both additives migrated distinctly more strongly from the irradiated polyolefin test films into distilled water, i.e. 1.9 to 8.7 times stronger than from the non-irradiated films. The migration of the additives I to V from the HI-PS St-PS and rigid PVC test films into the two test foodstuffs was very low, in most cases below 0.1%. Generally lower amounts of additive migrated from the irradiated films than from the non-irradiated samples. (orig.) [de

The impact of reinforcement contingencies on AD/HD: a review and theoretical appraisal.

Science.gov (United States)

Luman, Marjolein; Oosterlaan, Jaap; Sergeant, Joseph A

2005-02-01

One of the core deficits in attention deficit/hyperactivity disorder (AD/HD) is thought to be an aberrant sensitivity to reinforcement, such as reward and response cost. Twenty-two studies (N=1181 children) employing AD/HD and reinforcement contingencies are reviewed from vantage points: task performance, motivation, and psychophysiology. Results indicate that reinforcement contingencies have a positive impact on task performance and levels of motivation for both children with AD/HD and normal controls. There is evidence that the effect related to task performance is somewhat more prominent in AD/HD. There is some evidence that a high intensity of reinforcement is highly effective in AD/HD. Children with AD/HD prefer immediate over delayed reward. From a psychophysiological point of view, children with AD/HD seem less sensitive to reinforcement compared to controls. While comorbid disorders are suggested to be confounders of the dependent variables, many studies do not examine the effect of oppositional defiant disorder (ODD) and conduct disorder (CD). We discuss the implications of the findings for five theoretical frameworks, including the model by, the cognitive-energetic model (CEM), the dual-pathway model and the BIS/BAS model. Results show a discrepancy between the theoretical models and the behavioural findings.

Light variations of the population II F-type supergiant HD 46703

Science.gov (United States)

Bond, H. E.; Carney, B. W.; Grauer, A. D.

1984-01-01

Photometric monitoring has revealed brightness variations of 0.1 m on a time scale of weeks for HD 46703, a metal-deficient F-type field analog of the stars lying above the horizontal branch in globular clusters. It is suggested that HD 46703 belongs to the '89 Her' class of luminous F-type variables. Since HD 46703 is unquestionably a halo object, it is almost certainly a low-mass star. It is suggested that it, and probably the other 89 Her variables, are masquerading as supergiants during their final evolution off the asymptotic giant branch.

Discovery of a Probable 4-5 Jupiter-mass Exoplanet to HD 95086 by Direct Imaging

Science.gov (United States)

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Boccaletti, A.; Quanz, S. P.; Bonnefoy, M.; Girard, J. H.; Delorme, P.; Desidera, S.; Klahr, H.; Mordasini, C.; Dumas, C.; Bonavita, M.

2013-08-01

Direct imaging has only begun to inventory the population of gas giant planets on wide orbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. Here we report the discovery of a probable companion orbiting the young (10-17 Myr), dusty, early-type (A8) star HD 95086 at 56 AU in L' (3.8 μm) images. This discovery is based on observations with more than a year time lapse. Our first epoch clearly revealed the source at ~= 10σ, while our second epoch lacks good observing conditions, yielding a ~= 3σ detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests that the companion is comoving with the star with a 3σ confidence level. The planetary nature of the source is reinforced by a non-detection in the Ks-band (2.18 μm) images according to its possible extremely red Ks-L' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4-5 M Jup (at 10-17 Myr) using "hot-start" evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under program Nos. 087.C-0292, 088.C.0085, 090.C-0538, 090.C-0698, and 090.C-0728.

Bidirectional uncompressed HD video distribution over fiber employing VCSELs

DEFF Research Database (Denmark)

Estaran Tolosa, Jose Manuel; Vegas Olmos, Juan José; Rodes, G. A.

2012-01-01

We report on a bidirectional system in which VCSELs are simultaneously modulated with two uncompressed HD video signals. The results show a large power budget and a negligible penalty over 10 km long transmission links.......We report on a bidirectional system in which VCSELs are simultaneously modulated with two uncompressed HD video signals. The results show a large power budget and a negligible penalty over 10 km long transmission links....

The massive multiple system HD 64315

Science.gov (United States)

Lorenzo, J.; Simón-Díaz, S.; Negueruela, I.; Vilardell, F.; Garcia, M.; Evans, C. J.; Montes, D.

2017-10-01

Context. The O6 Vn star HD 64315 is believed to belong to the star-forming region known as NGC 2467, but previous distance estimates do not support this association. Moreover, it has been identified as a spectroscopic binary, but existing data support contradictory values for its orbital period. Aims: We explore the multiple nature of this star with the aim of determining its distance, and understanding its connection to NGC 2467. Methods: A total of 52 high-resolution spectra have been gathered over a decade. We use their analysis, in combination with the photometric data from All Sky Automated Survey and Hipparcos catalogues, to conclude that HD 64315 is composed of at least two spectroscopic binaries, one of which is an eclipsing binary. We have developed our own program to fit four components to the combined line shapes. Once the four radial velocities were derived, we obtained a model to fit the radial-velocity curves using the Spectroscopic Binary Orbit Program (SBOP). We then implemented the radial velocities of the eclipsing binary and the light curves in the Wilson-Devinney code iteratively to derive stellar parameters for its components. We were also able to analyse the non-eclipsing binary, and to derive minimum masses for its components which dominate the system flux. Results: HD 64315 contains two binary systems, one of which is an eclipsing binary. The two binaries are separated by 0.09 arcsec (or 500 AU) if the most likely distance to the system, 5 kpc, is considered. The presence of fainter companions is not excluded by current observations. The non-eclipsing binary (HD 64315 AaAb) has a period of 2.70962901 ± 0.00000021 d. Its components are hotter than those of the eclipsing binary, and dominate the appearance of the system. The eclipsing binary (HD 64315 BaBb) has a shorter period of 1.0189569 ± 0.0000008 d. We derive masses of 14.6 ± 2.3 M⊙ for both components of the BaBb system. They are almost identical; both stars are overfilling their

Kepler planet-detection mission

DEFF Research Database (Denmark)

Borucki...[], William J.; Koch, David; Buchhave, Lars C. Astrup

2010-01-01

The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet’s surface. During the first 6 weeks of observations, Kepler...... is one of the lowest-density planets (~0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets....

Alpha Elements' Effects on Planet Formation and the Hunt for Extragalactic Planets

Science.gov (United States)

Penny, Matthew; Rodriguez, Joseph E.; Beatty, Thomas; Zhou, George

2018-01-01

A star's likelihood of hosting a giant planet is well known to be strongly dependent on metallicity. However, little is known about what elements cause this correlation (e.g. bulk metals, iron, or alpha elements such as silicon and oxygen). This is likely because most planet searches target stars in the Galactic disk, and due to Galactic chemical evolution, alpha element abundances are themselves correlated with metallicity within a population. We investigate the feasibility of simultaneous transiting planet search towards the alpha-poor Sagittarius dwarf galaxy and alpha-rich Galactic bulge in a single field of view of DECam, that would enable a comparative study of planet frequency over an [alpha/Fe] baseline of ~0.4 dex. We show that a modestly sized survey could detect planet candidates in both populations, but that false positive rejection in Sgr Dwarf may be prohibitively expensive. Conversely, two-filter survey observations alone would be sufficient to rule out a large fraction of bulge false positives, enabling statistical validation of candidates with a modest follow-up investment. Although over a shorter [alpha/Fe] baseline, this survey would provide a test of whether it is alpha or iron that causes the planet metallicity correlation.

Maternal Emotions and Self-Efficacy Beliefs in Relation to Boys and Girls with AD/HD

Science.gov (United States)

Maniadaki, Katerina; Sonuga-Barke, Edmund; Kakouros, Efthymios; Karaba, Rania

2005-01-01

This study examined the impact of child gender on mothers' emotional responses to AD/HD, self-efficacy beliefs and perceived severity of AD/HD. Mothers (N = 118) of pre-schoolers were presented with a vignette describing a typical boy or girl with AD/HD and then completed three scales relating to their emotional response to AD/HD behaviour, their…

Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets

Energy Technology Data Exchange (ETDEWEB)

Bourrier, V.; Ehrenreich, D. [Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Sauverny (Switzerland); Wit, J. de [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bolmont, E. [Laboratoire AIM Paris-Saclay, CEA/DRF—CNRS—Univ. Paris Diderot—IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Stamenković, V. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Wheatley, P. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Burgasser, A. J [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States); Delrez, L. [Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Demory, B.-O. [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012, Bern (Switzerland); Gillon, M.; Jehin, E.; Grootel, V. Van [Institut dAstrophysique et de Géophysique, Université de Liège, Allée du 6 Aout 19C, B-4000 Liège (Belgium); Leconte, J. [Laboratoire dAstrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, F-33615 Pessac (France); Lederer, S. M. [NASA Johnson Space Center, 2101 NASA Parkway, Houston, Texas, 77058 (United States); Lewis, N. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218 (United States); Triaud, A. H. M. J. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2017-09-01

The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbor liquid water on their surfaces. Ultraviolet observations are essential to measuring their high-energy irradiation and searching for photodissociated water escaping from their putative atmospheres. Our new observations of the TRAPPIST-1 Ly α line during the transit of TRAPPIST-1c show an evolution of the star emission over three months, preventing us from assessing the presence of an extended hydrogen exosphere. Based on the current knowledge of the stellar irradiation, we investigated the likely history of water loss in the system. Planets b to d might still be in a runaway phase, and planets within the orbit of TRAPPIST-1g could have lost more than 20 Earth oceans after 8 Gyr of hydrodynamic escape. However, TRAPPIST-1e to h might have lost less than three Earth oceans if hydrodynamic escape stopped once they entered the habitable zone (HZ). We caution that these estimates remain limited by the large uncertainty on the planet masses. They likely represent upper limits on the actual water loss because our assumptions maximize the X-rays to ultraviolet-driven escape, while photodissociation in the upper atmospheres should be the limiting process. Late-stage outgassing could also have contributed significant amounts of water for the outer, more massive planets after they entered the HZ. While our results suggest that the outer planets are the best candidates to search for water with the JWST , they also highlight the need for theoretical studies and complementary observations in all wavelength domains to determine the nature of the TRAPPIST-1 planets and their potential habitability.

Relapse Analysis of Irradiated Patients Within the HD15 Trial of the German Hodgkin Study Group

Energy Technology Data Exchange (ETDEWEB)

Kriz, Jan; Reinartz, Gabriele [Department of Radiation Oncology, University of Münster, Münster (Germany); Dietlein, Markus; Kobe, Carsten; Kuhnert, Georg [Department of Nuclear Medicine, University of Cologne, Cologne (Germany); Haverkamp, Heinz [First Department of Internal Medicine, University of Cologne, Cologne (Germany); Haverkamp, Uwe [Department of Radiation Oncology, University of Münster, Münster (Germany); Engenhart-Cabillic, Rita [Department of Radiation Oncology, University of Marburg, Marburg (Germany); Herfarth, Klaus [Department of Radiation Oncology, University Heidelberg, Heidelberg (Germany); Lukas, Peter [Department of Radiation Oncology, University of Innsbruck, Innsbruck (Austria); Schmidberger, Heinz [Department of Radiation Oncology, University of Mainz, Mainz (Germany); Staar, Susanne [Department of Radiation Oncology, Klinikum Bremen-Mitte, Bremen (Germany); Hegerfeld, Kira [Department of Radiation Oncology, University of Münster, Münster (Germany); Baues, Christian [Department of Radiation Oncology, University of Cologne, Cologne (Germany); Engert, Andreas [First Department of Internal Medicine, University of Cologne, Cologne (Germany); Eich, Hans Theodor, E-mail: hans.eich@ukmuenster.de [Department of Radiation Oncology, University of Münster, Münster (Germany)

2015-05-01

Purpose: To determine, in the setting of advanced-stage of Hodgkin lymphoma (HL), whether relapses occur in the irradiated planning target volume and whether the definition of local radiation therapy (RT) used by the German Hodgkin Study Group (GHSG) is adequate, because there is no harmonization of field and volume definitions among the large cooperative groups in the treatment of advanced-stage HL. Methods and Materials: All patients with residual disease of ≥2.5 cm after multiagent chemotherapy (CTX) were evaluated using additional positron emission tomography (PET), and those with a PET-positive result were irradiated with 30 Gy to the site of residual disease. We re-evaluated all sites of disease before and after CTX, as well as the PET-positive residual tumor that was treated in all relapsed patients. Documentation of radiation therapy (RT), treatment planning procedures, and portal images were carefully analyzed and compared with the centrally recommended RT prescription. The irradiated sites were compared with sites of relapse using follow-up computed tomography scans. Results: A total of 2126 patients were enrolled, and 225 patients (11%) received RT. Radiation therapy documents of 152 irradiated patients (68%) were analyzed, with 28 irradiated patients (11%) relapsing subsequently. Eleven patients (39%) had an in-field relapse, 7 patients (25%) relapsed outside the irradiated volume, and an additional 10 patients (36%) showed mixed in- and out-field relapses. Of 123 patients, 20 (16%) with adequately performed RT relapsed, compared with 7 of 29 patients (24%) with inadequate RT. Conclusions: The frequency and pattern of relapses suggest that local RT to PET-positive residual disease is sufficient for patients in advanced-stage HL. Insufficient safety margins of local RT may contribute to in-field relapses.

HDAC4-Myogenin Axis As an Important Marker of HD-Related Skeletal Muscle Atrophy

Science.gov (United States)

Smeets, Cleo J. L. M.; Franklin, Sophie A.; Bondulich, Marie K.; Jolinon, Nelly; Muller, Thomas; Ahmed, Mhoriam; Dick, James R. T.; Piotrowska, Izabela; Greensmith, Linda; Smolenski, Ryszard T.; Bates, Gillian P.

2015-01-01

Skeletal muscle remodelling and contractile dysfunction occur through both acute and chronic disease processes. These include the accumulation of insoluble aggregates of misfolded amyloid proteins that is a pathological feature of Huntington’s disease (HD). While HD has been described primarily as a neurological disease, HD patients’ exhibit pronounced skeletal muscle atrophy. Given that huntingtin is a ubiquitously expressed protein, skeletal muscle fibres may be at risk of a cell autonomous HD-related dysfunction. However the mechanism leading to skeletal muscle abnormalities in the clinical and pre-clinical HD settings remains unknown. To unravel this mechanism, we employed the R6/2 transgenic and HdhQ150 knock-in mouse models of HD. We found that symptomatic animals developed a progressive impairment of the contractile characteristics of the hind limb muscles tibialis anterior (TA) and extensor digitorum longus (EDL), accompanied by a significant loss of motor units in the EDL. In symptomatic animals, these pronounced functional changes were accompanied by an aberrant deregulation of contractile protein transcripts and their up-stream transcriptional regulators. In addition, HD mouse models develop a significant reduction in muscle force, possibly as a result of a deterioration in energy metabolism and decreased oxidation that is accompanied by the re-expression of the HDAC4-DACH2-myogenin axis. These results show that muscle dysfunction is a key pathological feature of HD. PMID:25748626

Genome-wide analysis of the homeodomain-leucine zipper (HD-ZIP) gene family in peach (Prunus persica).

Science.gov (United States)

Zhang, C H; Ma, R J; Shen, Z J; Sun, X; Korir, N K; Yu, M L

2014-04-08

In this study, 33 homeodomain-leucine zipper (HD-ZIP) genes were identified in peach using the HD-ZIP amino acid sequences of Arabidopsis thaliana as a probe. Based on the phylogenetic analysis and the individual gene or protein characteristics, the HD-ZIP gene family in peach can be classified into 4 subfamilies, HD-ZIP I, II, III, and IV, containing 14, 7, 4, and 8 members, respectively. The most closely related peach HD-ZIP members within the same subfamilies shared very similar gene structure in terms of either intron/exon numbers or lengths. Almost all members of the same subfamily shared common motif compositions, thereby implying that the HD-ZIP proteins within the same subfamily may have functional similarity. The 33 peach HD-ZIP genes were distributed across scaffolds 1 to 7. Although the primary structure varied among HD-ZIP family proteins, their tertiary structures were similar. The results from this study will be useful in selecting candidate genes from specific subfamilies for functional analysis.

Homes for extraterrestrial life: extrasolar planets.

Science.gov (United States)

Latham, D W

2001-12-01

Astronomers are now discovering giant planets orbiting other stars like the sun by the dozens. But none of these appears to be a small rocky planet like the earth, and thus these planets are unlikely to be capable of supporting life as we know it. The recent discovery of a system of three planets is especially significant because it supports the speculation that planetary systems, as opposed to single orbiting planets, may be common. Our ability to detect extrasolar planets will continue to improve, and space missions now in development should be able to detect earth-like planets.

Planet traps and planetary cores: origins of the planet-metallicity correlation

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Yasuhiro [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), P.O. Box 23-141, Taipei 10641, Taiwan (China); Pudritz, Ralph E., E-mail: yasu@asiaa.sinica.edu.tw, E-mail: pudritz@physics.mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

2014-10-10

Massive exoplanets are observed preferentially around high metallicity ([Fe/H]) stars while low-mass exoplanets do not show such an effect. This so-called planet-metallicity correlation generally favors the idea that most observed gas giants at r < 10 AU are formed via a core accretion process. We investigate the origin of this phenomenon using a semi-analytical model, wherein the standard core accretion takes place at planet traps in protostellar disks where rapid type I migrators are halted. We focus on the three major exoplanetary populations—hot Jupiters, exo-Jupiters located at r ≅ 1 AU, and the low-mass planets. We show using a statistical approach that the planet-metallicity correlations are well reproduced in these models. We find that there are specific transition metallicities with values [Fe/H] = –0.2 to –0.4, below which the low-mass population dominates, and above which the Jovian populations take over. The exo-Jupiters significantly exceed the hot Jupiter population at all observed metallicities. The low-mass planets formed via the core accretion are insensitive to metallicity, which may account for a large fraction of the observed super-Earths and hot-Neptunes. Finally, a controlling factor in building massive planets is the critical mass of planetary cores (M {sub c,} {sub crit}) that regulates the onset of rapid gas accretion. Assuming the current data is roughly complete at [Fe/H] > –0.6, our models predict that the most likely value of the 'mean' critical core mass of Jovian planets is (M {sub c,} {sub crit}) ≅ 5 M {sub ⊕} rather than 10 M {sub ⊕}. This implies that grain opacities in accreting envelopes should be reduced in order to lower M {sub c,} {sub crit}.

The fate of scattered planets

Energy Technology Data Exchange (ETDEWEB)

Bromley, Benjamin C. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Rm 201, Salt Lake City, UT 84112 (United States); Kenyon, Scott J., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2014-12-01

As gas giant planets evolve, they may scatter other planets far from their original orbits to produce hot Jupiters or rogue planets that are not gravitationally bound to any star. Here, we consider planets cast out to large orbital distances on eccentric, bound orbits through a gaseous disk. With simple numerical models, we show that super-Earths can interact with the gas through dynamical friction to settle in the remote outer regions of a planetary system. Outcomes depend on planet mass, the initial scattered orbit, and the evolution of the time-dependent disk. Efficient orbital damping by dynamical friction requires planets at least as massive as the Earth. More massive, longer-lived disks damp eccentricities more efficiently than less massive, short-lived ones. Transition disks with an expanding inner cavity can circularize orbits at larger distances than disks that experience a global (homologous) decay in surface density. Thus, orbits of remote planets may reveal the evolutionary history of their primordial gas disks. A remote planet with an orbital distance ∼100 AU from the Sun is plausible and might explain correlations in the orbital parameters of several distant trans-Neptunian objects.

Search for a planet

International Nuclear Information System (INIS)

Tokovinin, A.A.

1986-01-01

The problem of search for star planets is discussed in a popular form. Two methods of search for planets are considered: astrometric and spectral. Both methods complement one another. An assumption is made that potential possessors of planets are in the first place yellow and red dwarfs with slow axial rotation. These stars are the most numerous representatives of Galaxy population

Long Term Evolution of Planetary Systems with a Terrestrial Planet and a Giant Planet

Science.gov (United States)

Georgakarakos, Nikolaos; Dobbs-Dixon, Ian; Way, Michael J.

2016-01-01

We study the long term orbital evolution of a terrestrial planet under the gravitational perturbations of a giant planet. In particular, we are interested in situations where the two planets are in the same plane and are relatively close. We examine both possible configurations: the giant planet orbit being either outside or inside the orbit of the smaller planet. The perturbing potential is expanded to high orders and an analytical solution of the terrestrial planetary orbit is derived. The analytical estimates are then compared against results from the numerical integration of the full equations of motion and we find that the analytical solution works reasonably well. An interesting finding is that the new analytical estimates improve greatly the predictions for the timescales of the orbital evolution of the terrestrial planet compared to an octupole order expansion. Finally, we briefly discuss possible applications of the analytical estimates in astrophysical problems.

CHALLENGES IN FORMING PLANETS BY GRAVITATIONAL INSTABILITY: DISK IRRADIATION AND CLUMP MIGRATION, ACCRETION, AND TIDAL DESTRUCTION

International Nuclear Information System (INIS)

Zhu Zhaohuan; Hartmann, Lee; Nelson, Richard P.; Gammie, Charles F.

2012-01-01

We present two-dimensional hydrodynamic simulations of self-gravitating protostellar disks subject to axisymmetric, continuing mass loading from an infalling envelope and irradiation from the central star to explore the growth of gravitational instability (GI) and disk fragmentation. We assume that the disk is built gradually and smoothly by the infall, resulting in good numerical convergence. We confirm that for disks around solar-mass stars, infall at high rates at radii beyond ∼50 AU leads to disk fragmentation. At lower infall rates, however, irradiation suppresses fragmentation. We find that, once formed, the fragments or clumps migrate inward on typical type I timescales of ∼2 × 10 3 yr initially, but with a stochastic component superimposed due to their interaction with the GI-induced spiral arms. Migration begins to deviate from the type I timescale when the clump becomes more massive than the local disk mass, and/or when the clump begins to form a gap in the disk. As they migrate, clumps accrete from the disk at a rate between 10 –3 and 10 –1 M J yr –1 , consistent with analytic estimates that assume a 1-2 Hill radii cross section. The eventual fates of these clumps, however, diverge depending on the migration speed: 3 out of 13 clumps in our simulations become massive enough (brown dwarf mass range) to open gaps in the disk and essentially stop migrating; 4 out of 13 are tidally destroyed during inward migration; and 6 out of 13 migrate across the inner boundary of the simulated disks. A simple analytic model for clump evolution explains the different fates of the clumps and reveals some limitations of two-dimensional simulations. Overall, our results indicate that fast migration, accretion, and tidal destruction of the clumps pose challenges to the scenario of giant planet formation by GI in situ, although we cannot address whether or not remnant solid cores can survive after tidal stripping. The models where the massive clumps are not

Direct Imaging of Warm Extrasolar Planets

International Nuclear Information System (INIS)

Macintosh, B

2005-01-01

One of the most exciting scientific discoveries in the last decade of the twentieth century was the first detection of planets orbiting a star other than our own. By now more than 130 extrasolar planets have been discovered indirectly, by observing the gravitational effects of the planet on the radial velocity of its parent star. This technique has fundamental limitations: it is most sensitive to planets close to their star, and it determines only a planet's orbital period and a lower limit on the planet's mass. As a result, all the planetary systems found so far are very different from our own--they have giant Jupiter-sized planets orbiting close to their star, where the terrestrial planets are found in our solar system. Such systems have overturned the conventional paradigm of planet formation, but have no room in them for habitable Earth-like planets. A powerful complement to radial velocity detections of extrasolar planets will be direct imaging--seeing photons from the planet itself. Such a detection would allow photometric measurements to determine the temperature and radius of a planet. Also, direct detection is most sensitive to planets in wide orbits, and hence more capable of seeing solar systems resembling our own, since a giant planet in a wide orbit does not preclude the presence of an Earth-like planet closer to the star. Direct detection, however, is extremely challenging. Jupiter is roughly a billion times fainter than our sun. Two techniques allowed us to overcome this formidable contrast and attempt to see giant planets directly. The first is adaptive optics (AO) which allows giant earth-based telescopes, such as the 10 meter W.M. Keck telescope, to partially overcome the blurring effects of atmospheric turbulence. The second is looking for young planets: by searching in the infrared for companions to young stars, we can see thermal emission from planets that are still warm with the heat of their formation. Together with a UCLA team that leads the

The Fate of Unstable Circumbinary Planets

Science.gov (United States)

Kohler, Susanna

2016-03-01

What happens to Tattooine-like planets that are instead in unstable orbits around their binary star system? A new study examines whether such planets will crash into a host star, get ejected from the system, or become captured into orbit around one of their hosts.Orbit Around a DuoAt this point we have unambiguously detected multiple circumbinary planets, raising questions about these planets formation and evolution. Current models suggest that it is unlikely that circumbinary planets would be able to form in the perturbed environment close their host stars. Instead, its thought that the planets formed at a distance and then migrated inwards.One danger such planets face when migrating is encountering ranges of radii where their orbits become unstable. Two scientists at the University of Chicago, Adam Sutherland and Daniel Fabrycky, have studied what happens when circumbinary planets migrate into such a region and develop unstable orbits.Producing Rogue PlanetsTime for planets to either be ejected or collide with one of the two stars, as a function of the planets starting distance (in AU) from the binary barycenter. Colors represent different planetary eccentricities. [Sutherland Fabrycky 2016]Sutherland and Fabrycky used N-body simulations to determine the fates of planets orbiting around a star system consisting of two stars a primary like our Sun and a secondary roughly a tenth of its size that are separated by 1 AU.The authors find that the most common fate for a circumbinary planet with an unstable orbit is ejection from the system; over 80% of unstable planets were ejected. This has interesting implications: if the formation of circumbinary planets is common, this mechanism could be filling the Milky Way with a population of free-floating, rogue planets that no longer are associated with their host star.The next most common outcome for unstable planets is collision with one of their host stars (most often the secondary), resulting inaccretion of the planet

HD 12098 and Other Results from Nainital–Cape Survey V. Girish

Indian Academy of Sciences (India)

Strömgren colours (δm1) of HD 12098, the first roAp star discovered under the ... 2, we can see an unresolved frequency very close to the alias peak (marked ... Figure 3. Lightcurve of HD 25499 observed on the night of 10th November 2003.

The HD+ dissociative recombination rate coefficient at low temperature

Directory of Open Access Journals (Sweden)

Wolf A.

2015-01-01

Full Text Available The effect of the rotational temperature of the ions is considered for low-energy dissociative recombination (DR of HD+. Merged beams measurements with HD+ ions of a rotational temperature near 300 K are compared to multichannel quantum defect theory calculations. The thermal DR rate coefficient for a Maxwellian electron velocity distribution is derived from the merged-beams data and compared to theoretical results for a range of rotational temperatures. Good agreement is found for the theory with 300 K rotational temperature. For a low-temperature plasma environment where also the rotational temperature assumes 10 K, theory predicts a considerably higher thermal DR rate coefficient. The origin of this is traced to predicted resonant structures of the collision-energy dependent DR cross section at few-meV collision energies for the particular case of HD+ ions in the rotational ground state.

Search for an evaporating ocean on the super-Earth HIP 116454b

Science.gov (United States)

Bourrier, Vincent

2017-08-01

The super-Earth HIP116454b was the first exoplanet detected by the K2 mission, in transit across a bright and nearby K1 dwarf (V=10.2, d=55 pc). The low density of the planet suggests it must have at least 30% water or a 0.5% H-He envelope. Given the strong XUV irradiation from the young (2 Gyr) host star, this H-He envelope should have been lost through evaporation in a few hundred millions year, suggesting that HIP 116454b likely contains a large mass fraction of water. The shallow transit depth makes difficult the search for water vapor in the lower atmosphere with HST/WFC3. The moderate orbital distance of this warm ( 700 K) planet favors the formation of a super-critical steam envelope, which should be promptly dissociated at high altitude by the XUV irradiation and become observable as hydrogen flowing within and beyond the Roche lobe. The host star is similar to HD 189733, host to an evaporating hot Jupiter, and numerical simulations of HIP116454b show that the hydrogen exosphere resulting from the dissociation of water is observable with HST/STIS at Ly-alpha. The detection of this exosphere would be the first signature of an evolved evaporating ocean on an extrasolar planet, as well as the first validation of internal structure models of exoplanets in this mass regime. It would also determine how to best search for water in the lower atmosphere of HIP116454b with the JWST. A non-detection of escaping hydrogen, as with 55 Cnc e and HD 97658b, would bring useful constraints on the nature of the planetary atmosphere, the evolutionary path of close-in super-Earths, and the progenitors of the rocky evaporation remnants detected by Kepler.

[Relationship between characteristic behaviors of children with AD/HD and mothers' parenting styles].

Science.gov (United States)

Mano, Shoko; Uno, Hiroyuki

2007-01-01

Previous studies have revealed that mothers of children with attention-deficit/hyperactivity disorder (AD/HD) have an authoritarian parenting style. However, the psychological process of developing an authoritarian parenting style has yet to be clearly defined. To clarify this psychological process, the present study examined the hypothesis that the characteristic behaviors of children with AD/HD initially increase the mothers' parenting stress, which influences their parenting style. Thirty-six mothers of children with AD/HD (children's mean age: 8.1 years) and the same number of controls (children's mean age: 8.4 years) participated in the present study. The mothers' parenting stress was assessed using the Japanese Parenting Stress Index. Parenting styles were assessed using the TK-style scale for evaluating the relationships between parents and children. The results indicated that the mothers of children with AD/HD had significantly higher scores than controls for all parenting stress items and negative parenting style variables (dissatisfaction, reproach, strictness, interference, inconsistency and disagreement of 10 attitudes). Stepwise multiple regression analysis revealed that the characteristic behaviors of children with AD/HD were associated with the degree of attachment in mothers, which was related to the strict and reproachful parenting style in the AD/HD group. These results suggest that mothers of children with AD/HD are likely to have a strict and reproachful parenting style as a result of a lack of attachment with the child.

The origin of high eccentricity planets: The dispersed planet formation regime for weakly magnetized disks

Directory of Open Access Journals (Sweden)

Yusuke Imaeda

2017-03-01

Full Text Available In the tandem planet formation regime, planets form at two distinct sites where solid particles are densely accumulated due to the on/off state of the magnetorotational instability (MRI. We found that tandem planet formation can reproduce the solid component distribution of the Solar System and tends to produce a smaller number of large planets through continuous pebble flow into the planet formation sites. In the present paper, we investigate the dependence of tandem planet formation on the vertical magnetic field of the protoplanetary disk. We calculated two cases of Bz=3.4×10−3 G and Bz=3.4×10−5 G at 100 AU as well as the canonical case of Bz=3.4×10−4 G. We found that tandem planet formation holds up well in the case of the strong magnetic field (Bz=3.4×10−3 G. On the other hand, in the case of a weak magnetic field (Bz=3.4×10−5 G at 100 AU, a new regime of planetary growth is realized: the planets grow independently at different places in the dispersed area of the MRI-suppressed region of r=8−30 AU at a lower accretion rate of M˙<10−7.4 M⊙yr−1. We call this the “dispersed planet formation” regime. This may lead to a system with a larger number of smaller planets that gain high eccentricity through mutual collisions.

Testing stellar evolution models with the retired A star HD 185351

DEFF Research Database (Denmark)

Hjørringgaard, J. G.; Silva Aguirre, V.; White, T. R.

2017-01-01

The physical parameters of the retired A star HD 185351 were analysed in great detail by Johnson et al. using interferometry, spectroscopy, and asteroseismology. Results from all independent methods are consistent with HD 185351 having a mass in excess of 1.5 M⊙. However, the study also showed th...

KNOW THE STAR, KNOW THE PLANET. V. CHARACTERIZATION OF THE STELLAR COMPANION TO THE EXOPLANET HOST STAR HD 177830

Energy Technology Data Exchange (ETDEWEB)

Roberts, Lewis C. Jr.; Beichman, Charles; Burruss, Rick; Cady, Eric; Lockhart, Thomas G. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA 91109 (United States); Oppenheimer, Rebecca; Brenner, Douglas; Luszcz-Cook, Statia; Nilsson, Ricky [American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Baranec, Christoph [Institute for Astronomy, University of Hawai‘i at Mānoa, Hilo, HI 96720-2700 (United States); Dekany, Richard; Hillenbrand, Lynne [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Hinkley, Sasha [School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); King, David; Parry, Ian R. [Institute of Astronomy, University of Cambridge, Madingley Road., Cambridge, CB3 OHA (United Kingdom); Pueyo, Laurent [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Sivaramakrishnan, Anand; Soummer, Rémi [Department of Astronomy, Stockholm University, AlbaNova University Center, Roslagstullsbacken 21, SE-10691 Stockholm (Sweden); Rice, Emily L., E-mail: lewis.c.roberts@jpl.nasa.gov [Department of Engineering Science and Physics, College of Staten Island, City University of New York, Staten Island, NY 10314 (United States); and others

2015-10-15

HD 177830 is an evolved K0IV star with two known exoplanets. In addition to the planetary companions it has a late-type stellar companion discovered with adaptive optics imagery. We observed the binary star system with the PHARO near-IR camera and the Project 1640 coronagraph. Using the Project 1640 coronagraph and integral field spectrograph we extracted a spectrum of the stellar companion. This allowed us to determine that the spectral type of the stellar companion is a M4 ± 1 V. We used both instruments to measure the astrometry of the binary system. Combining these data with published data, we determined that the binary star has a likely period of approximately 800 years with a semimajor axis of 100–200 AU. This implies that the stellar companion has had little or no impact on the dynamics of the exoplanets. The astrometry of the system should continue to be monitored, but due to the slow nature of the system, observations can be made once every 5–10 years.

Quantum stereodynamics study for the reaction F + HD

International Nuclear Information System (INIS)

Yu-Fang, Liu; Wei, Zhang; De-Heng, Shi; Jin-Feng, Sun

2009-01-01

This paper studies the quantum stereodynamics of the F + HD(ν = 0,j = 0) → HD + F/HF + D reaction at the collision energies of 0.52 and 0.87 kcal/mol. The quantum scattering calculations, based on Stark–Werner potential energy surfaces, show that the differential cross sections for the HF(ν' = 2) + D and DF(ν' = 3) + H channels are consistent with the recent theoretical results. Furthermore, the product rotational angular momentum orientation and alignment have been determined for some selected rovibrational states of the HF + D and DF + H channels. (atomic and molecular physics)

THREE PLANETS ORBITING WOLF 1061

Energy Technology Data Exchange (ETDEWEB)

Wright, D. J.; Wittenmyer, R. A.; Tinney, C. G.; Bentley, J. S.; Zhao, Jinglin, E-mail: duncan.wright@unsw.edu.au [Department of Astronomy and Australian Centre for Astrobiology, School of Physics, University of New South Wales, NSW 2052 (Australia)

2016-02-01

We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M{sub ⊕} minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M{sub ⊕} minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M{sub ⊕} minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H and K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.

Migration of accreting giant planets

Science.gov (United States)

Crida, A.; Bitsch, B.; Raibaldi, A.

2016-12-01

We present the results of 2D hydro simulations of giant planets in proto-planetary discs, which accrete gas at a more or less high rate. First, starting from a solid core of 20 Earth masses, we show that as soon as the runaway accretion of gas turns on, the planet is saved from type I migration : the gap opening mass is reached before the planet is lost into its host star. Furthermore, gas accretion helps opening the gap in low mass discs. Consequently, if the accretion rate is limited to the disc supply, then the planet is already inside a gap and in type II migration. We further show that the type II migration of a Jupiter mass planet actually depends on its accretion rate. Only when the accretion is high do we retrieve the classical picture where no gas crosses the gap and the planet follows the disc spreading. These results impact our understanding of planet migration and planet population synthesis models. The e-poster presenting these results in French can be found here: L'e-poster présentant ces résultats en français est disponible à cette adresse: http://sf2a.eu/semaine-sf2a/2016/posterpdfs/156_179_49.pdf.

International Deep Planet Survey, 317 stars to determine the wide-separated planet frequency

Science.gov (United States)

Galicher, R.; Marois, C.; Macintosh, B.; Zuckerman, B.; Song, I.; Barman, T.; Patience, J.

2013-09-01

Since 2000, more than 300 nearby young stars were observed for the International Deep Planet Survey with adaptive optics systems at Gemini (NIRI/NICI), Keck (Nirc2), and VLT (Naco). Massive young AF stars were included in our sample whereas they have generally been neglected in first generation surveys because the contrast and target distances are less favorable to image substellar companions. The most significant discovery of the campaign is the now well-known HR 8799 multi-planet system. This remarkable finding allows, for the first time, an estimate of the Jovians planet population at large separations (further than a few AUs) instead of deriving upper limits. During my presentation, I will present the survey showing images of multiple stars and planets. I will then propose a statistic study of the observed stars deriving constraints on the Jupiter-like planet frequency at large separations.

AD/HD: POSSIBLE DIAGNOSIS AND TREATMENT

Directory of Open Access Journals (Sweden)

Karl REICHELT

2008-12-01

Full Text Available The purpose of this paper is to show that a more exact diagnosis and dietary intervention in AD/HD (Attention Deficit/Hyperactivity Di­sor­der is possible and probable. The clinical symptom based diagnosis we suggest may be supplemented with physiological tests. A ge­netic and environmental inter-action is clearly involved and explainable using phenyl­ke­tonuria as a model.Method: Examining peer reviewed published papers on gut to blood, blood to brain inter­action and effect of interventions in AD/HD and our own studies in the field. The various treatment options are discussed.Results: It can be shown that a gut to brain activity is possible and probable, and dietary intervention is useful and probably safer than drugs. Preliminary data on a small five year follow up of dietary intervention is shown.

KNOW THE STAR, KNOW THE PLANET. II. SPECKLE INTERFEROMETRY OF EXOPLANET HOST STARS

International Nuclear Information System (INIS)

Mason, Brian D.; Hartkopf, William I.; Raghavan, Deepak; Subasavage, John P.; Roberts, Lewis C.; Turner, Nils H.; Ten Brummelaar, Theo A.

2011-01-01

A study of the host stars to exoplanets is important for understanding their environment. To that end, we report new speckle observations of a sample of exoplanet host primaries. The bright exoplanet host HD 8673 (= HIP 6702) is revealed to have a companion, although at this time we cannot definitively establish the companion as physical or optical. The observing lists for planet searches and for these observations have for the most part been pre-screened for known duplicity, so the detected binary fraction is lower than what would otherwise be expected. Therefore, a large number of double stars were observed contemporaneously for verification and quality control purposes, to ensure that the lack of detection of companions for exoplanet hosts was valid. In these additional observations, 10 pairs are resolved for the first time and 60 pairs are confirmed. These observations were obtained with the USNO speckle camera on the NOAO 4 m telescopes at both KPNO and CTIO from 2001 to 2010.

Primordial atmosphere incorporation in planetary embryos and the origin of Neon in terrestrial planets

Science.gov (United States)

Jaupart, Etienne; Charnoz, Sebatien; Moreira, Manuel

2017-09-01

The presence of Neon in terrestrial planet mantles may be attributed to the implantation of solar wind in planetary precursors or to the dissolution of primordial solar gases captured from the accretionary disk into an early magma ocean. This is suggested by the Neon isotopic ratio similar to those of the Sun observed in the Earth mantle. Here, we evaluate the second hypothesis. We use general considerations of planetary accretion and atmospheric science. Using current models of terrestrial planet formation, we study the evolution of standard planetary embryos with masses in a range of 0.1-0.2 MEarth, where MEarth is the Earth's mass, in an annular region at distances between 0.5 and 1.5 Astronomical Units from the star. We determine the characteristics of atmospheres that can be captured by such embryos for a wide range of parameters and calculate the maximum amount of Neon that can be dissolved in the planet. Our calculations may be directly transposed to any other planet. However, we only know of the amount of Neon in the Earth's solid mantle. Thus we use Earth to discuss our results. We find that the amount of dissolved Neon is too small to account for the present-day Neon contents of the Earth's mantle, if the nebular gas disk completely disappears before the largest planetary embryos grow to be ∼0.2 MEarth. This leaves solar irradiation as the most likely source of Neon in terrestrial planets for the most standard case of planetary formation models.

Gravitational Microlensing of Earth-mass Planets

DEFF Research Database (Denmark)

Harpsøe, Kennet Bomann West

It was only 17 years ago that the first planet outside of our own solar system was detected in the form of 51 Pegasi b. This planet is unlike anything in our own solar system. In fact, this planet was the first representative of a class of planets later known as “hot Jupiters”– gas giants......, i.e. it is much easier to detect high mass planets in close orbits. With these two methods it is hard to detect planets in an exo-solar system with a structure similar to our own solar system; specifically, it is hard to detect Earth-like planets in Earth-like orbits. It is presently unknown how...... common such planets are in our galaxy. There are a few other known methods for detecting exoplanets which have very different bias patterns. This thesis has been divided into two parts, treating two of these other methods. Part I is dedicated to the method of gravitational microlensing, a method...

Rocky Planet Formation: Quick and Neat

Science.gov (United States)

Kenyon, Scott J.; Najita, Joan R.; Bromley, Benjamin C.

2016-11-01

We reconsider the commonly held assumption that warm debris disks are tracers of terrestrial planet formation. The high occurrence rate inferred for Earth-mass planets around mature solar-type stars based on exoplanet surveys (˜20%) stands in stark contrast to the low incidence rate (≤2%-3%) of warm dusty debris around solar-type stars during the expected epoch of terrestrial planet assembly (˜10 Myr). If Earth-mass planets at au distances are a common outcome of the planet formation process, this discrepancy suggests that rocky planet formation occurs more quickly and/or is much neater than traditionally believed, leaving behind little in the way of a dust signature. Alternatively, the incidence rate of terrestrial planets has been overestimated, or some previously unrecognized physical mechanism removes warm dust efficiently from the terrestrial planet region. A promising removal mechanism is gas drag in a residual gaseous disk with a surface density ≳10-5 of the minimum-mass solar nebula.

The effect of planets beyond the ice line on the accretion of volatiles by habitable-zone rocky planets

International Nuclear Information System (INIS)

Quintana, Elisa V.; Lissauer, Jack J.

2014-01-01

Models of planet formation have shown that giant planets have a large impact on the number, masses, and orbits of terrestrial planets that form. In addition, they play an important role in delivering volatiles from material that formed exterior to the snow line (the region in the disk beyond which water ice can condense) to the inner region of the disk where terrestrial planets can maintain liquid water on their surfaces. We present simulations of the late stages of terrestrial planet formation from a disk of protoplanets around a solar-type star and we include a massive planet (from 1 M ⊕ to 1 M J ) in Jupiter's orbit at ∼5.2 AU in all but one set of simulations. Two initial disk models are examined with the same mass distribution and total initial water content, but with different distributions of water content. We compare the accretion rates and final water mass fraction of the planets that form. Remarkably, all of the planets that formed in our simulations without giant planets were water-rich, showing that giant planet companions are not required to deliver volatiles to terrestrial planets in the habitable zone. In contrast, an outer planet at least several times the mass of Earth may be needed to clear distant regions of debris truncating the epoch of frequent large impacts. Observations of exoplanets from radial velocity surveys suggest that outer Jupiter-like planets may be scarce, therefore, the results presented here suggest that there may be more habitable planets residing in our galaxy than previously thought.

The effect of planets beyond the ice line on the accretion of volatiles by habitable-zone rocky planets

Energy Technology Data Exchange (ETDEWEB)

Quintana, Elisa V. [SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Lissauer, Jack J., E-mail: elisa.quintana@nasa.gov [Space Science and Astrobiology Division 245-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2014-05-01

Models of planet formation have shown that giant planets have a large impact on the number, masses, and orbits of terrestrial planets that form. In addition, they play an important role in delivering volatiles from material that formed exterior to the snow line (the region in the disk beyond which water ice can condense) to the inner region of the disk where terrestrial planets can maintain liquid water on their surfaces. We present simulations of the late stages of terrestrial planet formation from a disk of protoplanets around a solar-type star and we include a massive planet (from 1 M {sub ⊕} to 1 M {sub J}) in Jupiter's orbit at ∼5.2 AU in all but one set of simulations. Two initial disk models are examined with the same mass distribution and total initial water content, but with different distributions of water content. We compare the accretion rates and final water mass fraction of the planets that form. Remarkably, all of the planets that formed in our simulations without giant planets were water-rich, showing that giant planet companions are not required to deliver volatiles to terrestrial planets in the habitable zone. In contrast, an outer planet at least several times the mass of Earth may be needed to clear distant regions of debris truncating the epoch of frequent large impacts. Observations of exoplanets from radial velocity surveys suggest that outer Jupiter-like planets may be scarce, therefore, the results presented here suggest that there may be more habitable planets residing in our galaxy than previously thought.

Azimuthal asymmetries in the debris disk around HD 61005. A massive collision of planetesimals?

Science.gov (United States)

Olofsson, J.; Samland, M.; Avenhaus, H.; Caceres, C.; Henning, Th.; Moór, A.; Milli, J.; Canovas, H.; Quanz, S. P.; Schreiber, M. R.; Augereau, J.-C.; Bayo, A.; Bazzon, A.; Beuzit, J.-L.; Boccaletti, A.; Buenzli, E.; Casassus, S.; Chauvin, G.; Dominik, C.; Desidera, S.; Feldt, M.; Gratton, R.; Janson, M.; Lagrange, A.-M.; Langlois, M.; Lannier, J.; Maire, A.-L.; Mesa, D.; Pinte, C.; Rouan, D.; Salter, G.; Thalmann, C.; Vigan, A.

2016-06-01

Context. Debris disks offer valuable insights into the latest stages of circumstellar disk evolution, and can possibly help us to trace the outcomes of planetary formation processes. In the age range 10 to 100 Myr, most of the gas is expected to have been removed from the system, giant planets (if any) must have already been formed, and the formation of terrestrial planets may be on-going. Pluto-sized planetesimals, and their debris released in a collisional cascade, are under their mutual gravitational influence, which may result into non-axisymmetric structures in the debris disk. Aims: High angular resolution observations are required to investigate these effects and constrain the dynamical evolution of debris disks. Furthermore, multi-wavelength observations can provide information about the dust dynamics by probing different grain sizes. Methods: Here we present new VLT/SPHERE and ALMA observations of the debris disk around the 40 Myr-old solar-type star HD 61005. We resolve the disk at unprecedented resolution both in the near-infrared (in scattered and polarized light) and at millimeter wavelengths. We perform a detailed modeling of these observations, including the spectral energy distribution. Results: Thanks to the new observations, we propose a solution for both the radial and azimuthal distribution of the dust grains in the debris disk. We find that the disk has a moderate eccentricity (e ~ 0.1) and that the dust density is two times larger at the pericenter compared to the apocenter. Conclusions: With no giant planets detected in our observations, we investigate alternative explanations besides planet-disk interactions to interpret the inferred disk morphology. We postulate that the morphology of the disk could be the consequence of a massive collision between ~1000 km-sized bodies at ~61 au. If this interpretation holds, it would put stringent constraints on the formation of massive planetesimals at large distances from the star. Based on observations

Classifying Planets: Nature vs. Nurture

Science.gov (United States)

Beichman, Charles A.

2009-05-01

The idea of a planet was so simple when we learned about the solar system in elementary school. Now students and professional s alike are faced with confusing array of definitions --- from "Brown Dwarfs” to "Super Jupiters", from "Super Earths” to "Terrestrial Planets", and from "Planets” to "Small, Sort-of Round Things That Aren't Really Planets". I will discuss how planets might be defined by how they formed, where they are found, or by the life they might support.

HD 101065, the Most Peculiar Star: First Results from Precise Radial ...

Indian Academy of Sciences (India)

Abstract. In this paper we discuss the prospects for asteroseismology with spatial resolution and motivate studies of the most chemically peculiar. roAp star HD 101065. We present the first results from a high-precision radial velocity (RV) study of HD 101065 based on data spanning four nights that were acquired using the ...

Characterization of Runella slithyformis HD-Pnk, a bifunctional DNA/RNA end-healing enzyme composed of an N-terminal 2',3' -phosphoesterase HD domain and a C-terminal 5' -OH polynucleotide kinase domain.

Science.gov (United States)

Munir, Annum; Shuman, Stewart

2016-11-28

5' and 3' end healing are key steps in nucleic acid break repair in which 5' -OH ends are phosphorylated by a polynucleotide kinase and 3' -PO 4 or 2',3' -cyclic-PO 4 ends are hydrolyzed by a phosphoesterase to generate the 5' -PO 4 and 3' -OH termini required for sealing by classic polynucleotide ligases. End healing and sealing enzymes are present in diverse bacterial taxa, often organized as modular units within a single multifunctional polypeptide or as subunits of a repair complex. Here we identify and characterize Runella slithyformis HD-Pnk as a novel bifunctional end-healing enzyme composed of an N-terminal 2',3' -phosphoesterase HD domain and a C-terminal 5' -OH polynucleotide kinase P-loop domain. HD-Pnk phosphorylates 5' -OH polynucleotides (9-mers or longer) in the presence of magnesium and any NTP donor. HD-Pnk dephosphorylates RNA 2',3' -cyclic phosphate, RNA 3' -phosphate, RNA 2' -phosphate, and DNA 3' -phosphate ends in the presence of a transition metal cofactor, which can be nickel, copper or cobalt. HD-Pnkp homologs are present in genera from eleven bacterial phyla and are often encoded in an operon with a putative ATP-dependent polynucleotide ligase. The present study provides insights to the diversity of nucleic acid repair strategies via the characterization of Runella slithyformis HD-Pnkp as the exemplar of a novel clade of dual 5' and 3' end-healing enzymes that phosphorylate 5' -OH termini and dephosphorylate 2',3' -cyclic-PO 4 , 3' -PO 4 , and 2' -PO 4 ends. The distinctive feature of HD-Pnk is its domain composition: a fusion of an N-terminal HD phosphohydrolase module to a C-terminal P-loop polynucleotide kinase module. Homologs of Runella HD-Pnk with the same domain composition, domain order, and similar polypeptide size are distributed widely among genera from eleven bacterial phyla. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

AtHD2D gene plays a role in plant growth, development and response to abiotic stresses in Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Zhaofen eHan

2016-03-01

Full Text Available Abstracts: The histone deacetylases play important roles in the regulation of gene expression and the subsequent control of a number of important biological processes, including those involved in the response to environmental stress. A specific group of histone deacetylase genes, HD2, is present in plants. In Arabidopsis, HD2s include HD2A, HD2B, HD2C and HD2D. Previous research showed that HD2A, HD2B and HD2C are more related in terms of expression and function, but not HD2D. In this report, we studied different aspects of AtHD2D in Arabidopsis with respect to plant response to drought and other abiotic stresses. Bioinformatics analysis indicates that HD2D is distantly related to other HD2 genes. Transient expression in Nicotiana benthamiana and stable expression in Arabidopsis of AtHD2D fused with gfp showed that AtHD2D was expressed in the nucleus. Overexpression of AtHD2D resulted in developmental changes including fewer main roots, more lateral roots, and a higher root:shoot ratio. Seed germination and plant flowering time were delayed in transgenic plants expressing AtHD2D, but these plants exhibited higher degrees of tolerance to abiotic stresses, including drought, salt and cold stresses. Physiological studies indicated that the malondialdehyde (MDA content was high in wild-type plants but in plants overexpressing HD2D the MDA level increased slowly in response to stress conditions of drought, cold, and salt stress. Furthermore, electrolyte leakage in leaf cells of wild type plants increased but remained stable in transgenic plants. Our results indicate that AtHD2D is unique among HD2 genes and it plays a role in plant growth and development regulation and these changes can modulate plant stress responses.

Kepler-91b: a planet at the end of its life. Planet and giant host star properties via light-curve variations

Science.gov (United States)

Lillo-Box, J.; Barrado, D.; Moya, A.; Montesinos, B.; Montalbán, J.; Bayo, A.; Barbieri, M.; Régulo, C.; Mancini, L.; Bouy, H.; Henning, T.

2014-02-01

the stellar atmosphere at the pericentre. We also detected three small dims in the phase-folded light curve. The combination of two of them agrees with the theoretical characteristics expected for secondary eclipse. Conclusions: Kepler-91b could be the previous stage of the planet engulfment, which has recently been detected for BD+48 740. Our estimations show that Kepler-91b will be swallowed by its host star in less than 55 Myr. Among the confirmed planets around giant stars, this is the closest to its host star. At pericentre, the star subtends an angle of 48°, covering around 10% of the sky as seen from the planet. The planetary atmosphere seems to be inflated probably due to the high stellar irradiation. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut fur Astronomie (Heidelberg) and the Instituto de Astrofísica de Andalucía (IAA-CSIC, Granada).Appendix A is available in electronic form at http://www.aanda.org

UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION

Energy Technology Data Exchange (ETDEWEB)

Rugheimer, S.; Sasselov, D. [Harvard Smithsonian Center for Astrophysics, 60 Garden st., 02138 MA Cambridge (United States); Segura, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México (Mexico); Kaltenegger, L., E-mail: srugheimer@cfa.harvard.edu [Carl Sagan Institute, Cornell University, Ithaca, NY 14853 (United States)

2015-06-10

The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UV flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth–Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth–Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments.

UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION

International Nuclear Information System (INIS)

Rugheimer, S.; Sasselov, D.; Segura, A.; Kaltenegger, L.

2015-01-01

The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UV flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth–Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth–Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments

Profile of He I lambda5876 in the P-Cygni-type of star HD 152408

International Nuclear Information System (INIS)

Walborn, N.R.

1975-01-01

The blue-shifted absorption component of the P-Cygni profile at He I lambda 5876 in HD 152408 (O8: Iafpe) has been found to be extremely broad, extending -1000 km sec -1 from the emission maximum. This unusual profile is probably due to overpopulation of the lower level of lambda 5876, which permits it to form throughout a greater extent of the expanding atmosphere than most other lines. This observation confirms Hutchings' identification of very large velocities in the blue-violet spectrum of HD 152408, and in particular his interpretation of a similar feature at He I lambda 3889, which is metastable. The lambda 5876 profile in HD 152408 is compared to those in the similar but less extreme P-Cygni star HD 151804 (O8 Iaf), and in the Wolf-Rayet star HD 151932 (WN7-A). The similarity between the absorption components in HD 152408 and the WN star is striking

Planet formation in Binaries

OpenAIRE

Thebault, Ph.; Haghighipour, N.

2014-01-01

Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review her...

Evidence for Abnormal H α Variability During Near-transit Observations of HD 189733 b

International Nuclear Information System (INIS)

Cauley, P. Wilson; Redfield, Seth; Jensen, Adam G.

2017-01-01

Changes in levels of stellar activity can mimic absorption signatures in transmission spectra from circumplanetary material. Thus, it is critical to understand the frequency and magnitude of these changes in order to attribute any particular signal to the circumplanetary environment. We present short-cadence, high-resolution out-of-transit H α spectra for the hot Jupiter host HD 189733 in order to establish the frequency and magnitude of intrinsic stellar variations in the H α line core. We find that changes in the line core strength similar to those observed immediately pre- and post-transit in two independent data sets are uncommon. This suggests that the observed near-transit signatures are either due to absorption of circumplanetary material or they occur preferentially in time, very near planetary transits. In either case, the evidence for abnormal H α variability is strengthened, though the short-cadence out-of-transit data do not argue for circumplanetary absorption versus stellar activity caused by a star–planet interaction. Further out-of-transit monitoring at higher signal-to-noise would be useful to more strictly constrain the frequency of the near-transit changes in the H α line core.

Evidence for Abnormal H α Variability During Near-transit Observations of HD 189733 b

Energy Technology Data Exchange (ETDEWEB)

Cauley, P. Wilson; Redfield, Seth [Wesleyan University Astronomy Department, Van Vleck Observatory, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Jensen, Adam G., E-mail: pcauley@wesleyan.edu [University of Nebraska-Kearney Department of Physics and Astronomy, 24011 11th Avenue, Kearney, NE 68849 (United States)

2017-04-01

Changes in levels of stellar activity can mimic absorption signatures in transmission spectra from circumplanetary material. Thus, it is critical to understand the frequency and magnitude of these changes in order to attribute any particular signal to the circumplanetary environment. We present short-cadence, high-resolution out-of-transit H α spectra for the hot Jupiter host HD 189733 in order to establish the frequency and magnitude of intrinsic stellar variations in the H α line core. We find that changes in the line core strength similar to those observed immediately pre- and post-transit in two independent data sets are uncommon. This suggests that the observed near-transit signatures are either due to absorption of circumplanetary material or they occur preferentially in time, very near planetary transits. In either case, the evidence for abnormal H α variability is strengthened, though the short-cadence out-of-transit data do not argue for circumplanetary absorption versus stellar activity caused by a star–planet interaction. Further out-of-transit monitoring at higher signal-to-noise would be useful to more strictly constrain the frequency of the near-transit changes in the H α line core.

Planets in a Room

Science.gov (United States)

Giacomini, l.; Aloisi, F.; De Angelis, I.

2017-09-01

Teaching planetary science using a spherical projector to show the planets' surfaces is a very effective but usually very expensive idea. Whatsmore, it usually assumes the availability of a dedicated space and a trained user. "Planets in a room" is a prototypal low cost version of a small, spherical projector that teachers, museum, planetary scientists and other individuals can easily build and use on their own, to show and teach the planets The project of "Planets in a Room" was made by the italian non-profit association Speak Science with the collaboration of INAF-IAPS of Rome and the Roma Tre University (Dipartimento di Matematica e Fisica). This proposal was funded by the Europlanet Outreach Funding Scheme in 2016. "Planets in a room" will be presented during EPSC 2017 to give birth to the second phase of the project, when the outreach and research community will be involved and schools from all over Europe will be invited to participate with the aim of bringing planetary science to a larger audience.

DISCOVERY OF SMALL-SCALE SPIRAL STRUCTURES IN THE DISK OF SAO 206462 (HD 135344B): IMPLICATIONS FOR THE PHYSICAL STATE OF THE DISK FROM SPIRAL DENSITY WAVE THEORY

Energy Technology Data Exchange (ETDEWEB)

Muto, T.; Takeuchi, T. [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Grady, C. A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland CA 96002 (United States); Hashimoto, J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Fukagawa, M. [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Hornbeck, J. B. [Department of Physics and Astronomy, University of Louisville, Louisville, KY 40292 (United States); Sitko, M. [Space Science Institute, 4750 Walnut St., Suite 205, Boulder, CO 80301 (United States); Russell, R. [The Aerospace Corporation, Los Angeles, CA 90009 (United States); Werren, C. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 (United States); Cure, M. [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Currie, T. [ExoPlanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ohashi, N. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Okamoto, Y.; Momose, M. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Honda, M. [Department of Information Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Inutsuka, S. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602 (Japan); Dong, R.; Brandt, T. [Department of Astrophysical Sciences, Princeton University, NJ08544 (United States); Abe, L. [Laboratoire Lagrange, UMR7293, Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d' Azur, 06300 Nice (France); Brandner, W., E-mail: muto@geo.titech.ac.jp [Max Planck Institute for Astronomy, Heidelberg (Germany); and others

2012-04-01

We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of a dust-depleted cavity at r {<=} 46 AU, our observations reveal the presence of scattered light components as close as 0.''2 ({approx} 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0.''5 ({approx} 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h {approx} 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.

DISCOVERY OF SMALL-SCALE SPIRAL STRUCTURES IN THE DISK OF SAO 206462 (HD 135344B): IMPLICATIONS FOR THE PHYSICAL STATE OF THE DISK FROM SPIRAL DENSITY WAVE THEORY

International Nuclear Information System (INIS)

Muto, T.; Takeuchi, T.; Grady, C. A.; Hashimoto, J.; Fukagawa, M.; Hornbeck, J. B.; Sitko, M.; Russell, R.; Werren, C.; Curé, M.; Currie, T.; Ohashi, N.; Okamoto, Y.; Momose, M.; Honda, M.; Inutsuka, S.; Dong, R.; Brandt, T.; Abe, L.; Brandner, W.

2012-01-01

We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of a dust-depleted cavity at r ≤ 46 AU, our observations reveal the presence of scattered light components as close as 0.''2 (∼ 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0.''5 (∼ 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h ∼ 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.

Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B): Implications for the Physical State of the Disk from Spiral Density Wave Theory

Science.gov (United States)

Grady, C. A.; Currie, T.

2012-01-01

We present high-resolution, H-band, imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of the dust-depleted cavity at r approximates 46 AU, our observations reveal the presence of scattered light components as close as 0".2 (approx 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0".5 (approx 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h approx 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelengths observations.

Trapping planets in an evolving protoplanetary disk: preferred time, locations and planet mass

OpenAIRE

Baillié, Kévin; Charnoz, Sébastien; Pantin, Éric

2016-01-01

Planet traps are necessary to prevent forming planets from falling onto their host star by type I migration. Surface mass density and temperature gradient irregularities favor the apparition of traps and deserts. Such features are found at the dust sublimation lines and heat transition barriers. We study how planets may remain trapped or escape as they grow and as the disk evolves. We model the temporal viscous evolution of a protoplanetary disk by coupling its dynamics, thermodynamics, geome...

Increased H2CO production in the outer disk around HD 163296

Science.gov (United States)

Carney, M. T.; Hogerheijde, M. R.; Loomis, R. A.; Salinas, V. N.; Öberg, K. I.; Qi, C.; Wilner, D. J.

2017-09-01

Context. The gas and dust in circumstellar disks provide the raw materials to form planets. The study of organic molecules and their building blocks in such disks offers insight into the origin of the prebiotic environment of terrestrial planets. Aims: We aim to determine the distribution of formaldehyde, H2CO, in the disk around HD 163296 to assess the contribution of gas- and solid-phase formation routes of this simple organic. Methods: Three formaldehyde lines were observed (H2CO 303-202, H2CO 322-221, and H2CO 321-220) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5″ (60 AU) spatial resolution. Different parameterizations of the H2CO abundance were compared to the observed visibilities, using either a characteristic temperature, a characteristic radius or a radial power law index to describe the H2CO chemistry. Similar models were applied to ALMA Science Verification data of C18O. In each scenario, χ2 minimization on the visibilities was used to determine the best-fit model in each scenario. Results: H2CO 303-202 was readily detected via imaging, while the weaker H2CO 322-221 and H2CO 321-220 lines required matched filter analysis to detect. H2CO is present throughout most of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of the H2CO emission is likely caused by an optically thick dust continuum. The H2CO radial intensity profile shows a peak at 100 AU and a secondary bump at 300 AU, suggesting increased production in the outer disk. In all modeling scenarios, fits to the H2CO data show an increased abundance in the outer disk. The overall best-fit H2CO model shows a factor of two enhancement beyond a radius of 270 ± 20 AU, with an inner abundance (relative to H2) of 2 - 5 × 10-12. The H2CO emitting region has a lower limit on the kinetic temperature of T> 20 K. The C18O modeling suggests an order of magnitude depletion of C18O in the outer disk and an abundance of 4 - 12 × 10-8 in the inner disk

White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

Science.gov (United States)

Levinton, Douglas B.; Cash, Webster C.; Gleason, Brian; Kaiser, Michael J.; Levine, Sara A.; Lo, Amy S.; Schindhelm, Eric; Shipley, Ann F.

2007-01-01

A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.

Extrasolar Planets in the Classroom

Science.gov (United States)

George, Samuel J.

2011-01-01

The field of extrasolar planets is still, in comparison with other astrophysical topics, in its infancy. There have been about 300 or so extrasolar planets detected and their detection has been accomplished by various different techniques. Here we present a simple laboratory experiment to show how planets are detected using the transit technique.…

Mechanical Analysis of the Nb3Sn Dipole Magnet HD1

International Nuclear Information System (INIS)

Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich, Daniel R.; Gourlay, Steve A.; Hannaford, Charles R.; Hafalia, Aurelio R.; Lietzke, Alan F.; Mattafirri, Sara; Sabbi, Gianluca

2005-01-01

The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has recently fabricated and tested HD1, a Nb3Sn dipole magnet. The magnet reached a 16 T field, and exhibited training quenches in the end regions and in the straight section. After the test, HD1 was disassembled and inspected, and a detailed 3D finite element mechanical analysis was done to investigate for possible quench triggers. The study led to minor modifications to mechanical structure and assembly procedure, which were verified in a second test (HD1b). This paper presents the results of the mechanical analysis, including strain gauge measurements and coil visual inspection. The adjustments implemented in the magnet structure are reported and their effect on magnet training discussed

Mechanical analysis of the Nb3Sn dipole magnet HD1

International Nuclear Information System (INIS)

Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich, Daniel R.; Gourlay, Steve A.; Hannaford, Carles R.; Hafalia, Aurelio R.; Lietzke, Alan F.; Mattafirri, Sara; Sabbi, Gianluca

2005-01-01

The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has recently fabricated and tested HD1, a Nb 3 Sn dipole magnet. The magnet reached a 16 T field, and exhibited training quenches in the end regions and in the straight section. After the test, HD1 was disassembled and inspected, and a detailed 3D finite element mechanical analysis was done to investigate for possible quench triggers. The study led to minor modifications to mechanical structure and assembly procedure, which were verified in a second test (HD1b). This paper presents the results of the mechanical analysis, including strain gauge measurements and coil visual inspection. The adjustments implemented in the magnet structure are reported and their effect on magnet training discussed

The protoplanetary system HD 100546 in Hα polarized light from SPHERE/ZIMPOL. A bar-like structure across the disk gap?

Science.gov (United States)

Mendigutía, I.; Oudmaijer, R. D.; Garufi, A.; Lumsden, S. L.; Huélamo, N.; Cheetham, A.; de Wit, W. J.; Norris, B.; Olguin, F. A.; Tuthill, P.

2017-12-01

Context. HD 100546 is one of the few known pre-main-sequence stars that may host a planetary system in its disk. Aims: This work aims to contribute to our understanding of HD 100546 by analyzing new polarimetric images with high spatial resolution. Methods: Using VLT/SPHERE/ZIMPOL with two filters in Hα and the adjacent continuum, we have probed the disk gap and the surface layers of the outer disk, covering a region disk are more polarized than the SW and NE regions. This asymmetry can be explained from a preferential scattering angle close to 90° and is consistent with previous polarization images. The outer disk in our observations extends from 13 ± 2 to 45 ± 9 au, with a position angle and inclination of 137 ± 5° and 44 ± 8°, respectively. The comparison with previous estimates suggests that the disk inclination could increase with the stellocentric distance, although the different measurements are still consistent within the error bars. In addition, no direct signature of the innermost candidate companion is detected from the polarimetric data, confirming recent results that were based on intensity imagery. We set an upper limit to its mass accretion rate 3σ) of a 20 au bar-like structure that crosses the gap through the central region of HD 100546. Conclusions: In the absence of additional data, it is tentatively suggested that the bar could be dust dragged by infalling gas that radially flows from the outer disk to the inner region. This could represent an exceptional case in which a small-scale radial inflow is observed in a single system. If this scenario is confirmed, it could explain the presence of atomic gas in the inner disk that would otherwise accrete on to the central star on a timescale of a few months/years, as previously indicated from spectro-interferometric data, and could be related with additional (undetected) planets.

The Discovery of HD 37605c and a Dispositive Null Detection of Transits of HD 37605b

DEFF Research Database (Denmark)

Xuesong Wang, Sharon; Wright, Jason T.; Cochran, William

2012-01-01

the predicted ephemeris, we performed a transit search for HD 37605b with the photometric data taken by the T12 0.8-m Automatic Photoelectric Telescope (APT) and the Microvariability and Oscillations of Stars (MOST) satellite. Though the APT photometry did not capture the transit window, it characterized...

Extrasolar planets searches today and tomorrow

CERN Multimedia

2000-01-01

So far the searches for extrasolar planets have found 40 planetary companions orbiting around nearby stars. In December 1999 a transit has been observed for one of them, providing the first independent confirmation of the reality of close-in planets as well as a measurement of its density. The techniques used to detect planets are limited and the detection threshold is biased but a first picture of the planet diversity and distribution emerges. Results of the search for extra-solar planets and their impacts on planetary formation will be reviewed. Future instruments are foreseen to detect Earth-like planets and possible signatures of organic activity. An overview of these future projects will be presented and more particularly the Darwin-IRSI mission studied by ESA for Horizon 2015.

Three-dimensional (3D) structure prediction and function analysis of the chitin-binding domain 3 protein HD73_3189 from Bacillus thuringiensis HD73.

Science.gov (United States)

Zhan, Yiling; Guo, Shuyuan

2015-01-01

Bacillus thuringiensis (Bt) is capable of producing a chitin-binding protein believed to be functionally important to bacteria during the stationary phase of its growth cycle. In this paper, the chitin-binding domain 3 protein HD73_3189 from B. thuringiensis has been analyzed by computer technology. Primary and secondary structural analyses demonstrated that HD73_3189 is negatively charged and contains several α-helices, aperiodical coils and β-strands. Domain and motif analyses revealed that HD73_3189 contains a signal peptide, an N-terminal chitin binding 3 domains, two copies of a fibronectin-like domain 3 and a C-terminal carbohydrate binding domain classified as CBM_5_12. Moreover, analysis predicted the protein's associated localization site to be the cell wall. Ligand site prediction determined that amino acid residues GLU-312, TRP-334, ILE-341 and VAL-382 exposed on the surface of the target protein exhibit polar interactions with the substrate.

Symmetry Breakdown in Ground State Dissociation of HD+

International Nuclear Information System (INIS)

Ben-Itzhak, I.; Wells, E.; Carnes, K. D.; Krishnamurthi, Vidhya; Weaver, O. L.; Esry, B. D.

2000-01-01

Experimental studies of the dissociation of the electronic ground state of HD + following ionization of HD by fast proton impact indicate that the H + +D 1s dissociation channel is more likely than the H1s+D + dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1sσ state 3.7 meV lower than the 2pσ state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1sσ to 2pσ transitions. (c) 2000 The American Physical Society

A septet of Earth-sized planets

Science.gov (United States)

Triaud, Amaury; SPECULOOS Team; TRAPPIST-1 Team

2017-10-01

Understanding the astronomical requirements for life to emerge, and to persist, on a planet is one of the most important and exciting scientific endeavours, yet without empirical answers. To resolve this, multiple planets whose sizes and surface temperatures are similar to the Earth, need to be discovered. Those planets also need to possess properties enabling detailed atmospheric characterisation with forthcoming facilities, from which chemical traces produced by biological activity can in principle be identified.I will describe a dedicated search for such planets called SPECULOOS. Our first detection is the TRAPPIST-1 system. Intensive ground-based and space-based observations have revealed that at least seven planets populate this system. We measured their radii and obtained first estimates of their masses thanks to transit-timing variations. I will describe our on-going observational efforts aiming to reduce our uncertainties on the planet properties. The incident flux on the planets ranges from Mercury to Ceres, comprising the Earth, and permitting climatic comparisons between each of those worlds such as is not possible within our Solar system. All seven planets have the potential to harbour liquid water on at least a fraction of their surfaces, given some atmospheric and geological conditions.

A Petunia Homeodomain-Leucine Zipper Protein, PhHD-Zip, Plays an Important Role in Flower Senescence

Science.gov (United States)

Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S.; Jiang, Cai-Zhong

2014-01-01

Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence. PMID:24551088

A Petunia homeodomain-leucine zipper protein, PhHD-Zip, plays an important role in flower senescence.

Science.gov (United States)

Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S; Jiang, Cai-Zhong

2014-01-01

Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence.

A Petunia homeodomain-leucine zipper protein, PhHD-Zip, plays an important role in flower senescence.

Directory of Open Access Journals (Sweden)

Xiaoxiao Chang

Full Text Available Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO, and ABA (NCED biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29 was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA and abiotic stresses (dehydration, NaCl and cold. Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence.

YOUNG SOLAR SYSTEM's FIFTH GIANT PLANET?

International Nuclear Information System (INIS)

Nesvorný, David

2011-01-01

Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside ∼15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

Young Solar System's Fifth Giant Planet?

Science.gov (United States)

Nesvorný, David

2011-12-01

Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside ~15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

Habitable Planets for Man

National Research Council Canada - National Science Library

Dole, Stephen H

2007-01-01

..., and discusses how to search for habitable planets. Interestingly for our time, he also gives an appraisal of the earth as a planet and describes how its habitability would be changed if some of its basic properties were altered...

The circumstances of minor planet discovery

International Nuclear Information System (INIS)

Pilcher, F.

1989-01-01

The circumstances of discoveries of minor planets are presented in tabular form. Complete data are given for planets 2125-4044, together with notes pertaining to these planets. Information in the table includes the permanent number; the official name; for planets 330 and forward, the table includes the provisional designation attached to the discovery apparition and the year, month, the day of discovery, and the discovery place

The accretion of migrating giant planets

Science.gov (United States)

Dürmann, Christoph; Kley, Wilhelm

2017-02-01

Aims: Most studies concerning the growth and evolution of massive planets focus either on their accretion or their migration only. In this work we study both processes concurrently to investigate how they might mutually affect one another. Methods: We modeled a two-dimensional disk with a steady accretion flow onto the central star and embedded a Jupiter mass planet at 5.2 au. The disk is locally isothermal and viscosity is modeled using a constant α. The planet is held on a fixed orbit for a few hundred orbits to allow the disk to adapt and carve a gap. After this period, the planet is released and free to move according to the gravitational interaction with the gas disk. The mass accretion onto the planet is modeled by removing a fraction of gas from the inner Hill sphere, and the removed mass and momentum can be added to the planet. Results: Our results show that a fast migrating planet is able to accrete more gas than a slower migrating planet. Utilizing a tracer fluid we analyzed the origin of the accreted gas originating predominantly from the inner disk for a fast migrating planet. In the case of slower migration, the fraction of gas from the outer disk increases. We also found that even for very high accretion rates, in some cases gas crosses the planetary gap from the inner to the outer disk. Our simulations show that the crossing of gas changes during the migration process as the migration rate slows down. Therefore, classical type II migration where the planet migrates with the viscous drift rate and no gas crosses the gap is no general process but may only occur for special parameters and at a certain time during the orbital evolution of the planet.

Characterizing Debris Disks in the Late Stages of Planet Formation

Science.gov (United States)

White, Jacob

2018-01-01

The planet formation process shapes the morphology and grain size distribution of circumstellar disks, encoding the formation history of a given system. Remnants of planet formation, such as comets and asteroids, collisionally evolve and can replenish the dust and small solids that would otherwise be cleared on short timescales. These grains are observed through reprocessed starlight at submm to cm wavelengths.The spectrum of the mm/cm emission reveals details of the grain population. However, one confounding parameter in studying these grains around stars is the stars themselves. The emission from stars in the mm/cm is nontrivial and generally not well-constrained. I will present examples of debris systems (HD 141569 and Fomalhaut) studied by ALMA and the VLA, in which unconstrained stellar emission may be contributing to the observed flux densities. Such contamination in turn biases the inferred emission from the disk and the corresponding dust properties. In some cases, the behavior of the observed A/B stars can exhibit an emission profile that has similarities to that of the Sun's mm/cm emission, although the same processes are not thought to necessarily occur in the atmospheres of massive stars.To address the uncertainty in stellar emission at mm/cm wavelengths, we present ongoing radio observations (JCMT, SMA, VLA) of Sirius A, which is a bright, nearby star with no known debris. We seek to use this system to set an observationally determined standard for stellar atmosphere modeling and debris disk studies around A stars, as well as to take the first step toward characterizing potential intrinsic uncertainty in stellar emission at these wavelengths. This talk will highlight the effort to characterize stellar atmospheres through a project known as MESAS (Measuring the Emission of Stellar Atmospheres at Submillimeter/millimeter wavelengths) which is imperative to the success of current and future debris disk studies.

AD/HD Symptoms and Conduct Problems: Similarities and Differences in Maternal Perceptions