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Sample records for algol

  1. Programming Algol

    CERN Document Server

    Malcolme-Lawes, D J

    2014-01-01

    Programming - ALGOL describes the basics of computer programming using Algol. Commands that could be added to Algol and could increase its scope are described, including multiplication and division and the use of brackets. The idea of labeling or naming a command is also explained, along with a command allowing two alternative results. Most of the important features of Algol syntax are discussed, and examples of compound statements (that is, sets of commands enclosed by a begin ... end command) are given.Comprised of 11 chapters, this book begins with an introduction to the digital computer an

  2. Ultraviolet photometry and spectrophotometry of Algol

    Science.gov (United States)

    Eaton, J. A.

    1975-01-01

    OAO-2 blue and UV light curves and spectrophotometric observations are used to establish effective temperatures and luminosities for the three components of the eclipsing Algol (beta Persei) system. An essentially complete energy distribution is given for Algol, and the fundamental properties - geometrical quantities, wavelength-dependent quantities and derived astrophysical quantities - are presented for the star.

  3. Did the ancient egyptians discover Algol?

    Science.gov (United States)

    Jetsu, L.; Porceddu, S.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Markkanen, T.; Toivari-Viitala, J.

    2013-02-01

    Fabritius discovered the first variable star, Mira, in 1596. Holwarda determined the 11 months period of Mira in 1638. Montanari discovered the next variable star, Algol, in 1669. Its period, 2.867 days, was determined by Goodricke (178). Algol was associated with demon-like creatures, "Gorgon" in ancient Greek and "ghoul" in ancient Arab mythology. This indicates that its variability was discovered much before 1669 (Wilk 1996), but this mythological evidence is ambiguous (Davis 1975). For thousands of years, the Ancient Egyptian Scribes (AES) observed stars for timekeeping in a region, where there are nearly 300 clear nights a year. We discovered a significant periodicity of 2.850 days in their calendar for lucky and unlucky days dated to 1224 BC, "the Cairo Calendar". Several astrophysical and astronomical tests supported our conclusion that this was the period of Algol three millennia ago. The "ghoulish habits" of Algol could explain this 0.017 days period increase (Battersby 2012).

  4. Accretion disks in Algols: progenitors and evolution

    CERN Document Server

    Van Rensbergen, W

    2016-01-01

    There are only a few Algols with measured accretion disk parameters. These measurements provide additional constraints for tracing the origin of individual systems, narrowing down the initial parameter space. We investigate the origin and evolution of 6 Algol systems with accretion disks to find the initial parameters and evolutionary constraints for them. With a modified binary evolution code, series of close binary evolution are calculated to obtain the best match for observed individual systems. Initial parameters for 6 Algol systems with accretion disks were determined matching both the present system parameters and the observed disk characteristics. When RLOF starts during core hydrogen burning of the donor, the disk lifetime was found to be short. The disk luminosity is comparable to the luminosity of the gainer during a large fraction of the disk lifetime.

  5. On extensions of ALGOL-like languages

    DEFF Research Database (Denmark)

    Skyum, Sven

    1974-01-01

    In this paper we introduce the notion of a level grammar and a level language. We define an extension to the extended definable sets and we characterize ALGOL-like languages, extended definable sets, and extensions of those as languages generated by level grammars with different kinds...

  6. Customer Buying Behavior : Case Study: Algol Technics

    OpenAIRE

    Weckman, Nina

    2009-01-01

    The purpose of this study is to research the customer buying behavior in a specific market. This thesis is made for a subgroup of Algol Technics which specializes in the marketing of driver seats. The research areas included brand recognition, price and quality, as well as the communications channels. The theoretical framework presented consists of the marketing strategies, marketing mix, Porter’s five forces analysis, customer relationship marketing, and market analysis. The case compan...

  7. Spectroscopically resolving the Algol triple system

    CERN Document Server

    Kolbas, V; Southworth, J; Lee, C -U; Lee, D -J; Lee, J W; Kim, S -L; Kim, H -I; Smalley, B; Tkachenko, A

    2015-01-01

    Algol ($\\beta$ Persei) is the prototypical semi-detached eclipsing binary and a hierarchical triple system. From 2006 to 2010 we obtained 121 high-resolution and high-S/N \\'{e}chelle spectra of this object. Spectral disentangling yields the individual spectra of all three stars, and greatly improved elements both the inner and outer orbits. We find masses of $M_{\\rm A} = 3.39\\pm0.06$ M$_\\odot$, $M_{\\rm B} = 0.770\\pm0.009$ M$_\\odot$ and $M_{\\rm C} = 1.58\\pm0.09$ M$_\\odot$. The disentangled spectra also give the light ratios between the components in the $B$ and $V$ bands. Atmospheric parameters for the three stars are determined, including detailed elemental abundances for Algol A and Algol C. We find the following effective temperatures: $T_{\\rm A} = 12\\,550\\pm120$ K, $T_{\\rm B} = 4900\\pm300$ K and $T_{\\rm C} = 7550\\pm250$ K. The projected rotational velocities are $v_{\\rm A} \\sin i_{\\rm A} = 50.8\\pm0.8$ km/s, $v_{\\rm B} \\sin i_{\\rm B} = 62\\pm2$ km/s and $v_{\\rm C} \\sin i_{\\rm C} = 12.4\\pm0.6$ km/s. This is t...

  8. Syntax analysis of an Algol extension for a vector machine

    International Nuclear Information System (INIS)

    This research thesis addresses the study of the definition of vector extensions aimed at extending the Algol 60 programming language. This syntax analysis is the first of the three main components of a future extended Algol compiler which is to operate on a vector machine, the other components being the semantic analysis and the code generation. The author presents the characteristics of the vector machine and the most interesting statements, defines the syntax of Algol and of vector extensions, and presents some examples. He presents the general philosophy adopted for this analysis, some options adopted for the definition of algorithms within the frame of a lexicographic analysis and of syntax analysis

  9. ALGOL compiler. Syntax and semantic analysis

    International Nuclear Information System (INIS)

    In this research thesis, the author reports the development of an ALGOL compiler which performs the main following tasks: systematic scan of the origin-programme to recognise the different components (identifiers, reserved words, constants, separators), analysis of the origin-programme structure to build up its statements and arithmetic expressions, processing of symbolic names (identifiers) to associate them with values they represent, and memory allocation for data and programme. Several issues are thus addressed: characteristics of the machine for which the compiler is developed, exact definition of the language (grammar, identifier and constant formation), syntax processing programme to provide the compiler with necessary elements (language vocabulary, precedence matrix), description of the first two phases of compilation: lexicographic analysis, and syntax analysis. The last phase (machine-code generation) is not addressed

  10. Algol: An Early Candidate for a Transiting Exoplanet

    Science.gov (United States)

    French, Linda M.; Stuart, I.

    2008-09-01

    Virtually every astronomy text credits John Goodricke (1764-1786) with the discovery of the period of variability of the star Algol (β Per) and with the explanation of its variation (eclipses by an unseen stellar companion). Today, Algol is considered a prototype of an eclipsing binary star. In actuality, John Goodricke worked in collaboration with his neighbor, mentor, and distant relative, Edward Pigott. As observed by Hoskin1, the observing journals2 of the two clearly show that the eclipse explanation originated with Edward. Both originally used the term "planet” to describe the eclipsing body. However, in Goodricke's 1783 paper describing Algol, he writes: "....I should imagine it could hardly be accounted for otherwise than either by the interposition of a large body revolving round Algol, or some kind of motion of its own, whereby part of its body, covered with spots or such like matter...."3 Goodricke was later to soften his stance still further after the two discovered several other variable stars; his last published work4 mentions only starspots as an explanation for the light variation of Algol. Although the physics of the time would not have allowed Goodricke and Pigott to distinguish between a star and a planet as the unseen companion, the eighteenth-century astronomers showed great prescience in realizing that the eclipses of Algol were just that. Their mental leap, at a time when astronomers were just beginning to think seriously of discovering planets around other stars, should not go unremembered by modern planetary scientists. Footnotes 1 Hoskin, M. (1982). In Stellar Astronomy, Science History Publications Ltd., Chalfont St. Giles, England. 2 Goodricke and Pigott journals. York City Archives, York, England. 3 Goodricke, J. G. (1783). Phil. Soc. Roy. Soc. London 73, 474-482. 4 Goodricke, J. G. (1786). Phil. Soc. Roy. Soc. London 76, 48-61.

  11. Numerical methods of mathematical optimization with Algol and Fortran programs

    CERN Document Server

    Künzi, Hans P; Zehnder, C A; Rheinboldt, Werner

    1971-01-01

    Numerical Methods of Mathematical Optimization: With ALGOL and FORTRAN Programs reviews the theory and the practical application of the numerical methods of mathematical optimization. An ALGOL and a FORTRAN program was developed for each one of the algorithms described in the theoretical section. This should result in easy access to the application of the different optimization methods.Comprised of four chapters, this volume begins with a discussion on the theory of linear and nonlinear optimization, with the main stress on an easily understood, mathematically precise presentation. In addition

  12. Search for systemic mass loss in Algols with bow shocks

    Science.gov (United States)

    Mayer, A.; Deschamps, R.; Jorissen, A.

    2016-03-01

    Aims: Various studies indicate that interacting binary stars of Algol type evolve non-conservatively. However, direct detections of systemic mass loss in Algols have been scarce so far. We study the systemic mass loss in Algols by looking for the presence of infrared excesses originating from the thermal emission of dust grains, which is linked to the presence of a stellar wind. Methods: In contrast to previous studies, we make use of the fact that stellar and interstellar material is piled up at the edge of the astrosphere where the stellar wind interacts with the interstellar medium. We analyse WISE W3 12 μm and WISE W4 22 μm data of Algol-type binary Be and B[e] stars and the properties of their bow shocks. From the stand-off distance of the bow shock we are able to determine the mass-loss rate of the binary system. Results: Although the velocities of the stars with respect to the interstellar medium are quite low, we find bow shocks present in two systems, namely π Aqr, and ϕ Per; a third system, CX Dra, shows a more irregular circumstellar environment morphology which might somehow be related to systemic mass loss. The properties of the two bow shocks point to mass-loss rates and wind velocities typical of single B stars, which do not support an enhanced systemic mass loss.

  13. A contribution to the solution of the Algol paradox

    International Nuclear Information System (INIS)

    The near infrared sensitivity of the Utrecht Stellar Photometer is advantageous in getting more information about secondaries of Algols. In this thesis, the evolution of these semidetached binary stars is studied. First, the Utrecht Photometric System (UPS) is tested on the, in principle, straightforward detached binary system YZ Cas, and UPS light curves of the Algol TV Cas are presented and interpreted. This partially eclipsing system (primary eclipse is an occultation) shows the typical Algol characteristics: the secondary fills its Roche Lobe and the period is variable. Next, IUE observations are used to determine some photospheric parameters of TV Cas and YZ Cas. TV Cas has a normal metal abundance and did not show evidence for mass motions at the time of observation. The known metal richness of YZ Cas was quantitatively estimated on the basis of line strengths. Being at this stage evolutionary model calculations are tested on YZ Cas. This system can be regarded as consisting of two single stars. Finally, the first quantitative deduction of the initial parameters of an Algol is presented: TV Cas consisted originally of a 3.0 plus a 2.4 solar masses component. (Auth.)

  14. An Observational Study of Algol-Type Binary System

    Science.gov (United States)

    Zhang, J.

    2015-01-01

    The Algol-Type binary systems are a subtype of binary systems. Their unique semi-detached structure leads to have abundant physical phenomena, including the dramatically distorted donor star, strong magnetic activities, various ways of mass transfer, the evolution stage quite different from that of single stars, and specific formation tracks. In this paper, we introduce the fundamental physics of light curves, as well as the models or programs used in the past. We show the influence of different parameters on the light curves, including the inclination, temperature, abundance, surface gravity, the third light, radius, orbital eccentricity, and the argument of periastron. Based on the current catalog of Algols, we investigate their statistic characteristics. We observe three Algols and analyze the data in detail. The results are as follows: (1)Our statistical analyses of Algols support the previous suggestion that most of the detached component stars are main sequence stars. The distribution of the mass ratio agrees to our calculated critical value of the mass ratio for Algols. We suggest that there could be a lower limit of the radius ratio. We also show that there are good correlations among the temperature, luminosity, radius, and the mass of the component stars. (2) The binary FG Gem is observed, and the data are analyzed. Based on the solutions of large combinations of the temperature and luminosity, we use a new age-comparing method to show that the FG Gem is a semi-detached system, and a new temperature-searching method to get a better estimate of the temperature of the detached component star. We suggest that a combination of the intermittent mass flow and the continuous magnetic braking can explain its orbital period change. (3) Taking the VV Vir as an example, we discuss some properties of the mass flow in a semi-detached binary. Some of them can reflect the common characteristics of the mass flows in the Algol systems, e.g., the radius of the mass flow is

  15. XMM-Newton observation of the eclipsing binary Algol

    Institute of Scientific and Technical Information of China (English)

    Xue-Juan Yang; Fang-Jun Lu; Bernd Aschenbach; Li Chen

    2011-01-01

    We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary.The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star.The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model.The cool component has a temperature around 6.4×106 K while that of the hot component ranges from 2 to 4.0× 107 K.Coronal abundances of C, N, O, Ne, Mg, Si and Fe were obtained for each component for both the quiescent and the flare phases, generally with upper limits for S and Ar, and upper limits for C, N, and O from the hot component.F-tests show that the abundances do not need to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of Fe.Although the Fe abundance of the cool component remains constant at ~0.14, the hot component shows an Fe abundance of ~0.28, which increases to ~0.44 during the flare.This increase is expected from the chromospheric evaporation model.The absorbing column density NH of the quiescent emission is 2.5 × 1020 cm-2, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium.This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.

  16. [Algolization of drinkable water basins in Nizhny Tagil industrial complex].

    Science.gov (United States)

    Kul'nev, V V; Pochechun, V A

    2016-01-01

    The article covers experience of biologic rehabilitation through correction of algocenosis (algolization) of drinkable water basins in Nizhny Tagil industrial complex. Biologic rehabilitation of Chernoistochnik and Verhne-Vyisky drinkable water basins in 2011-2012 considerably improved water quality in ecologic hydrochemical and hydrobiologic parameters--that was proved by absent water contamination with blue-green algae, lower saprobiont index. Results also are significant lower concentration of pollutants--heavy metals (ferrum, manganese, copper), oil products, decreased odor and and better water quality in hydrochemical parameters to second class according to water pollution index. PMID:27048137

  17. Doppler Shifts and Broadening and the Structure of the X-ray Emission from Algol

    CERN Document Server

    Chung, S M; Kashyap, V L; Lin, L W; Ratzlaff, P W; Chung, Sun Mi; Drake, Jeremy J.; Kashyap, Vinay L.; Lin, Li Wei; Ratzlaff, Peter W.

    2004-01-01

    In a study of Chandra High Energy Transmission Grating spectra of Algol, we clearly detect Doppler shifts caused by the orbital motion of Algol B. These data provide the first definitive proof that the X-ray emission of Algol is dominated by the secondary, in concordance with expectations that Algol A (B8) is X-ray dark. The measured Doppler shifts are slightly smaller than expected, implying an effective orbital radius of about 10 Rsolar, instead of 11.5 Rsolar for the Algol B center of mass. This could be caused by a small contribution of X-ray flux from Algol A (10-15%), possibly through accretion. The more likely explanation is an asymmetric corona biased toward the system center of mass by the tidal distortion of the surface of Algol B. Analysis of the strongest lines indicates excess line broadening of ~150 km/s above that expected from thermal motion and surface rotation. Possible explanations include turbulence, flows or explosive events, or rotational broadening from a radially extended corona. We fa...

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

    OpenAIRE

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

    2014-01-01

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

  19. Development of the Algol III solid rocket motor for SCOUT.

    Science.gov (United States)

    Felix, B. R.; Mcbride, N. M.

    1971-01-01

    The design and performance of a motor developed for the first stage of the NASA SCOUT-D and E launch vehicles are discussed. The motor delivers a 30% higher total impulse and a 35 to 45% higher payload mass capability than its predecessor, the Algol IIB. The motor is 45 in. in diameter, has a length-to-diameter ratio of 8:1 and delivers an average 100,000-lb thrust for an action time of 72 sec. The motor design features a very high volumetrically loaded internal-burning charge of 17% aluminized polybutadiene propellant, a plasma-welded and heat-treated steel alloy case, and an all-ablative plastic nose liner enclosed in a steel shell. The only significant development problem was the grain design tailoring to account for erosive burning effects which occurred in the high-subsonic-Mach-number port. The tests performed on the motor are described.

  20. [An algol program for the computation of empiric regressions].

    Science.gov (United States)

    Peil, J; Schmerling, S

    1977-01-01

    An explanation is given about the meaning of empirical regression and on the domain of application of this biomathematical-statistical procedure. It may be helpful in data handling after the measurements and in a first stage of data processing especially if there is a large amount of datas. An empirical regression can provide the basis for a functional relationship analysis by giving hints for the choice of empirical mathematical functions. This will be useful and necessary in such cases where the measured values have a greater dispersion and one wants to get an analytical expression for the course of measured points. In the appendix a program listing of the ALGOL-program for empirical regression is presented. Detailed remarks are made in the text concerning the program structure, the data input and output resp. the program control parameters to enable the biological or medical user to adapt the program to their special problems without the help by a mathematician, and neither with deeper knowledge of mathematics nor with detailed insight to computer technical aspects of data processing. PMID:590714

  1. Non-conservative evolution in Algols: where is the matter?

    CERN Document Server

    Deschamps, Romain; Jorissen, Alain; Siess, Lionel; Baes, Marteen; Camps, Peter

    2015-01-01

    There is gathering indirect evidence suggesting non-conservative evolutions in Algols. However, the systemic mass-loss rate is poorly constrained by observations and generally set as a free parameter in binary-star evolution simulations. Moreover, systemic mass loss may lead to observational signatures that are still to be found. We investigate the impact of the outflowing gas and the possible presence of dust grains on the spectral energy distribution (SED). We used the 1D plasma code Cloudy and compared the results with the 3D Monte-Carlo radiative transfer code Skirt for dusty simulations. The circumbinary mass-distribution and binary parameters are computed with state-of-the-art binary calculations done with the Binstar evolution code. The outflowing material reduces the continuum flux-level of the stellar SED in the optical and UV. Due to the time-dependence of this effect, it may help to distinguish between different ejection mechanisms. Dust, if present, leads to observable infrared excesses even with ...

  2. Spectroscopic Analysis of Oscillating Algol-Type Systems

    Science.gov (United States)

    Tkachenko, A.; Lehmann, H.; Tsymbal, V.; Mkrtichian, D.

    2010-12-01

    We analyze time-series of highresolution spectra of RZCas, one of the brightest Algoltype stars where the primary shows δ Sct-like oscillations. Our inverstigation uses a variety of methods like the KOREL program to derive the orbital solution and to decompose the spectra of the binary components, the SynthV program to derive the elemental abundances of both components from the mean, decomposed spectra, and finally the newly developed Shellspec07_inverse program to compute optimized stellar parameters from the composite line profiles observed at different orbital phases including the eclipse mapping. Spectra of RZ Cas have been taken at two different epochs. In 2006, the system can be well modeled without including any Algol-typical effects like a gas stream or an accretion annulus into the calculations. We have only to assume that the secondary of RZCas shows a large dark spot on its surface pointing toward the primary, presumably originating from a cooling mechanism by the enthalpy transport via the inner Lagrangian point. The O-C residuals of our solution based on the spectra from 2001 show a complex distribution of circumbinary matter, however, pointing to the occurrence of an episode of rapid mass transfer. This assumption is supported by the deduced change of the orbital period of RZCas of 2 seconds between the two epochs of observations. Numerical simulations of the spatial filtration effect that occures during the primary eclipse showed that this effect can be used for an identification of the excited non-radial pulsation modes in terms of l and m numbers.

  3. A search for systemic mass loss in Algols with bow shocks

    CERN Document Server

    Mayer, Andreas; Jorissen, Alain

    2016-01-01

    Aims. Various studies indicate that interacting binary stars of Algol type evolve non-conservatively. However, direct detection of systemic mass loss in Algols has been scarce so far. We aim at studying the systemic mass loss in Algols by looking for the presence of infrared excesses originating from the thermal emission of dust grains, which is linked to the presence of a stellar wind. Methods. In contrast to previous studies, we make use of the fact that stellar and interstellar material is piled up at the edge of the asterosphere where the stellar wind interacts with the interstellar medium. We analyse WISE W3 $12\\,\\mu$m and WISE W4 $22\\,\\mu$m data of Algol-type binary Be and B[e] stars and the properties of their bow shocks. From the stand-off distance of the bow shock we are able to determine the mass loss rate of the binary system. Results. Although the velocities of the stars with respect to the interstellar medium are quite low, we find bow shocks to be present in two systems, namely $\\pi$ Aqr, and $\\...

  4. Shifting Milestones of Natural Sciences: The Ancient Egyptian Discovery of Algol's Period Confirmed

    CERN Document Server

    Jetsu, Lauri

    2016-01-01

    The Ancient Egyptians wrote Calendars of Lucky and Unlucky Days that assigned astronomically influenced prognoses for each day of the year. The best preserved of these calendars is the Cairo Calendar (hereafter CC) dated to 1244--1163 B.C. We have presented evidence that the 2.85 days period in the lucky prognoses of CC is equal to that of the eclipsing binary Algol during this historical era. We wanted to find out the vocabulary that represents Algol in the mythological texts of CC. Here we show that Algol was represented as Horus and thus signified both divinity and kingship. The texts describing the actions of Horus are consistent with the course of events witnessed by any naked eye observer of Algol. These descriptions support our claim that CC is the oldest preserved historical document of the discovery of a variable star. The period of the Moon, 29.6 days, has also been discovered in CC. We show that the actions of Seth were connected to this period, which also strongly regulated the times described as ...

  5. A brief description and comparison of programming languages FORTRAN, ALGOL, COBOL, PL/1, and LISP 1.5 from a critical standpoint

    Science.gov (United States)

    Mathur, F. P.

    1972-01-01

    Several common higher level program languages are described. FORTRAN, ALGOL, COBOL, PL/1, and LISP 1.5 are summarized and compared. FORTRAN is the most widely used scientific programming language. ALGOL is a more powerful language for scientific programming. COBOL is used for most commercial programming applications. LISP 1.5 is primarily a list-processing language. PL/1 attempts to combine the desirable features of FORTRAN, ALGOL, and COBOL into a single language.

  6. Analysis of red and infrared wide-band photometry of Algol

    International Nuclear Information System (INIS)

    The basic physical picture of the Algol system is reviewed and, using collected red and infrared observations, photometric curve fits are investigated by applying numerical quadratures to determine theoretical light curves appropriate to Roche model stars. The 'contact' nature of Algol B appears to be confirmed, and effective temperatures of the three components are Tsub(A) = 11 4000, Tsub(B) = 53000, Tsub(C) = 76000. In terms of a Lambert's law approach to the 'reflection effect', the effective heat-albedo is required to be reduced from unity to one half; and it is also found that the averaged 'gravity-darkening coefficient' is close to a value appropriate for a diffusion type of heat-transfer mechanism operating in sub-photospheric layers. (Auth.)

  7. The low-mass classic Algol-type binary UU Leo revisited

    International Nuclear Information System (INIS)

    New multi-color photometry of the eclipsing binary UU Leo, acquired from 2010 to 2013, was carried out by using the 60-cm and 85-cm telescopes at the Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, the photometric solution was derived from BVR light curves. The results imply that UU Leo is a semi-detached Algol-type binary, with a mass ratio of q = 0.100(±0.002). The change in orbital period was reanalyzed based on all available eclipsing times. The O − C curve could be described by an upward parabola superimposed on a quasi-sinusoidal curve. The period and semi-amplitudes are Pmod = 54.5(±1.1) yr and A = 0.0273d(±0.0015d), which may be attributed to the light-time effect via the presence of an invisible third body. The long-term period increases at a rate of dP/dt = +4.64(±0.14) × 10−7d yr−1, which may be interpreted by the conserved mass being transferred from the secondary to the primary. With mass being transferred, the low-mass Algol-type binary UU Leo may evolve into a binary system with a main sequence star and a helium white dwarf

  8. Revision of the Phenomenological Characteristics of the Algol-Type Stars Using the NAV Algorithm

    CERN Document Server

    Tkachenko, Mariia G; Chinarova, Lidia L

    2015-01-01

    Phenomenological characteristics of the sample of the Algol-type stars are revised using a recently developed NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv 1212.6707A) and compared to that obtained using common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree (1994OAP.....7...49A, 2003ASPC..292..391A). The computer program NAV is introduced, which allows to determine the best fit with 7 "linear" and 5 "non-linear" parameters and their error estimates. The number of parameters is much smaller than for the TP fit (typically 20-40, depending on the width of the eclipse, and is much smaller (5-20) for the W UMa and beta Lyrae - type stars. This causes more smooth approximation taking into account the reflection and ellipsoidal effects (TP2) and generally different shapes of the primary and secondary eclipses. An application of the method to two-color CCD photometry to the recently discovered eclipsing...

  9. KIC 6220497: A New Algol-type Eclipsing Binary with Multiperiodic Pulsations

    Science.gov (United States)

    Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Koo, Jae-Rim

    2016-06-01

    We present both binarity and pulsation of KIC 6220497 from the Kepler observations. The light curve synthesis shows that the eclipsing system is a semi-detached Algol with parameters of q = 0.243±0.001, i = 77.3±0.3 deg, and ΔT = 3,372±58 K, in which the detached primary component fills its Roche lobe by ˜87%. A multiple frequency analysis of the eclipse-subtracted light residuals reveals 33 frequencies in the range of 0.75-20.22 d-1 with amplitudes between 0.27 and 4.56 mmag. Among these, four are pulsation frequencies in fundamental (f1, f5) and p (f2, f7) modes, and six are orbital frequency (f8, f31) and its harmonics (f6, f11, f20, f24), which can be attributed to tidally excited modes. For the pulsation frequencies, the pulsation constants of 0.16-0.33 d and the period ratios of Ppul/Porb = 0.042-0.089 indicate that the primary component is a δ Sct pulsating star and, thus, KIC 6220497 is an oscillating eclipsing Algol (oEA) star. The dominant pulsation period of 0.1174051±0.0000004 d is significantly longer than that expected from empirical relations that link the pulsation period with the orbital period. The surface gravity of log g1 = 3.78±0.03 is clearly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved EB, compared with normal oEA stars.

  10. KIC 6220497: a new Algol-type eclipsing binary with multiperiodic pulsations

    Science.gov (United States)

    Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Koo, Jae-Rim

    2016-08-01

    We present both binarity and pulsation of KIC 6220497 from the Kepler observations. The light curve synthesis shows that the eclipsing system is a semidetached Algol with parameters of q = 0.243 ± 0.001, i = 77.3 ± 0.3 deg, and ΔT = 3372 ± 58 K, in which the detached primary component fills its Roche lobe by ˜87 per cent. A multiple frequency analysis of the eclipse-subtracted light residuals reveals 33 frequencies in the range of 0.75-20.22 d-1 with amplitudes between 0.27 and 4.56 mmag. Among these, four are pulsation frequencies in fundamental (f1, f5) and p (f2, f7) modes, and six are orbital frequency (f8, f31) and its harmonics (f6, f11, f20, f24), which can be attributed to tidally excited modes. For the pulsation frequencies, the pulsation constants of 0.16-0.33 d and the period ratios of Ppul/Porb = 0.042-0.089 indicate that the primary component is a δ Sct pulsating star and, thus, KIC 6220497 is an oscillating eclipsing Algol (oEA) star. The dominant pulsation period of 0.117 4051 ± 0.000 0004 d is significantly longer than that expected from empirical relations that link the pulsation period with the orbital period. The surface gravity of log g1 = 3.78 ± 0.03 is clearly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved eclipsing binary, compared with normal oEA stars.

  11. KIC 6220497: A New Algol-type Eclipsing Binary with Multiperiodic Pulsations

    CERN Document Server

    Lee, Jae Woo; Kim, Seung-Lee; Koo, Jae-Rim

    2016-01-01

    We present both binarity and pulsation of KIC 6220497 from the {\\it Kepler} observations. The light curve synthesis shows that the eclipsing system is a semi-detached Algol with parameters of $q$ = 0.243$\\pm$0.001, $i$ = 77.3$\\pm$0.3 deg, and $\\Delta T$ = 3,372$\\pm$58 K, in which the detached primary component fills its Roche lobe by $\\sim$87\\%. A multiple frequency analysis of the eclipse-subtracted light residuals reveals 33 frequencies in the range of 0.75$-$20.22 d$^{-1}$ with amplitudes between 0.27 and 4.56 mmag. Among these, four are pulsation frequencies in fundamental ($f_1$, $f_5$) and $p$ ($f_2$, $f_7$) modes, and six are orbital frequency ($f_8$, $f_{31}$) and its harmonics ($f_6$, $f_{11}$, $f_{20}$, $f_{24}$), which can be attributed to tidally excited modes. For the pulsation frequencies, the pulsation constants of 0.16$-$0.33 d and the period ratios of $P_{\\rm pul}/P_{\\rm orb}$ = 0.042$-$0.089 indicate that the primary component is a $\\delta$ Sct pulsating star and, thus, KIC 6220497 is an osc...

  12. A survey study of energy distribution in component stars of Algol-type binary systems

    Science.gov (United States)

    Dobias, Jan Joseph

    A study survey of Algol-type binary systems was undertaken in order to investigate radiative flux distributions of their component stars. For hot primaries low-dispersion ultraviolet spectra, made with the International Ultraviolet Explorer (IUD) satellite, are combined at comparable phases with optical spectrophotometric scans, made at Lick Observatory, and then matched with a least-square method to Kurucz model atmospheres. Cooler secondaries are classified by matching their optical flux distributions, observed at totality, to standard stars. Results show that the U Sagittae system consists of a B7.5V-IV star while the secondary is matched by a G4III IV standard. The RW Tauri system consists of a B8V primary, while the secondary is matched by a KOIII standard. The UV spectrum of the primary in RY Geminorum matches that of an AOV standard. The secondary in RY GEM is KOIV. The system of RS Cephei consists of B9.7Ve and G8III-IV stars. The system of RW Persei consists of B9.6e and K2(+ or - 2)IV-III stars. The system of RX Geminorum consists of AOV or AOIII and K2(+ or - 2) stars. Finally, in Beta Lyrae the primary appears to be a B8.5-B9II-Ib object.

  13. Tracing CNO exposed layers in the Algol-type binary system u Her

    CERN Document Server

    Kolbas, V; Pavlovski, K; Southworth, J

    2014-01-01

    The chemical composition of stellar photospheres in mass-transferring binary systems is a precious diagnostic of the nucleosynthesis processes that occur deep within stars, and preserves information on the components history. The binary system u Her belongs to a group of hot Algols with both components being B-stars. We have isolated the individual spectra of the two components by the technique of spectral disentangling of a new series of 43 high-resolution echelle spectra. Augmenting these with an analysis of the Hipparcos photometry of the system yields revised stellar quantities for the components of u Her. For the primary component (the mass-gaining star) we find M_A = 7.88 +/- 0.26 M_sun, R_A = 4.93 +/- 0.15 R_sun and T_eff_A = 21600 +/- 220 K. For the secondary (the mass-losing star) we find M_B = 2.79 +/- 0.12 M_sun, R_B = 4.26 +/- 0.06 R_sun and T_eff_B = 12600 +/- 550 K. A non-LTE analysis of the primary star's atmosphere reveals deviations in the abundances of nitrogen and carbon from the standard c...

  14. An Algol Program for the Refinement of Nuclear and Magnetic Structures by the Profile Method. RCN Report

    International Nuclear Information System (INIS)

    A structure refinement method is described which does not use integrated neutron power intensities, single or overlapping, but employs directly the profile intensities obtained from stepscanning measurements of the power diagram. Nuclear as well as magnetic structures can be refined, the latter only when their magnetic unit cell is equal to or a multiple of the nuclear cell. The least squares refinement procedure allows, with a simple code, the introduction of linear or quadratic constraints between the parameters. The complete text of the Algol 60 program is given with a description of the format of the input tape. A test sample is included at the end of the report. (author)

  15. Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae

    CERN Document Server

    Miller, B; Richards, M; Koubsky, P; Peters, G J; Miller, Brendan; Budaj, Jan; Richards, Mercedes; Koubsky, Pavel; Peters, Geraldine J.

    2006-01-01

    We have developed a systematic procedure to study the disks in Algol-type binaries using spectroscopic analysis, synthetic spectra, and tomography. We analyzed 119 H-alpha spectra of TT Hya, an Algol-type eclipsing interacting binary, collected from 1985-2001. The new radial velocities enabled us to derive reliable orbital elements, including a small non-zero eccentricity, and to improve the accuracy of the absolute dimensions of the system. High resolution IUE spectra were also analyzed to study the formation of the ultraviolet lines and continuum. Synthetic spectra of the iron curtain using our new shellspec program enabled us to derive a characteristic disk temperature of 7000K. We have demonstrated that the UV emission lines seen during total primary eclipse cannot originate from the accretion disk, but most likely arise from a hotter disk-stream interaction region. The synthetic spectra of the stars, disk, and stream allowed us to derive a lower limit to the mass transfer rate of 2e-10 solar masses per y...

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

    Institute of Scientific and Technical Information of China (English)

    Jia Zhang; Sheng-Bang Qian; Boonrucksar Soonthornthum

    2009-01-01

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

  17. LUT Reveals an Algol-type Eclipsing Binary With Three Additional Stellar Companions in a Multiple System

    Science.gov (United States)

    Zhu, L.-Y.; Zhou, X.; Hu, J.-Y.; Qian, S.-B.; Li, L.-J.; Liao, W.-P.; Tian, X.-M.; Wang, Z.-H.

    2016-04-01

    A complete light curve of the neglected eclipsing binary Algol V548 Cygni in the UV band was obtained with the Lunar-based Ultraviolet Telescope in 2014 May. Photometric solutions are obtained using the Wilson–Devinney method. It is found that solutions with and without third light are quite different. The mass ratio without third light is determined to be q = 0.307, while that derived with third light is q = 0.606. It is shown that V548 Cygni is a semi-detached binary where the secondary component is filling the critical Roche lobe. An analysis of all available eclipse times suggests that there are three cyclic variations in the O–C diagram that are interpreted by the light travel-time effect via the presence of three additional stellar companions. This is in agreement with the presence of a large quantity of third light in the system. The masses of these companions are estimated as m sin i‧ ∼ 1.09, 0.20, and 0.52 M⊙. They are orbiting the central binary with orbital periods of about 5.5, 23.3, and 69.9 years, i.e., in 1:4:12 resonance orbit. Their orbital separations are about 4.5, 13.2, and 26.4 au, respectively. Our photometric solutions suggest that they contribute about 32.4% to the total light of the multiple system. No obvious long-term changes in the orbital period were found, indicating that the contributions of the mass transfer and the mass loss due to magnetic braking to the period variations are comparable. The detection of three possible additional stellar components orbiting a typical Algol in a multiple system make V548 Cygni a very interesting binary to study in the future.

  18. The quiescent and flaring EUV spectrum of Algol and its relationship to other active coronae. EUV spectroscopy of bright hyades coronae: 71 Tauri and Theta 1 Tauri

    Science.gov (United States)

    Stern, Robert A.

    1994-01-01

    This program involves analysis and interpretation of EUVE spectrometer observations of the active stars Algol (beta Per) and 71 Tauri. The EUVE satellite spectrometers observed the prototype eclipsing binary Algol over nearly 1.5 orbital periods. Effective exposure times were 100 ksec and 89 ksec in the short wave (70-180 A) and medium wave (140-370 A) channels. High temperature (up to 20 MK) Fe XVI-XXIV emission lines are clearly detected in the overall spectrum. In addition, a quiescent continuum is present which increases towards shorter wavelengths. Using synthesized spectra of optically thin line and continuum emission folded through the instrumental response, we have examined constraints on the (Fe/H) coronal abundance in Algol. We find that the coronal Fe is underabundant by factors that approximately equal 2-4 relative to solar photospheric values, unless an unreasonably large quantity of coronal plasma at T greater than 30 MK is present in the quiescent spectrum. The latter possibility is, however, inconsistent with available X-ray data. Lightcurves of the high temperature EUV lines compared to line emission at He II 304 A show considerable differences, with much deeper minima present in the He II line during both primary and secondary eclipses. Toward the end of the observation a moderate flare lasting approximately 6 hours was detected in the high temperature Fe emission lines. The 71 Tau observation, for about the same exposure time, revealed only a handful of weak emission lines; however, the strongest lines were also those of Fe XXIII/XX, suggesting a hot coronal plasma. No obvious flaring or other variation was present in the 71 Tau Deep Survey lightcurve.

  19. Lunar-based Ultraviolet Telescope study of the well-known Algol-type binary TW Dra

    Science.gov (United States)

    Liao, Wen-Ping; Qian, Sheng-Bang; Zejda, Miloslav; Zhu, Li-Ying; Li, Lin-Jia

    2016-06-01

    By using the Lunar-based Ultraviolet Telescope (LUT) from 2014 December 2 to December 4, the first near-UV light curve of the well-known Algol-type binary TW Dra is reported, which is analyzed with the 2013 version of the W-D code. Our solutions confirmed that TW Dra is a semi-detached binary system where the secondary component fills its Roche lobe. The mass ratio and a high inclination are obtained (q = 0.47, i = 86.68°). Based on 589 available data spanning more than one century, the complex period changes are studied. Secular increase and three cyclical changes are found in the corresponding orbital period analysis. The secular increase changes reveal mass transfer from the secondary component to the primary one at a rate of 6.8 × 10‑7 M ⊙ yr‑1. One large cyclical change of 116.04 yr may be caused by disturbance of visual component ADS 9706B orbiting TW Dra (ADS 9706A), while the other two cyclical changes with shorter periods of 22.47 and 37.27 yr can be explained as the result of two circumbinary companions that are orbiting around TW Dra, where the two companions are in simple 3 : 5 orbit-rotation resonances. TW Dra itself is a basic binary in a possible sextuple system with the configuration (1 + 1) + (1 + 1) + (1 + 1), which further suggests that multiplicity may be a fairly common phenomenon in close binary systems.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

  1. Photometric properties for selected algol-type binaries. VIII. The triple systems DI Peg and AF Gem revisited

    International Nuclear Information System (INIS)

    New extensive photometry for two triple binary stars, DI Peg and AF Gem, was performed from 2012 October to 2013 January, with two small telescopes at Xinglong station (XLs) of NAOC. From new multi-color observations and previously published ones in literature, the photometric models were (re)deduced using the updated Wilson-Devinney code. The results indicated that the low third lights exist in two classic Algol-type binaries, whose fill-out factors for the more massive components are fp = 78.2(± 0.4)% for DI Peg, and fp = 69.0(± 0.3)% for AF Gem, respectively. Through analyzing the O–C curves, the orbital periods for two binaries change in the complicated mode. The period of DI Peg possibly appears to show two light-time orbits, whose modulated periods are P 3 = 54.6(± 0.5) yr and P 4 = 23.0(± 0.6) yr, respectively. The inferred minimum masses for the inner and outer sub-stellar companions are M in = 0.095 M ☉ and M out = 0.170 M ☉, respectively. Therefore, DI Peg may be a quadruple star. The orbital period of AF Gem appears to show a continuous period decrease or a cyclic variation; the latter may be preferable. The cyclic oscillation, with a period of 120.3(± 2.5) yr, may be attributed to the light-time effect due to the third body. This kind of additional companion may extract angular momentum from the central system, which may play a key role in the evolution of the binary.

  2. First analysis of eight Algol-type binaries: EI Aur, XY Dra, BP Dra, DD Her, VX Lac, WX Lib, RZ Lyn, and TY Tri

    CERN Document Server

    Zasche, P

    2015-01-01

    The available photometry from the online databases were used for the first light curve analysis of eight eclipsing binary systems EI Aur, XY Dra, BP Dra, DD Her, VX Lac, WX Lib, RZ Lyn, and TY Tri. All these stars are of Algol-type, having the detached components and the orbital periods from 0.92 to 6.8 days. For the systems EI Aur and BP Dra the large amount of the third light was detected during the light curve solution. Moreover, 468 new times of minima for these binaries were derived, trying to identify the period variations. For the systems XY Dra and VX Lac the third bodies were detected with the periods 17.7, and 49.3 years, respectively.

  3. J Is for JavaScript: A Direct-Style Correspondence between Algol-Like Languages and JavaScript Using First-Class Continuations

    DEFF Research Database (Denmark)

    Danvy, Olivier; Shan, Chung-chieh; Zerny, Ian Steven

    2009-01-01

    It is a time-honored fashion to implement a domain-specific language (DSL) by translation to a general-purpose language. Such an implementation is more portable, but an unidiomatic translation jeopardizes performance because, in practice, language implementations favor the common cases. This...... tension arises especially when the domain calls for complex control structures. We illustrate this tension by revisiting Landin’s original correspondence between Algol and Church’s lambda-notation. We translate domain-specific programs with lexically scoped jumps to JavaScript. Our translation produces...... Steele. These two extreme translations require JavaScript implementations to cater either for first-class continuations, as Rhino does, or for proper tail recursion. Less extreme translations should emit more idiomatic control-flow instructions such as for, break, and throw. The present experiment leads...

  4. Coronal density diagnostics with Helium-like triplets CHANDRA--LETGS observations of Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099

    CERN Document Server

    Ness, J U; Burwitz, V; Mewe, R; Raassen, A J J; Van der Meer, R L J; Predehl, P; Brinkman, A C

    2002-01-01

    We present an analysis of ten cool stars (Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099) observed with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra X-ray Observatory. This sample contains all cools stars observed with the LETGS presently available to us with integration times sufficiently long to warrant a meaningful spectral analysis. Our sample comprises inactive, moderately active, and hyperactive stars and samples the bulk part of activity levels encountered in coronal X-ray sources. We use the LETGS spectra to carry out density and temperature diagnostics with an emphasis on the H-like and the He-like ions. We find a correlation between line flux ratios of the Lyman-Alpha and He-like resonance lines with the mean X-ray surface flux. We determine densities using the He-like triplets. For active stars we find no significant deviations from the low-density limit for the ions of Ne, Mg, and Si, while the measured line ratios for the i...

  5. Period Changes of the Algol System SZ Herculis

    Science.gov (United States)

    Lee, J. W.; Lee, C.-U.; Kim, S.-L.; Kim, H.-I.; Park, J.-H.; Hinse, T. C.

    2012-04-01

    New CCD photometric observations of SZ Her were obtained between February and May 2008. More than 1,100 times of minimum light spanning more than one century were used for the period analysis. We find that the orbital period of SZ Her has varied due to a combination of two periodic variations, with cycle lengths of P3 = 85.8 yr and P4 = 42.5 yr and semi-amplitudes of K3 = 0.013 days and K4 = 0.007 days, respectively. The most reasonable explanation for them is a pair of light-time-travel (LTT) effects driven by the existence of two M-type companions with minimum masses of M3 = 0.22 M⊙ and M4 = 0.19 M⊙, located at nearly 2:1 mean motion resonance. Then, SZ Her is a quadruple system and the 3rd and 4th components would stay in the stable orbital resonance.

  6. Phenomenological Modeling of the Light Curves of Algol-Type Eclipsing Binary Stars

    CERN Document Server

    Andronov, Ivan L

    2012-01-01

    We introduce a special class of functions for mathematical modeling of periodic signals of special shape with irregularly spaced arguments. This method was developed for determination of phenomenological characteristics of the light curves, which are necessary for registration in the "General Catalogue of Variable Stars" and other databases. For eclipsing binary stars with smooth light curves - of types EB and EW - it is recommended a trigonometric polynomial of optimal degree in a complete or symmetric form. For eclipsing binary systems with relatively narrow minima (EA-type), statistically optimal is an approximation of the light curves in a class of non-polynomial spline functions. It is used a combination of the second-order trigonometric polynomial (TP2, what describes effects of "reflection", "ellipsoidality" and "spotness") and localized contibutions of minima (parametrized in depth and profile separately for primary and secondary minima). Effectivity of the proposed method increases with decreasing ec...

  7. ANS spectrophotometry - Delta Pictoris as an upper-main-sequence algol system

    Science.gov (United States)

    Eaton, J. A.; Wu, C.-C.

    1983-01-01

    The early-type eclipsing binary Delta Pictoris has been studied with 260 observations in each of five UV bands. These are the most accurate observations to date, and no strong evidence for light-curve complications produced by circumstellar material has been found. Combined light curves from four epochs separated by intervals of six months do not show any strong dips or shoulders as seen in earlier investigations. The strength of th C IV wavelength 1550 line is independent of phase to better than 0.01 m. The root-mean-square scatterer shown by the light curves ranges from 0.006 m to 0.014 and may be evidence that either or both of the components are intrinsically variable. The integrated colors of the system are consistent with a B1 V spectral type and very little interstellar extinction. A detached solution of the light curves for a Roche model well with the spectroscopic mass ratio, but a semidetached solution cannot be ruled out.

  8. Continuous heating of a giant X-ray flare on Algol

    OpenAIRE

    Schmitt, J. H. M. M.; Favata, F.

    1999-01-01

    Giant flares can release large amounts of energy within a few days: X-ray emission alone can be up to ten percent of the star's bolometric luminosity. These flares exceed the luminosities of the largest solar flares by many orders of magnitude, which suggests that the underlying physical mechanisms supplying the energy are different from those on the Sun. Magnetic coupling between the components in a binary system or between a young star and an accretion disk has been proposed as a prerequisi...

  9. Photometric properties for selected Algol-type binaries. VI. The newly discovered oEA star FR Orionis

    International Nuclear Information System (INIS)

    New photometry of the neglected eclipsing binary FR Orionis was obtained in 2012 November and December. Using the updated Wilson-Devinney program, the photometric elements were deduced from two-color light curves. The results indicate that this system is a semi-detached binary, with a mass ratio of 0.325(± 0.002) and a fill-out factor of the primary of fp = 73.5(± 0.2)%. The oscillating light curves imply that FR Ori may be an oscillating EA (oEA)-type star with a rapidly pulsating, mass-accreting primary component. After we removed the theoretical light curves from the observations, Fourier analysis revealed that the more massive component possibly shows a δ Scuti type pulsation with four detected frequencies. The dominant frequency is f 1 = 38.6c day–1 (i.e., P puls = 37.3 minutes), and the pulsation constant is Q = 0.014 days. Based on all available eclipsing times, the orbital period is undergoing a secular period increase with a rate of dP/dt = +8.85(±0.66) × 10–8 day yr –1, which may be interpreted by mass transfer from the secondary to the primary. We expect that the more massive component will fill its Roche lobe due to mass transfer of the secondary. Therefore, the oEA star FR Ori may evolve into a contact configuration.

  10. Photometric properties for selected Algol-type binaries. VI. The newly discovered oEA star FR Orionis

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-01

    New photometry of the neglected eclipsing binary FR Orionis was obtained in 2012 November and December. Using the updated Wilson-Devinney program, the photometric elements were deduced from two-color light curves. The results indicate that this system is a semi-detached binary, with a mass ratio of 0.325(± 0.002) and a fill-out factor of the primary of f{sub p} = 73.5(± 0.2)%. The oscillating light curves imply that FR Ori may be an oscillating EA (oEA)-type star with a rapidly pulsating, mass-accreting primary component. After we removed the theoretical light curves from the observations, Fourier analysis revealed that the more massive component possibly shows a δ Scuti type pulsation with four detected frequencies. The dominant frequency is f {sub 1} = 38.6c day{sup –1} (i.e., P {sub puls} = 37.3 minutes), and the pulsation constant is Q = 0.014 days. Based on all available eclipsing times, the orbital period is undergoing a secular period increase with a rate of dP/dt = +8.85(±0.66) × 10{sup –8} day yr {sup –1}, which may be interpreted by mass transfer from the secondary to the primary. We expect that the more massive component will fill its Roche lobe due to mass transfer of the secondary. Therefore, the oEA star FR Ori may evolve into a contact configuration.

  11. Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae

    Czech Academy of Sciences Publication Activity Database

    Miller, B.; Budaj, J.; Richards, M.; Koubský, Pavel; Peters, G. J.

    Roč. 656, č. 2 ( 2007 ), s. 1075-1091. ISSN 0004-637X Institutional research plan: CEZ:AV0Z10030501 Keywords : TT Hya * accretion disks * spectroscopy * tomography Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.405, year: 2007

  12. On the design of two small batch operating systems 1965 - 1970

    OpenAIRE

    Kruseman Aretz, F.E.J.

    2013-01-01

    This paper describes the design considerations and decisions for two small batch operating systems, called MICRO and MILLI, for the Electrologica X8, a Dutch computer delivered from 1965 onwards. Their sole tasks were to run sequences of ALGOL 60 programs, thus transforming the X8 into an ALGOL 60 computer. They were developed in order to increase the efficient use of the hardware (MICRO) and to reduce waiting times for ALGOL 60 programs with small demands (MILLI). The work described here was...

  13. Annual review in automatic programming

    CERN Document Server

    Goodman, Richard

    2014-01-01

    Annual Review in Automatic Programming, Volume 4 is a collection of papers that deals with the GIER ALGOL compiler, a parameterized compiler based on mechanical linguistics, and the JOVIAL language. A couple of papers describes a commercial use of stacks, an IBM system, and what an ideal computer program support system should be. One paper reviews the system of compilation, the development of a more advanced language, programming techniques, machine independence, and program transfer to other machines. Another paper describes the ALGOL 60 system for the GIER machine including running ALGOL pro

  14. Aportación al conocimiento de las algas epicontinentales del S.E. de España. VI. Dinofíceas (Dinophyceae Fritsch. 1927) y Euglenofíceas (Euglenophyceae Schoenichem, 1925).

    OpenAIRE

    Aboal Sanjurjo, Marina

    1990-01-01

    En prospecciones algológicas realizadas durante los años 1982-85 por todo el sudeste español y en especial en la cuenca del Segura se han identificado 7 táxones de Dinofíceas y 15 de Euglenofíceas. 18 de ellas son novedad para la flora algológica del sudeste español y 3 para la flora española. Se reúnen en tablas los valores de los principales factores físicoquímicos del agua para cada especie

  15. John Goodricke, Edward Pigott, and Their Study of Variable Stars

    CERN Document Server

    French, L M

    2012-01-01

    John Goodricke and Edward Pigott, working in York, England, between 1781 and 1786, determined the periods of variation of eclipsing binaries such as Algol and Beta Lyrae and speculated that the eclipses of Algol might be caused by a "dark body," perhaps even a planet. They also determined the periods of variation of the first two known Cepheid variables, the stars whose period-luminosity relation today enables astronomers to determine distances to distant galaxies. Goodricke holds special interest because he was completely deaf and because he died at the age of 21. The lives and work of these two astronomers are described.

  16. Annual review in automatic programming

    CERN Document Server

    Goodman, Richard

    2014-01-01

    Annual Review in Automatic Programming focuses on the techniques of automatic programming used with digital computers. Topics covered range from the design of machine-independent programming languages to the use of recursive procedures in ALGOL 60. A multi-pass translation scheme for ALGOL 60 is described, along with some commercial source languages. The structure and use of the syntax-directed compiler is also considered.Comprised of 12 chapters, this volume begins with a discussion on the basic ideas involved in the description of a computing process as a program for a computer, expressed in

  17. Thunks and the λ-calculus

    DEFF Research Database (Denmark)

    Hatcliff, John; Danvy, Olivier

    Thirty-five years ago, thunks were used to simulate call-by-name under call-by-value in Algol 60. Twenty years ago, Plotkin presented continuation-based simulations of call-by-name under call-by-value and vice versa in the λ-calculus. We connect all three of these classical simulations by...

  18. Automatic plotting of pole figures on diffractometer DRON-1.5

    International Nuclear Information System (INIS)

    A scheme of electron control unit and construction of automatic attachment for studying texture are developed. An algorithm has been worked out, a program (ALGOL-60) has been designed and adjusted for calculation and construction of polar figures. Investigation has been carried out on textures of deformation in the Zr-2.5% Nb alloy

  19. Thunks and the λ-calculus

    DEFF Research Database (Denmark)

    Hatcliff, John; Danvy, Olivier

    1997-01-01

    Thirty-five years ago, thunks were used to simulate call-by-name under call-by-value in Algol 60. Twenty years ago, Plotkin presented continuation-based simulations of call-by-name under call-by-value and vice versa in the λ-calculus. We connect all three of these classical simulations by...

  20. Thunks and the λ-calculus

    DEFF Research Database (Denmark)

    Hatcliff, John; Danvy, Olivier

    1996-01-01

    Thirty-five years ago, thunks were used to simulate call-by-name under call-by-value in Algol 60. Twenty years ago, Plotkin presented continuation-based simulations of call-by-name under call-by-value and vice versa in the λ-calculus. We connect all three of these classical simulations by...

  1. The dance of the double stars

    International Nuclear Information System (INIS)

    The paper concerns pairs of stars orbiting one another. The evolutionary path model for close binary stars, involving a mass transfer of gases between the stars, is described. The life history of a single star; cataclysmic variables; the algol paradox, matter and lagranges' point; x-ray binaries and bursters; and pulsars; are all briefly discussed. (U.K.)

  2. A program for activation analysis data processing

    International Nuclear Information System (INIS)

    An ALGOL program for activation analysis data handling is presented. The program may be used either for single channel spectrometry data or for multichannel spectrometry. The calculation of instrumental error and of analysis standard deviation is carried out. The outliers are tested, and the regression line diagram with the related observations are plotted by the program. (author)

  3. Report IAU Comm. 42, Close Binary Stars

    OpenAIRE

    Ribas, Ignasi; Scarfe, Colin D.; Torres, Guillermo; Rucinski, Slavek M.; Sion, Edward M.; Richards, Mercedes T.; Niarchos, Panayiotis; Olah, Katalin

    2008-01-01

    Brief summaries are given about (1) close binary research from the perspective of the Bibliography of Close Binaries, (2) low-mass binaries and model discrepancies, (3) W UMa-type binaries, (4) cataclysmic variables, (5) Algol binaries, (6) the oEA stars, (7) effects of binarity on stellar activity.

  4. Recursive Programming: A Clarification

    NARCIS (Netherlands)

    Hove d'Ertsenryck, G.M.C. van den

    2012-01-01

    We show that the block concept, as it was introduced in ALGOL 60, and two of the three main techniques introduced by E. W. Dijkstra in his seminal article Recursive Programming to implement it, the so-called "static links" and "display", have been partly misunderstood. These misunderstandings may ha

  5. Dance of the double stars

    Energy Technology Data Exchange (ETDEWEB)

    Theokas, A.

    1985-09-19

    The paper concerns pairs of stars orbiting one another. The evolutionary path model for close binary stars, involving a mass transfer of gases between the stars, is described. The life history of a single star; cataclysmic variables; the algol paradox, matter and lagranges' point; x-ray binaries and bursters; and pulsars; are all briefly discussed.

  6. VARIABILITY SURVEY IN THE CoRoT SRa01 FIELD: IMPLICATIONS OF ECLIPSING BINARY DISTRIBUTION ON CLUSTER FORMATION IN NGC 2264

    Energy Technology Data Exchange (ETDEWEB)

    Klagyivik, P. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1121 Budapest XII, Konkoly Thege ut 15-17. (Hungary); Csizmadia, Sz.; Pasternacki, T.; Fruth, T.; Erikson, A.; Cabrera, J.; Eigmueller, P.; Kirste, S.; Rauer, H.; Titz-Weider, R. [Institut fuer Planetenforschung, Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstrasse 2, D-12489 Berlin (Germany); Chini, R.; Lemke, R. [Astronomisches Institut, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Kabath, P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago (Chile); Murphy, M. [Depto. Fisica, Universidad Catolica del Norte, PO 1280, Antofagasta (Chile)

    2013-08-10

    Time-series photometry of the CoRoT field SRa01 was carried out with the Berlin Exoplanet Search Telescope II in 2008/2009. A total of 1161 variable stars were detected, of which 241 were previously known and 920 are newly found. Several new, variable young stellar objects have been discovered. The study of the spatial distribution of eclipsing binaries revealed the higher relative frequency of Algols toward the center of the young open cluster NGC 2264. In general Algol frequency obeys an isotropic distribution of their angular momentum vectors, except inside the cluster, where a specific orientation of the inclinations is the case. We suggest that we see the orbital plane of the binaries almost edge-on.

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

    Institute of Scientific and Technical Information of China (English)

    Lin-Sen Li

    2012-01-01

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

  8. Ultraviolet, optical, infrared, and microwave observations of HR 5110

    Science.gov (United States)

    Little-Marenin, I. R.; Simon, T.; Ayres, T. R.; Cohen, N. L.; Feldman, P. A.

    1986-01-01

    Near-IR JHKLM photometric data and VLBI and IUE radio burst data collected on the short-period spectroscopic binary HR 5110 are analyzed to classify the object. The observed broadband colors were indicative of an F2 IV primary and a spotted K0 IV secondary. The system is being viewed pole-on, so is observable in the UV since the K companion has filled its Roche lobe. In comparisons of such features of Algol and RS VCn stars as the mass ratio, orbital inclination, presence or absence of evidence for mass streams, accretion disks, and active regions, spectral signatures, etc., sufficient similarities are found to classify HR 5110 as an Algol system.

  9. Abstraction Mechanisms in the BETA Programming Language

    DEFF Research Database (Denmark)

    Kristensen, Bent Bruun; Madsen, Ole Lehrmann; Møller-Pedersen, Birger;

    1983-01-01

    The BETA programming language is developed as part of the BETA project. The purpose of this project is to develop concepts, constructs and tools in the field of programming and programming languages. BETA has been developed from 1975 on and the various stages of the language are documented in [BETA...... a]. The application area of BETA is programming of embedded as well as distributed computing systems. For this reason a major goal has been to develop constructs that may be efficiently implemented. Furthermore the BETA language is intended to have a few number of basic but general constructs...... to SMALLTALK, BETA is a language in the ALGOL 60 ([ALGOL]) family. SIMULA 67 is a system description and a programming language. The DELTA language ([DELTA]) is a system description language only, allowing description of full concurrency, continuous change and component interaction, developed from a SIMULA...

  10. On a programming language for graph algorithms

    Science.gov (United States)

    Rheinboldt, W. C.; Basili, V. R.; Mesztenyi, C. K.

    1971-01-01

    An algorithmic language, GRAAL, is presented for describing and implementing graph algorithms of the type primarily arising in applications. The language is based on a set algebraic model of graph theory which defines the graph structure in terms of morphisms between certain set algebraic structures over the node set and arc set. GRAAL is modular in the sense that the user specifies which of these mappings are available with any graph. This allows flexibility in the selection of the storage representation for different graph structures. In line with its set theoretic foundation, the language introduces sets as a basic data type and provides for the efficient execution of all set and graph operators. At present, GRAAL is defined as an extension of ALGOL 60 (revised) and its formal description is given as a supplement to the syntactic and semantic definition of ALGOL. Several typical graph algorithms are written in GRAAL to illustrate various features of the language and to show its applicability.

  11. Algorithms over partially ordered sets

    DEFF Research Database (Denmark)

    Baer, Robert M.; Østerby, Ole

    1969-01-01

    partially ordered sets, answer the combinatorial question of how many maximal chains might exist in a partially ordered set withn elements, and we give an algorithm for enumerating all maximal chains. We give (in § 3) algorithms which decide whether a partially ordered set is a (lower or upper) semi......-lattice, and whether a lattice has distributive, modular, and Boolean properties. Finally (in § 4) we give Algol realizations of the various algorithms....

  12. The finite-difference neutron-diffusion programme TWODIM

    International Nuclear Information System (INIS)

    A description of the B 6700 Algol version of the two-dimensional neutron-diffusion programme TWODIM is given. The interative scheme used in TWODIM for solution of the eigenvalueproblems is the so-called Equipuise - or neutron-balance method, based on the SLOR-splitting. The Equipoise-scheme has been compared to DC3 and DC4 schemes. A sample problem is given. (author)

  13. Spiral Waves in Accretion Disks

    Science.gov (United States)

    Harlaftis, Emilios

    A review with the most characteristic spiral waves in accretion disks of cataclysmic variables will be presented. Recent work on experiments targeting the detection of spiral waves from time lapse movies of real disks and the study of permanent spiral waves will be discussed. The relevance of spiral waves with other systems such as star-planet X-ray binaries and Algols will be reviewed.

  14. Annual review in automatic programming

    CERN Document Server

    Halpern, Mark I; Bolliet, Louis

    2014-01-01

    Computer Science and Technology and their Application is an eight-chapter book that first presents a tutorial on database organization. Subsequent chapters describe the general concepts of Simula 67 programming language; incremental compilation and conversational interpretation; dynamic syntax; the ALGOL 68. Other chapters discuss the general purpose conversational system for graphical programming and automatic theorem proving based on resolution. A survey of extensible programming language is also shown.

  15. LISP software generative compilation within the frame of a SLIP system

    International Nuclear Information System (INIS)

    After having outlined the limitations associated with the use of some programming languages (Fortran, Algol, assembler, and so on), and the interest of the use of the LISP structure and its associated language, the author notices that some problems remain regarding the memorisation of the computing process obtained by interpretation. Thus, he introduces a generative compiler which produces an executable programme, and which is written in a language very close to the used machine language, i.e. the FAP assembler language

  16. Computer-aided determinatio of absorption cross section of multicomponent alloys

    International Nuclear Information System (INIS)

    For U alloys with Cu, Mo and Hf, the results are given of computer calculations of changes in the effective absorption cross section for thermal neutrons with composition of the alloys. The program was written in Algol 68 for the TESLA 200 computer. The program may be used for calculating the effective absorption cross section of any alloy consisting of a maximum of 6 components. (E.S.)

  17. The oEA star TW Dra - a spectroscopic analysis

    OpenAIRE

    Lehmann, H.; Tkachenko, A.; Tsymbal, V.; Mkrtichian, D. E.

    2008-01-01

    We investigate a spectroscopic time series of the oscillating Algol-type star TW Dra to derive basic system and stellar parameters and to prepare for mode identification. From the orbital solution we derive precise masses and get disentangled spectra of the components by using KOREL. For the primary we derive about solar abundance. Computed LSD profiles show a puzzling picture of blue-to-red traveling bumps indicating a rich spectrum of nonradial pulsations. Three pulsation frequencies could ...

  18. Time-series spectroscopy of the pulsating eclipsing binary XX Cephei

    OpenAIRE

    Koo, Jae-Rim; Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Lee, Chung-Uk

    2016-01-01

    Oscillating Algol-type eclipsing binaries (oEA) are very interesting objects that have three observational features of eclipse, pulsation, and mass transfer. Direct measurement of their masses and radii from the double-lined radial velocity data and photometric light curves would be the most essential for understanding their evolutionary process and for performing the asteroseismological study. We present the physical properties of the oEA star XX Cep from high-resolution time-series spectros...

  19. Indirect imaging of an accretion disk rim in the long-period interacting binary W Crucis

    CERN Document Server

    Pavlovski, K; Mimica, P

    2006-01-01

    Light curves of the long-period Algols are known for their complex shape (asymmetry in the eclipse, light variations outside eclipse, changes from cycle-to-cycle), and their interpretation is not possible in the standard model of binary stars. Complex structures present in these active Algol systems could be studied with the eclipse-mapping method which was successfully applied to the new 7-color photometric observations in the Geneva system of W Cru, belonging to the isolated group of these active Algols. Several cycles of this long-period (198.5 days) eclipsing binary have been covered by observations. We have used a modified Rutten's approach to the eclipse-mapping. The optimization of the system's parameters and the recovery of the disk intensity distribution are performed using a genetic algorithm (GA). It is found that a hot component is hidden in the thick accretion disk which confirms previous findings. The mass of the component, M1 = 8.2 Ms indicates that it is a mid-B type star. The mass-losing comp...

  20. The Risoe model for calculating the consequences of the release of radioactive material to the atmosphere

    International Nuclear Information System (INIS)

    A brief description is given of the model used at Risoe for calculating the consequences of releases of radioactive material to the atmosphere. The model is based on the Gaussian plume model, and it provides possibilities for calculation of: doses to individuals, collective doses, contamination of the ground, probability distribution of doses, and the consequences of doses for give dose-risk relationships. The model is implemented as a computer program PLUCON2, written in ALGOL for the Burroughs B6700 computer at Risoe. A short description of PLUCON2 is given. (author)

  1. SCOUT Nozzle Data Book

    Science.gov (United States)

    Shieds, S.

    1976-01-01

    Available analyses and material property information are summarized relevant to the design of four rocket motor nozzles currently incorporated in the four solid propellant rocket stages of the NASA SCOUT launch vehicle. The nozzles discussed include those for the following motors: (1) first stage - Algol IIIA; (2) second stage - Castor IIA; (3) third stage - Antares IIA; and (4) fourth stage - Altair IIIA. Separate sections for each nozzle provide complete data packages. Information on the Antares IIB motor which had limited usage as an alternate motor for the third stage is included.

  2. Dust Around Herbig Ae Stars: Additional Constraints from their Photometric and Polarimetric Variability

    Science.gov (United States)

    Krivova, N. A.; Ilin, V. B.; Fischer, O.

    1996-01-01

    For the Herbig Ae stars with Algol-like minima (UX Ori, WW Vul, etc), the effects of circumstellar dust include: excess infrared emission, anomalous ultraviolet extinction, the 'blueing' of the stars in minima accompanying by an increase of intrinsic polarization. Using a Monte-Carlo code for polarized radiation transfer we have simulated these effects and compared the results obtained for different models with the observational data available. We found that the photometric and polarimetric behavior of the stars provided essential additional constraints on the circumstellar dust models. The models with spheroidal shell geometry and compact (non-fluffy) dust grains do not appear to be able to explain all the data.

  3. Introducción a C y a métodos numéricos

    OpenAIRE

    Mora Escobar, Héctor Manuel

    2004-01-01

    El lenguaje de programación más utilizado para cálculos científicos es el Fortran, bien sea en sus versiones originales, en Fortran-77 o en Fortran-90. Inicialmente Fortran fue el único lenguaje empleado para cálculo científico. Posteriormente se utilizaron también otros lenguajes, como Algol, PL-1, Pascal, C, C++… Actualmente se sigue utilizando ampliamente Fortran en laboratorios de investigación del más alto nivel pues, además de sus buenas cualidades hay muchos programas y bibliotecas ...

  4. Pulsating Components in Binary and Multiple Stellar Systems --- A Catalog of Oscillating Binaries

    OpenAIRE

    Zhou, A. -Y.

    2010-01-01

    We present an up-to-date catalog of pulsating binaries, i.e. the binary and multiple stellar systems containing pulsating components, along with a statistics on them. Compared to the earlier compilation by Soydugan et al.(2006a) of 25 delta Scuti-type `oscillating Algol-type eclipsing binaries' (oEA), the recent collection of 74 oEA by Liakos et al.(2012), and the collection of Cepheids in binaries by Szabados (2003a), the numbers and types of pulsating variables in binaries are now extended....

  5. Quantitative spectroscopy of close binary stars

    CERN Document Server

    Pavlovski, K

    2011-01-01

    The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect in understanding the evolution of stellar systems. We review different ways to reconstruct individual spectra from eclipsing and non-eclipsing systems, and then concentrate on some recent applications to detached binaries with high-mass and intermediate-mass stars, and Algol-type mass-transfer systems.

  6. A Multiwavelength Study of RZ Cassiopeiae: The XMM-Newton/VLA Campaign

    OpenAIRE

    Audard, Marc; Donisan, Julius R.; Guedel, Manuel

    2004-01-01

    XMM-Newton and the VLA simultaneously observed the eclipsing Algol-type binary RZ Cassiopeiae in August 2003. The secondary eclipse (K3 IV companion behind the A3 V primary) was placed at the center of the 15-hour radio campaign, while the X-ray satellite monitored a full 1.2-day orbital period. We present results of the X-ray and radio campaigns. The X-ray light curve shows significant modulation probably related to rotational modulation and active region evolution, and even small flares. Ho...

  7. Program verification using symbolic game semantics

    DEFF Research Database (Denmark)

    Dimovski, Aleksandar

    2014-01-01

    We introduce a new symbolic representation of algorithmic game semantics, and show how it can be applied for efficient verification of open (incomplete) programs. The focus is on an Algol-like programming language which contains the core ingredients of imperative and functional languages, especia......We introduce a new symbolic representation of algorithmic game semantics, and show how it can be applied for efficient verification of open (incomplete) programs. The focus is on an Algol-like programming language which contains the core ingredients of imperative and functional languages......, especially on its second-order recursion-free fragment with infinite data types. We revisit the regular-language representation of game semantics of this language fragment. By using symbolic values instead of concrete ones, we generalize the standard notions of regular-language and automata representations...... of game semantics to that of corresponding symbolic representations. In this way programs with infinite data types, such as integers, can be expressed as finite-state symbolic-automata although the standard automata representation is infinite-state, i.e. the standard regular-language representation...

  8. Newly Discovered Eclipsing Binary 2MASS J18024395+4003309 (VSX J180243.9+400331):Two-Color Photometry vs Phenomenological Modeling

    CERN Document Server

    Andronov, Ivan L; Kim, Young-Hee; Yoon, Joh-Na; Chinarova, Lidia L; Tkachenko, Mariia G

    2015-01-01

    We report on analysis of the two-color VR CCD observations of the newly discovered variable 2MASS J18024395+4003309=VSX J180243.9+400331 obtained using the 1-m telescope of the Mt. Lemmon Observatory (LOAO) in the field of the intermediate polar V1323 Her. The extended version of this conference talk we published in 2015JASS...32..127A. The variability was reported in 2012OAP....25..150A, and the object was monitored. The two-color observations covered all phase interval. The object is classified as an Algol-type variable with tidally distorted components, and shows an asymmetry of the maxima (the O\\'Connell effect). For phenomenological modeling, we used the trigonometric polynomial approximation of statistically optimal degree, and a recent method "NAV" (New Algol Variable) using local specific shapes for the eclipse. Methodological aspects are described, especially for the case of few color observations. Estimates of the physical parameters based on analysis of phenomenological parameters, are presented.

  9. Phemenological Modelling of a Group of Eclipsing Binary Stars

    CERN Document Server

    Andronov, Ivan L; Chinarova, Lidia L

    2015-01-01

    Phenomenological modeling of variable stars allows determination of a set of the parameters, which are needed for classification in the "General Catalogue of Variable Stars" and similar catalogs. We apply a recent method NAV ("New Algol Variable") to eclipsing binary stars of different types. Although all periodic functions may be represented as Fourier series with an infinite number of coefficients, this is impossible for a finite number of the observations. Thus one may use a restricted Fourier series, i.e. a trigonometric polynomial (TP) of order s either for fitting the light curve, or to make a periodogram analysis. However, the number of parameters needed drastically increases with decreasing width of minimum. In the NAV algorithm, the special shape of minimum is used, so the number of parameters is limited to 10 (if the period and initial epoch are fixed) or 12 (not fixed). We illustrate the NAV method by application to a recently discovered Algol-type eclipsing variable 2MASS J11080308-6145589 (in the...

  10. The SINTRAN III NODAL system

    International Nuclear Information System (INIS)

    NODAL is a high level programming language based on FOCAL and SNOBOL4, with some influence from BASIC. The language was developed to operate on the computer network controlling the SPS accelerator at CERN. NODAL is an interpretive language designed for interactive use. This is the most important aspect of the language, and is reflected in its structure. The interactive facilities make it possible to write, debug and modify programs much faster than with compiler based languages like FORTRAN and ALGOL. Apart from a few minor modifications, the basic part of the Oslo University NODAL system does not differ from the CERN version. However, the Oslo University implementation has been expanded with new functions which enable the user to execute many of the SINTRAN III monitor calls from the NODAL level. In particular the most important RT monitor calls have been implemented in this way, a property which renders possible the use of NODAL as a RT program administrator. (JIW)

  11. Data Mining Analysis for Eclipsing Binary TrES-Cyg3-04450

    Science.gov (United States)

    Hinzel, D. H.

    2015-12-01

    A data mining algorithm was utilized to analyze Johnson V-band charge-coupled device (CCD) photometric data of an object that were taken during a wide field survey of a region in the constellation Cygnus. That algorithm was the Date Compensated Discrete Fourier Transform (DC DFT) which is part of the AAVSO VSTAR applications software. This analysis clearly indicated that the object under study is a detached eclipsing binary, specifically an EA β Persei-type (Algol) eclipsing system, with an orbital period of 2.0664 days. Neither the type nor period of this eclipsing binary had been characterized up to this point. This object has been given the AAVSO designation TrES-Cyg3-04450 and the AUID 000-BLL-484.

  12. Analysis of the eclipsing binary ST Carinae using the SIMPLEX algorithm

    International Nuclear Information System (INIS)

    This work presents the analyses of two UBV data sets for the Algol binary ST Carinae, presenting a homogeneous study of all the data. The light-curve parameters for the system are derived using the Wilson-Devinney model (1917), with the SIMPLEX algorithm as an optimization procedure, and a mass ratio of q=0.54 is obtained. The primary has colors consistent with a B9.5 V primary, and the solution indicates that the secondary is an F subgiant (Te=6200 K) that fills its Roche lobe. The application of Kepler's law (using the observed period and the mass ratio determined in this investigation) indicates that the absolute dimensions for the components are normal for their respective classes. A description of SIMPLEX is given, and its advantages for the solution of eclipsing binary parameters are discussed. 19 refs

  13. NSV 1907 - A new eclipsing, nova-like cataclysmic variable

    CERN Document Server

    Hümmerich, Stefan; Hambsch, Franz-Josef; Dubois, Franky; Ashley, Richard; Gänsicke, Boris T; Vanaverbeke, Siegfried; Bernhard, Klaus; Wils, Patrick

    2016-01-01

    NSV 1907, formerly listed as an irregular variable in variability catalogues, was classified as an Algol-type eclipsing binary in the Catalina Surveys Periodic Variable Star Catalogue. We have identified NSV 1907 as an ultraviolet (UV) bright source using measurements from the GALEX space telescope and detected obvious out-of-eclipse variability in archival photometric data from the Catalina Sky Survey, which instigated a closer examination of the object. A spectrum and extensive multicolour photometric observations were acquired, from which we deduce that NSV 1907 is a deeply eclipsing, nova-like cataclysmic variable. Apart from the orbital variations (deep eclipses with a period of P ~ 6.63 hours), changes in mean brightness and irregular short-term variability (flickering) were observed. The presence of a secondary minimum at phase phi ~ 0.5 was established, which indicates a significant contribution of the companion star to the optical flux of the system. We find possible evidence for sinusoidal variation...

  14. Two-dimensional multigroup finite element calculation of fast reactor in diffusion approximation

    International Nuclear Information System (INIS)

    When a linear element of triangular shape is used the actual finite element calculation is relatively simple. Extensive programs for mesh generation were written for easy inputting the configuration of reactors. A number of other programs were written for plotting neutron flux fields in individual groups, the power distribution, spatial plotting of fields, etc. The operation of selected programs, data preparation and operating instructions are described and examples given of data and results. All programs are written in GIER ALGOL. The used method and the developed programs have demonstrated that they are a useful instrument for the calculation of criticality and the distribution of neutron flux and power of both fast and thermal reactors. (J.B.)

  15. Photometric and spectroscopic investigation of TW Draconis

    CERN Document Server

    Zejda, M; Harmanec, P; Slechta, M; Mikulasek, Z; Zverko, J; Svoboda, P; Krticka, J

    2010-01-01

    Context. TW Draconis is one of the best studied Algol-type eclipsing binaries. There is significant evidence for miscellaneous physical processes between interacting binary components manifesting themselves by period and light curve changes. Aims. Obtaining new set of photometric and spectroscopic observations, we analysed them together with the older spectroscopic and photometric data to build model of this eclipsing system with respect to observed changes of O-C diagram and light curve. Methods. Reduction of new spectra was carried out in the IRAF and SPEFO programs. Radial velocities were determined manually using SPEFO, by CCF using the Zverko's code and from the program KOREL. Orbital elements were derived with the FOTEL program and via disentangling with KOREL. The final combined solution was obtained with the programs PHOEBE and FOTEL. Results. Photometry shows small irregularities in light curves as a results of pulsating of one component and spot activity. Using net of KOREL outputs we found the mass...

  16. A numerical library in Java for scientists and engineers

    CERN Document Server

    Lau, Hang T

    2003-01-01

    At last researchers have an inexpensive library of Java-based numeric procedures for use in scientific computation. The first and only book of its kind, A Numeric Library in Java for Scientists and Engineers is a translation into Java of the library NUMAL (NUMerical procedures in ALgol 60). This groundbreaking text presents procedural descriptions for linear algebra, ordinary and partial differential equations, optimization, parameter estimation, mathematical physics, and other tools that are indispensable to any dynamic research group. The book offers test programs that allow researchers to execute the examples provided; users are free to construct their own tests and apply the numeric procedures to them in order to observe a successful computation or simulate failure. The entry for each procedure is logically presented, with name, usage parameters, and Java code included. This handbook serves as a powerful research tool, enabling the performance of critical computations in Java. It stands as a cost-effi...

  17. BVR{sub c}I{sub c} OBSERVATIONS AND ANALYSES OF THE DWARF DETACHED BINARY V1043 CASSIOPEIA AND A COMMENT ON PRECONTACT W UMa'S

    Energy Technology Data Exchange (ETDEWEB)

    Samec, R. G.; Smith, P. M.; Chamberlain, H. [Astronomy Group, Physics and Engineering Department, Bob Jones University, 1700 Wade Hampton Boulevard, Greenville, SC 29614 (United States); Faulkner, D. R. [Division of Math, Science, Nursing and Public Health, University of South Carolina, Lancaster, 476 Hubbard Drive, Lancaster, SC 29720 (United States); Van Hamme, W. [Physics Department, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States)

    2013-01-01

    Complete Bessel BVR{sub c}I{sub c} light curves of V1043 Cassiopeia [2MASS J00371195+5301324, Mis V1292, USNO-A2.0 1425-00875743, {alpha}(2000) = 00{sup h}37{sup m}11.{sup s}95, {delta}(2000) = +53 Degree-Sign 01'32.''5] are analyzed. The system is a member of the small group of pre-contact W UMa binaries (PCWBs). Its light curve has the appearance of an Algol (EA) light curve, however it is made up of dwarf solar type components in a detached mode with a period of only 0.6616 days. The analysis includes a period study, an improved ephemeris, a mass ratio search, and a simultaneous BVR{sub c}I{sub c} Wilson-Devinney solution. We document about 20 other PCWBs given in the literature. Several have RS CVn-like properties.

  18. Development and evaluation of a Fault-Tolerant Multiprocessor (FTMP) computer. Volume 2: FTMP software

    Science.gov (United States)

    Lala, J. H.; Smith, T. B., III

    1983-01-01

    The software developed for the Fault-Tolerant Multiprocessor (FTMP) is described. The FTMP executive is a timer-interrupt driven dispatcher that schedules iterative tasks which run at 3.125, 12.5, and 25 Hz. Major tasks which run under the executive include system configuration control, flight control, and display. The flight control task includes autopilot and autoland functions for a jet transport aircraft. System Displays include status displays of all hardware elements (processors, memories, I/O ports, buses), failure log displays showing transient and hard faults, and an autopilot display. All software is in a higher order language (AED, an ALGOL derivative). The executive is a fully distributed general purpose executive which automatically balances the load among available processor triads. Provisions for graceful performance degradation under processing overload are an integral part of the scheduling algorithms.

  19. Aspects of FORTRAN in large-scale programming

    International Nuclear Information System (INIS)

    In these two lectures I examine the following three questions: i) Why did high-energy physicists begin to use FORTRAN. ii) Why do high-energy physicists continue to use FORTRAN. iii) Will high-energy physicists always use FORTRAN. In order to find answers to these questions, it is necessary to look at the history of the language, its present position, and its likely future, and also to consider its manner of use, the topic of portability, and the competition from other languages. Here we think especially of early competition from ALGOL, the more recent spread in the use of PASCAL, and the appearance of a completely new and ambitious language, ADA. (orig.)

  20. The Multiperiodic Pulsating Star Y Cam A as a Musical Instrument

    CERN Document Server

    Ulas, Burak

    2015-01-01

    In this study we generate musical chords from the oscillation frequencies of the primary component of oscillating eclipsing Algol system Y Cam. The parameters and the procedure of the musical chord generation process from the stellar oscillations are described in detail. A musical piece is also composed in appropriate scale for Y Cam A by using the generated chords from the results of the asteroseismic analysis of the stellar data. The music scores and the digital sound files are provided for both the generated chords and the musical composition. Our study shows that the further orchestral compositions can be made from the frequency analysis results of several pulsating stars by using the procedure stated in present study.

  1. RX Geminorum: Photometric Solutions, (Nearly Uniform) Gainer Rotation, Donor Radial Velocity Solution, Non-LTE Accretion Disk Models of Hα Emission Profiles, and Secular Light Curve Changes in the 20th Century

    Science.gov (United States)

    Olson, Edward C.; Etzel, Paul B.

    2015-04-01

    We obtained full-orbit Iybvu intermediate-band photometry and CCD spectroscopy of the long-period Algol eclipsing binary RX Geminorum. Photometric solutions using the Wilson-Devinney code give a gainer rotation (hotter, mass-accreting component) about 15 times the synchronous rate. We describe a simple technique to detect departures from uniform rotation of the hotter component. These binaries radiate double-peaked Hα emission from a low-mass accretion disk around the gainer. We used an approximate non-LTE disk code to predict models in fair agreement with observations, except in the far wings of the emission profile, where the star-inner disk boundary layer emits extra radiation. Variations in Hα emission derive from modulations in the transfer rate. A study of times of minima during the 20th century suggests that a perturbing third body is present near RX Gem.

  2. A Task-driven Grammar Refactoring Algorithm

    Directory of Open Access Journals (Sweden)

    Ivan Halupka

    2012-01-01

    Full Text Available This paper presents our proposal and the implementation of an algorithm for automated refactoring of context-free grammars. Rather than operating under some domain-specific task, in our approach refactoring is perfomed on the basis of a refactoring task defined by its user. The algorithm and the corresponding refactoring system are called mARTINICA. mARTINICA is able to refactor grammars of arbitrary size and structural complexity. However, the computation time needed to perform a refactoring task with the desired outcome is highly dependent on the size of the grammar. Until now, we have successfully performed refactoring tasks on small and medium-size grammars of Pascal-like languages and parts of the Algol-60 programming language grammar. This paper also briefly introduces the reader to processes occurring in grammar refactoring, a method for describing desired properties that a refactored grammar should fulfill, and there is a discussion of the overall significance of grammar refactoring.

  3. Statistically Optimal Approximations of Astronomical Signals: Implications to Classification and Advanced Study of Variable Stars

    Science.gov (United States)

    Andronov, I. L.; Chinarova, L. L.; Kudashkina, L. S.; Marsakova, V. I.; Tkachenko, M. G.

    2016-06-01

    We have elaborated a set of new algorithms and programs for advanced time series analysis of (generally) multi-component multi-channel observations with irregularly spaced times of observations, which is a common case for large photometric surveys. Previous self-review on these methods for periodogram, scalegram, wavelet, autocorrelation analysis as well as on "running" or "sub-interval" local approximations were self-reviewed in (2003ASPC..292..391A). For an approximation of the phase light curves of nearly-periodic pulsating stars, we use a Trigonometric Polynomial (TP) fit of the statistically optimal degree and initial period improvement using differential corrections (1994OAP.....7...49A). For the determination of parameters of "characteristic points" (minima, maxima, crossings of some constant value etc.) we use a set of methods self-reviewed in 2005ASPC..335...37A, Results of the analysis of the catalogs compiled using these programs are presented in 2014AASP....4....3A. For more complicated signals, we use "phenomenological approximations" with "special shapes" based on functions defined on sub-intervals rather on the complete interval. E. g. for the Algol-type stars we developed the NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv1212.6707A, 2015JASS...32..127A), which was compared to common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree. The method allows determine the minimal set of parameters required for the "General Catalogue of Variable Stars", as well as an extended set of phenomenological and astrophysical parameters which may be used for the classification. Totally more that 1900 variable stars were studied in our group using these methods in a frame of the "Inter-Longitude Astronomy" campaign (2010OAP....23....8A) and the "Ukrainian Virtual Observatory" project (2012KPCB...28...85V).

  4. A fresh insight into the evolutionary status and third body hypothesis of the eclipsing binaries AD Andromedae, AL Camelopardalis, and V338 Herculis

    Science.gov (United States)

    Liakos, A.; Niarchos, P.; Budding, E.

    2012-03-01

    Aims: We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. Methods: New and complete multi-filter light curves of the eclipsing binaries AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary eclipses for AL Cam and V338 Her. Results: For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses. Light curve solutions provide the means to calculate the absolute parameters of the components of the systems and reliably estimate their present evolutionary status. Conclusions: AL Cam and V338 Her are confirmed as classical Algols of relatively low mass in similar configurations. Unlike AL Cam, however, V338 Her is still transferring matter between its components, raising interest in the determinability of the evolutionary histories of Algols. AD And is found to be a detached system in which both close stars are of age ~109 yr and is probably a "non-classical" young triple, at an interesting stage of its dynamical evolution. The spectra and reduced photometric data are available in electronic form 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/539/A129

  5. Surprising Rapid Collapse of Sirius B from Red Giant to White Dwarf Through Mass Transfer to Sirius a

    Science.gov (United States)

    Yousef, Shahinaz; Ali, Ola

    2013-03-01

    Sirius was observed in antiquity as a red star. In his famous astronomy textbook the Almagest written 140 AD, Ptolemy described the star Sirius as fiery red. He curiously depicted it as one of six red-colored stars. The other five are class M and K stars, such as Arcturus and Betelgeuse. Apparent confirmation in ancient Greek and Roman sources are found and Sirius was also reported red in Europe about 1400 years ago. Sirius must have changed to a white dwarf in the night of Ascension. The star chapter in the Quran started with "by the star as it collapsed (1) your companion have not gone astray nor being misled (2), and in verse 49 which is the rotation period of the companion Sirius B around Sirius A, it is said" He is the Lord of Sirius (49). If Sirius actually was red what could have caused it to change into the brilliant bluish-white star we see today? What the naked eye perceives as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The red color indicates that the star seen then was a red giant. It looks that what they have seen in antiquity was Sirius B which was then a red giant and it collapsed to form a white dwarf. Since there is no evidence of a planetary nebula, then the red Sirius paradox can be solved in terms of stellar evolution with mass transfer. Sirius B was the most massive star which evolved to a red giant and filled the Roche lobe. Mass transfer to Sirius A occurred through the Lagrangian point. Sirius A then became more massive while Sirius B lost mass and shrank. Sirius B then collapsed abruptly into a white dwarf. In the case of Algol, Ptolmy observed it as white star but it was red at the time of El sufi. At present it is white. The rate of mass transfer from Sirius B to Sirius A, and from Algol B to A is estimated from observational data of colour change from red to bullish white to be 0

  6. Automated classification of periodic variable stars detected by the wide-field infrared survey explorer

    International Nuclear Information System (INIS)

    We describe a methodology to classify periodic variable stars identified using photometric time-series measurements constructed from the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Databases. This will assist in the future construction of a WISE Variable Source Database that assigns variables to specific science classes as constrained by the WISE observing cadence with statistically meaningful classification probabilities. We have analyzed the WISE light curves of 8273 variable stars identified in previous optical variability surveys (MACHO, GCVS, and ASAS) and show that Fourier decomposition techniques can be extended into the mid-IR to assist with their classification. Combined with other periodic light-curve features, this sample is then used to train a machine-learned classifier based on the random forest (RF) method. Consistent with previous classification studies of variable stars in general, the RF machine-learned classifier is superior to other methods in terms of accuracy, robustness against outliers, and relative immunity to features that carry little or redundant class information. For the three most common classes identified by WISE: Algols, RR Lyrae, and W Ursae Majoris type variables, we obtain classification efficiencies of 80.7%, 82.7%, and 84.5% respectively using cross-validation analyses, with 95% confidence intervals of approximately ±2%. These accuracies are achieved at purity (or reliability) levels of 88.5%, 96.2%, and 87.8% respectively, similar to that achieved in previous automated classification studies of periodic variable stars.

  7. An Orbital Stability Study of the Proposed Companions of SW Lyncis

    CERN Document Server

    Hinse, Tobias C; Wittenmyer, Robert A

    2014-01-01

    We have investigated the dynamical stability of the proposed companions orbiting the Algol type short-period eclipsing binary SW Lyncis (Kim et al. 2010). The two candidate companions are of stellar to sub-stellar nature, and were inferred from timing measurements of the system's primary and secondary eclipses. We applied well-tested numerical techniques to accurately integrate the orbits of the two companions and to test for chaotic dynamical behaviour. We carried out the stability analysis within a systematic parameter survey varying both the geometries and orientation of the orbits of the companions, as well as their masses. In all our numerical integrations we found that the proposed SW Lyn multi-body system is highly unstable on time-scales on the order of 1000 years. Our results cast doubt on the interpretation that the timing variations are caused by two companions. This work demonstrates that a straightforward dynamical analysis can help to test whether a best-fit companion-based model is a physically...

  8. 1SWASP J093010.78+533859.5: A Possible Hierarchical Quintuple System

    CERN Document Server

    Koo, Jae-Rim; Lee, Byeong-Cheol; Kim, Seung-Lee; Lee, Chung-Uk; Hong, Kyeongsoo; Lee, Dong-Joo; Rey, Soo-Chang

    2014-01-01

    We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclips- ing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data confirms the finding of Lohr et al. (2013) that the bright object A is an Algol-type detached eclipsing binary and the fainter B is a W UMa-type contact eclipsing. Using the high- resolution optical spectra, we obtained well-defined radial velocity variations of system A. Furthermore, stationary spectral lines were detected that must have originated from a further, previously unrecognized stellar component. It was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to motion blur by long exposure time. We obtained the binary parameters and the absolute dimensions of th...

  9. Phemenological Modeling of Eclipsing Binary Stars

    CERN Document Server

    Andronov, Ivan L; Chinarova, Lidia L

    2016-01-01

    We review the method NAV (New Algol Variable) first introduced in 2012Ap.....55..536A, which uses the locally-dependent shapes of eclipses in an addition to the trigonometric polynomial of the second order (which typically describes the "out-of-eclipse" part of the light curve with effects of reflection, ellipticity and O'Connell). Eclipsing binary stars are believed to show distinct eclipses only if belonging to the EA type. With a decreasing eclipse width, the statistically optimal value of the trigonometric polynomial s (2003ASPC..292..391A) drastically increases from ~2 for elliptic (EL) variables without eclipses, ~6-8 for EW and up to ~30-50 for some EA with narrow eclipses. In this case of large number of parameters, the smoothing curve becomes very noisy and apparent waves (the Gibbs phenomenon) may be seen. The NAV set of the parameters may be used for classification in the GCVS, VSX and similar catalogs. The maximal number of parameters is m=12, which corresponds to s=5, if correcting both the perio...

  10. Evolution in Binary and Triple Stars, with an application to SS Lac

    CERN Document Server

    Eggleton, P P; Eggleton, Peter P.; Kiseleva-Eggleton, Ludmila

    2001-01-01

    We present equations governing the way in which both the orbit and the intrinsic spins of stars in a close binary should evolve subject to a number of perturbing forces, including the effect of a third body in a possibly inclined wider orbit. We illustrate the solutions in some binary-star and triple-star situations: tidal friction in a wide but eccentric orbit of a radio pulsar about a B star, the Darwin and eccentricity instabilities in a more massive but shorter-period massive X-ray binary, and the interaction of tidal friction with Kozai cycles in a triple such as Algol (beta-Per), at an early stage in that star's life when all 3 components were ZAMS stars. We also attempt to model in some detail the interesting triple system SS Lac, which stopped eclipsing in about 1950. We find that our model of SS Lac is quite constrained by the relatively good observational data of this system, and leads to a specific inclination (29 deg) of the outer orbit relative to the inner orbit at epoch zero (1912). Although th...

  11. Time-series spectroscopy of the pulsating eclipsing binary XX Cephei

    CERN Document Server

    Koo, Jae-Rim; Hong, Kyeongsoo; Kim, Seung-Lee; Lee, Chung-Uk

    2016-01-01

    Oscillating Algol-type eclipsing binaries (oEA) are very interesting objects that have three observational features of eclipse, pulsation, and mass transfer. Direct measurement of their masses and radii from the double-lined radial velocity data and photometric light curves would be the most essential for understanding their evolutionary process and for performing the asteroseismological study. We present the physical properties of the oEA star XX Cep from high-resolution time-series spectroscopic data. The effective temperature of the primary star was determined to be 7,946 $\\pm$ 240 K by comparing the observed spectra and the Kurucz models. We detected the absorption lines of the secondary star, which had never been detected in previous studies, and obtained the radial velocities for both components. With the published $BVRI$ light curves, we determined the absolute parameters for the binary via Wilson-Devinney modeling. The masses and radii are $M_{1} = 2.49 \\pm 0.06$ $M_\\odot$, $M_{2} = 0.38 \\pm 0.01$ $M_...

  12. PHOTOMETRIC PROPERTIES OF THE INTERACTING BINARY BO MONOCEROTIS: EVIDENCE FOR MAGNETIC ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Phillip A.; Yuhas, Bernard J., E-mail: preed@kutztown.edu, E-mail: byuha055@live.kutztown.edu [Department of Physical Sciences, Kutztown University, Kutztown, PA 19530 (United States)

    2013-05-15

    BO Monocerotis (BO Mon) is a severely neglected short-period (2.23 days) Algol-type eclipsing binary star system undergoing angular momentum variations that are likely due to the evolved secondary star experiencing cycles of magnetic activity. We present the first CCD light curves of BO Mon, which were observed at the Kutztown University Observatory (Kutztown, PA) in 2012 using B, V, and I filters. The analysis presented here is the first of its kind for BO Mon and provides the first physical model of the system's parameters. We also incorporate over 40 yr of published times of minimum light to provide a new ephemeris curve and perform a period study that greatly improves, while differing significantly from, an earlier ephemeris analysis that was done more than 13 yr ago. The observed variations in BO Mon's orbital period supply evidence for mass transfer and magnetic activity and our photometric model affords the basic properties of the system for use in future photometric and spectroscopic studies.

  13. Astrometric and Light-travel Time Orbits to Detect Low-mass Companions A Case Study of the Eclipsing System R Canis Majoris

    CERN Document Server

    Ribas, I; Guinan, E F; Ribas, Ignasi; Arenou, Frederic; Guinan, Edward F.

    2002-01-01

    We discuss a method to determine orbital properties and masses of low-mass bodies orbiting eclipsing binaries. The analysis combines long-term eclipse timing modulations (light-travel time or LTT effect) with short-term, high-accuracy astrometry. As an illustration of the method, the results of a comprehensive study of Hipparcos astrometry and over a hundred years of eclipse timings of the Algol-type eclipsing binary R Canis Majoris are presented. A simultaneous solution of the astrometry and the LTTs yields an orbital period of P_12=92.8+/-1.3 yr, an LTT semiamplitude of 2574+/-57 s, an angular semi-major axis of a_12=117+/-5 mas, and values of the orbital eccentricity and inclination of e_12=0.49+/-0.05, and i_12=91.7+/-4.7 deg, respectively. Adopting the total mass of R CMa of M_12=1.24+/-0.05 Mo, the mass of the third body is M_3=0.34+/-0.02 Mo and the semi-major axis of its orbit is a_3=18.7+/-1.7 AU. From its mass, the third body is either a dM3-4 star or, more unlikely, a white dwarf. With the upcoming...

  14. Stellar Astrophysics with SIM and Optical Long Baseline Interferometry

    Science.gov (United States)

    Ridgway, Stephen T.; Aufdenberg, J. P.; Boyajian, T.; Gies, D.; Howell, S. B.; Kervella, P.; Merand, A.; Richardson, N.

    2009-01-01

    SIM astrometry can be used in combination with precision ground-based measurements, particularly optical interferometry, and supporting modeling, to address fundamental questions in stellar physics. We will extend an on-going study of Cepheid stars, with emphasis on resolution of possible biases in the use of the P-L relation, aiming for a confidence level of better than 1%. We will determine the radii, Teff, luminosity, and in some cases masses, of massive stars with sufficient accuracy to validate models of their structure and evolution with dramatically improved discrimination. We will determine the orbits of post-Algol systems, to test the hypothesis that they are the precursors to Cataclysmic Variable stars and the wide variety of evolved objects that they produce. We will measure the radii of nearby stars to support asteroseismological studies of the stellar interiors. For all measurements here proposed for SIM, GAIA will not provide a realistic alternative, owing to brightness of the targets, expected errors, and/or required observational cadence.

  15. Towards Bayesian Machine Learning for Estimating Parameters of Accretion Disk Models for SPH Simulations

    Science.gov (United States)

    Goel, Amit; Montgomery, Michele; Wiegand, Paul

    2016-01-01

    Accretion disks are ubiquitous in Active Galactic Nuclei, in protostellar systems forming protoplanets, and in close binary star systems such as X-ray binaries, Cataclysmic Variables, and Algols, for example. Observations such as disk tilt are found in all of these different accreting system types, suggesting a common physics must be present. To understand the common connections between these different system types, which can help us understand their unique evolutions, we need to better understand the physics of accretion. For example, viscosity is typically a constant value in the disk of a system that is in a specific state such as a quiescent state. However, viscosity can't be constant throughout the disk, especially at the boundaries. To learn more about viscosity and other common parameters in these disk, we use Bayesian Inference and Markov Chain Monte Carlo techniques to make predictions of events to come in the numerical simulations of these accreting disks. In this work, we present our techniques and initial findings.

  16. Physical properties of the eclipsing Delta Sct star KIC 10661783

    CERN Document Server

    Lehmann, H; Tkachenko, A; Pavlovski, K

    2013-01-01

    KIC 10661783 is an eclipsing binary that shows Delta Sct-like oscillations. More than 60 pulsation frequencies have been detected in its light curve as observed by the Kepler satellite. We want to determine the fundamental stellar and system parameters of the eclipsing binary as a precondition for asteroseismic modelling of the pulsating component and to establish whether the star is a semi-detached Algol-type system. We measured the radial velocities of both components from new high-resolution spectra using TODCOR and compute the orbit using PHOEBE. We used the KOREL program to decompose the observed spectra into its components, and analysed the decomposed spectra to determine the atmospheric parameters. For this, we developed a new computer program for the normalisation of the KOREL output spectra. Fundamental stellar parameters are determined by combining the spectroscopic results with those from the analysis of the Kepler light curve. We obtain Teff, logg, vsini, and the absolute masses and radii of the c...

  17. First results from the RAO Variable Star Search Program: I. Background, Procedure, and Results from RAO Field 1

    CERN Document Server

    Williams, Michael D

    2011-01-01

    We describe an ongoing variable star search program and present the first reduced results of a search in a 19 square degree (4.4\\circle x 4.4\\circle) field centered on J2000 {\\alpha} = 22:03:24, {\\delta} = +18:54:32. The search was carried out with the Baker-Nunn Patrol Camera located at the Rothney Astrophysical Observatory in the foothills of the Canadian Rockies. A total of 26,271 stars were detected in the field, over a range of about 11-15 (instrumental) magnitudes. Our image processing made use of the IRAF version of the DAOPHOT aperture photometry routine and we used the ANOVA method to search for periodic variations in the light curves. We formally detected periodic variability in 35 stars, that we tentatively classify according to light curve characteristics: 6 EA (Algol), 5 EB ({\\beta} Lyrae), 19 EW (W UMa), and 5 RR (RR Lyrae) stars. Eleven of the detected variable stars have been reported previously in the literature. The eclipsing binary light curves have been analyzed with a package of light cur...

  18. The most plausible explanation of the cyclical period changes in close binaries: the case of the RS CVn-type binary WW Dra

    CERN Document Server

    Liao, W -P

    2010-01-01

    We searched the orbital period changes in 182 EA-type (including the 101 Algol systems used by \\cite{hal89}), 43 EB-type and 53 EW-type binaries with known both the mass ratio and the spectral type of their secondary components. We reproduced and improved the same diagram as Hall's (1989) according to the new collected data. Our plots do not support the conclusion derived by \\cite{hal89} that all cases of cyclical period changes are restricted to binaries having the secondary component with spectral types later than F5. The presence of period changes also among stars with secondary component of early type indicates that the magnetic activity is one cause, but not the only one, for the period variation. It is discovered that cyclic period changes, likely due to the presence of a third body are more frequent in EW-type binaries among close binaries. Therefore, the most plausible explanation of the cyclical period changes is the LTTE via the presence of a third body. By using the century-long historical record o...

  19. The hot subdwarf in the eclipsing binary HD 185510

    Science.gov (United States)

    Jeffery, C. S.; Simon, Theodore; Evans, T. L.

    1992-01-01

    High-resolution spectroscopic measurements of radial velocity are employed to characterize the eclipsing binary HD 185510 in terms of masses and evolutionary status. The IUE is used to obtain the radial velocities which indicate a large mass ratio Mp/Ms of 7.45 +/- 0.15, and Teff is given at 25,000 +/- 1000 K based on Ly alpha and UV spectrophotometry. Photometric observations are used to give an orbital inclination of between 90 and 70 deg inclusive, leading to masses of 0.31-0.37 and 2.3-2.8 solar mass for the hot star and the K star, respectively. The surface gravity of HD 185510B is shown to be higher than those values for sdB stars suggesting that the object is a low-mass white dwarf that has not reached its fully degenerate configuration. The object is theorized to be a low-mass helium main-sequence star or a nascent helium degenerate in a post-Algol system.

  20. Analysis of the southern pre-contact W UMa binary ZZ Eridani: A 34 year period study yields a possible low-mass companion

    Energy Technology Data Exchange (ETDEWEB)

    Samec, R. G. [Faculty Research Associate, Pisgah Astronomical Research Institute, One Pari Drive, Rosman, NC 28772 (United States); Clark, J. D. [Astronomy Group, Physics and Engineering Department, Bob Jones University, 1700 Wade Hampton Boulevard, Greenville, SC 29614 (United States); Hamme, W. Van [Physics Department, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Faulkner, D. R. [University of South Carolina, Lancaster, 476 Hubbard Drive Lancaster, SC 29720 (United States)

    2015-02-01

    Complete Bessel BVRI light curves of ZZ Eridani [2MASS J04130109-1044545, HV 6280, NSVS 14888164 α(2000) = 04{sup h}13{sup m}1{sub ·}{sup s}10, δ(2000) = −10°44′54{sub ·}{sup ″}5 (ICRS), V = 13.9-14.4-15.0] are observed and analyzed. The system is a southern pre-contact W UMa binary. Its light curve has the appearance of an Algol (EA) light curve, however, it is made up of dwarf solar-type components with a period of only 0.4521 days. Our 34 year period study yields a sinusoidal fit or an increasing quadratic fit. The sinusoid may indicate that a third body is orbiting the close binary. The lower-limit mass of the third body is near that of the brown dwarf limit (0.095 M α). Also included is an improved ephemeris, a mass ratio search, and a simultaneous BVRI Wilson–Devinney solution.

  1. Kozai Cycles and Tidal Friction

    Energy Technology Data Exchange (ETDEWEB)

    L, K; P.P., E

    2009-07-17

    Several studies in the last three years indicate that close binaries, i.e. those with periods of {approx}< 3 d, are very commonly found to have a third body in attendance. We argue that this proves that the third body is necessary in order to make the inner period so short, and further argue that the only reasonable explanation is that the third body causes shrinkage of the inner period, from perhaps a week or more to the current short period, by means of the combination of Kozai cycles and tidal friction (KCTF). In addition, once KCTF has produced a rather close binary, magnetic braking also combined with tidal friction (MBTF) can decrease the inner orbit further, to the formation of a contact binary or even a merged single star. Some of the products of KCTF that have been suggested, either by others or by us, are W UMa binaries, Blue Stragglers, X-ray active BY Dra stars, and short-period Algols. We also argue that some components of wide binaries are actually merged remnants of former close inner pairs. This may include such objects as rapidly rotating dwarfs (AB Dor, BO Mic) and some (but not all) Be stars.

  2. Photometric solution and frequency analysis of the oEA system EW Boo

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X. B.; Wang, K. [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Luo, Y. P., E-mail: xzhang@bao.ac.cn [School of Physics and Electronic Information, China West Normal University, Nanchong 637009 (China)

    2015-03-01

    We present the first photometric solution and frequency analysis of the neglected oscillating Algol-type (oEA) binary EW Boo. B- and V-band light curves of the star were obtained on 11 nights in 2014. Using the Wilson–Devinney code, the eclipsing light curves were synthesized and the first photometric solution was derived for the binary system. The results reveal that EW Boo could be a semi-detached system with the less-massive secondary component filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. Frequency analysis of residual light shows multi-mode pulsation with the dominant period at 0.01909 days. A preliminary mode identification suggests that the star could be pulsating in non-radial (l = 1) modes. The long-term orbital period variation of the system was also investigated for the first time. An improved orbital period and new ephemerides of the eclipsing binary are given. The O−C analysis indicates a secular period increasing at a rate of dP/dt=2.9×10{sup −7} days yr{sup −1}, which could be interpreted as mass transfer from the cooler secondary to the primary component.

  3. Photometric solution and frequency analysis of the oEA system EW Boo

    International Nuclear Information System (INIS)

    We present the first photometric solution and frequency analysis of the neglected oscillating Algol-type (oEA) binary EW Boo. B- and V-band light curves of the star were obtained on 11 nights in 2014. Using the Wilson–Devinney code, the eclipsing light curves were synthesized and the first photometric solution was derived for the binary system. The results reveal that EW Boo could be a semi-detached system with the less-massive secondary component filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. Frequency analysis of residual light shows multi-mode pulsation with the dominant period at 0.01909 days. A preliminary mode identification suggests that the star could be pulsating in non-radial (l = 1) modes. The long-term orbital period variation of the system was also investigated for the first time. An improved orbital period and new ephemerides of the eclipsing binary are given. The O−C analysis indicates a secular period increasing at a rate of dP/dt=2.9×10−7 days yr−1, which could be interpreted as mass transfer from the cooler secondary to the primary component.

  4. A new eclipsing binary system with a pulsating component detected by CoRoT

    CERN Document Server

    Sokolovsky, K; Hareter, M; Damiani, C; Balaguer-Nunez, L; Ribas, I

    2010-01-01

    We report the discovery of CoRoT 102980178 (R.A.= 06:50:12.10, Dec.= -02:41:21.8, J2000) an Algol-type eclipsing binary system with a pulsating component (oEA). It was identified using a publicly available 55 day long monochromatic lightcurve from the CoRoT initial run dataset (exoplanet field). Eleven consecutive 1.26m deep total primary and the equal number of 0.25m deep secondary eclipses (at phase 0.50) were observed. The following light elements for the primary eclipse were derived: HJD_MinI= 2454139.0680 + 5.0548d x E. The lightcurve modeling leads to a semidetached configuration with the photometric mass ratio q=0.2 and orbital inclination i=85 deg. The out-of-eclipse lightcurve shows ellipsoidal variability and positive O'Connell effect as well as clear 0.01m pulsations with the dominating frequency of 2.75 c/d. The pulsations disappear during the primary eclipses, which indicates the primary (more massive) component to be the pulsating star. Careful frequency analysis reveals the second independent p...

  5. V1898 CYGNI: AN INTERACTING ECLIPSING BINARY IN THE VICINITY OF NORTH AMERICA NEBULA

    Directory of Open Access Journals (Sweden)

    A. Dervisoglu

    2011-01-01

    Full Text Available Presentamos observaciones espectroscópicas de la binaria eclipsante tipo Algol, de doble línea, V1898 Cygni. El análisis de las curvas de luz en las bandas BV nos lleva a una determinación de los parmetros fundamentales de las componentes de V1898 Cygni. Los parámetros absolutos son: M1 = 6.054 ± 0.037 M, M2 = 1.162 ± 0.011 M, R1 = 3.526 ± 0.009 R, R2 = 2.640 ± 0.010 R, Teff1 = 18000 ± 600 K, y Teff2 = 6200 ± 200 K. Analizamos los residuos entre los tiempos observados y calculados para el eclipse medio y obtenemos una tasa de cambio del periodo de P /P = 6.68×107 yr1. Estimamos una tasa de transferencia de masa de 1.88×107 M¿ por año. Utilizando las magnitudes infrarojas JHK y las correcciones bolométricas para la estrella primaria, calculamos la distancia al sistema V1898 Cyg como 501 ±5 pc. Las componentes de los movimientos propios del sistema presentan alguna información sobre su pertenencia a la Nebulosa de Norteamérica.

  6. Mathematical model of various statements of C-type Language

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Srivastav

    2013-12-01

    Full Text Available Some of the important components of high level languages are statements, keywords, variable declarations, arrays, user defined functions etc. In case of object oriented programming language we use class, object, inheritance, operator overloading, function overloading, polymorphism etc. There are some common category of statements such as control statement, loop statements etc. Pointers are also one important concept in C-language. User defined functions, function subprograms or subroutines are also important concepts in different programming languages. The language like ALGOL was developed using Chomsky context free grammar. The similar concept used in C-type languages. The high level languages are now based on mathematical derivations and logic. Most of the components of any high level language can be obtained from simple mathematical logic and derivations. In the present study the authors have tried to give some unified mathematical model of few statements, arrays, user defined functions of C-language. However, the present method may further be extended to any other high level language.

  7. Large X-ray Flares on Stars Detected with MAXI/GSC: A Universal Correlation between the Duration of a Flare and its X-ray Luminosity

    CERN Document Server

    Tsuboi, Yohko; Sugawara, Yasuharu; Kawagoe, Atsushi; Kaneto, Soichiro; Iizuka, Ryo; Matsumura, Takanori; Nakahira, Satoshi; Higa, Masaya; Matsuoka, Masaru; Sugizaki, Mutsumi; Ueda, Yoshihiro; Kawai, Nobuyuki; Morii, Mikio; Serino, Motoko; Mihara, Tatehiro; Tomida, Hiroshi; Ueno, Shiro; Negoro, Hitoshi; Daikyuji, Arata; Ebisawa, Ken; Eguchi, Satoshi; Hiroi, Kazuo; Ishikawa, Masaki; Isobe, Naoki; Kawasaki, Kazuyoshi; Kimura, Masashi; Kitayama, Hiroki; Kohama, Mitsuhiro; Kotani, Taro; Nakagawa, Yujin E; Nakajima, Motoki; Ozawa, Hiroshi; Shidatsu, Megumi; Sootome, Tetsuya; Sugimori, Kousuke; Suwa, Fumitoshi; Tsunemi, Hiroshi; Usui, Ryuichi; Yamamoto, Takayuki; Yamaoka, Kazutaka; Yoshida, Atsumasa

    2016-01-01

    23 giant flares from 13 active stars (eight RS CVn systems, one Algol system, three dMe stars and one YSO) were detected during the first two years of our all-sky X-ray monitoring with the gas propotional counters (GSC) of the Monitor of All-sky X-ray Image (MAXI). The observed parameters of all of these MAXI/GSC flares are found to be at the upper ends for stellar flares with the luminosity of 10^(31-34) ergs s-1 in the 2-20 keV band, the emission measure of 10^(54-57) cm-3, the e-folding time of 1 hour to 1.5 days, and the total radiative energy released during the flare of 10^(34-39) ergs. Notably, the peak X-ray luminosity of 5(3-9)*10^33 ergs s-1 in the 2-20 keV band was detected in one of the flares on II Peg, which is one of the, or potentially the, largest ever observed in stellar flares. X-ray flares were detected from GT Mus, V841 Cen, SZ Psc, and TWA-7 for the first time in this survey. Whereas most of our detected sources are multiple-star systems, two of them are single stars (YZ CMi and TWA-7). ...

  8. THERMOS, Space-Dependent Thermal Flux in 1-D Slab or Cylinder

    International Nuclear Information System (INIS)

    1 - Nature of physical problem solved: Computes the scalar thermal neutron spectrum as function of position in a one-dimensional slab (THERMOS-1) or cylindrical cell (THERMOS-2). Isotropic neutron scattering in the laboratory system is assumed. The slowing down source is computed from elastic scattering of the neutrons in a 1/E epithermal flux. Either a reflecting or vacuum boundary can be chosen. 2 - Method of solution: The velocity and space variables are replaced by discrete values. Scattering and collision probability matrices are computed and the neutron balance equation is solved by iterative techniques. A combination of a Gauss iteration, renormalization and extrapolation is used to accelerate convergence. 3 - Restrictions on the complexity of the problem: Maximum 30 velocity groups, 20 space points, 5 mixtures (assigned arbitrarily to the space points) composed of maximum 10 isotopes. An additional 10 isotopes can be specified for activation calculations and cross section averaging. The Library has received the 7090 version of this programme through the CETIS programmotheque. The 7040 version was written by the Universite libre de Bruxelles. ALGOL version was offered by Delft (Reactor Instituut Delft, Netherlands). A version for ICL computer was received from Central Research Institute for Physics of the Hungarian Academy of Sciences Budapest, Hungary

  9. Modeling the Accretion Structure of AU Mon

    CERN Document Server

    Atwood-Stone, Corwin; Richards, Mercedes T; Budaj, Jan; Peters, Geraldine J

    2012-01-01

    AU Mon is a long-period (11.113 d) Algol-type binary system with a persistent accretion disk that is apparent as double-peaked H-alpha emission. We present previously unpublished optical spectra of AU Mon which were obtained over several years with dense orbital phase coverage. We utilize these data, along with archival UV spectra, to model the temperature and structure of the accretion disk and the gas stream. Synthetic spectral profiles for lines including H-alpha, H-beta, and the Al III and Si IV doublets were computed with the Shellspec program. The best match between the model spectra and the observations is obtained for an accretion disk of inner/outer radius 5.1/23 R_sun, thickness of 5.2 R_sun, density of 1.0e-13 g/cm^3, and maximum temperature of 14000 K, along with a gas stream at a temperature of ~8000 K transferring ~2.4e-9 M_sun/yr. We show H-alpha Doppler tomograms of the velocity structure of the gas, constructed from difference profiles calculated through sequentially subtracting contributions...

  10. A Multiwavelength Study of RZ Cassiopeiae: The XMM-Newton/VLA Campaign

    CERN Document Server

    Audard, M; Güdel, M; Audard, Marc; Donisan, Julius R.; Guedel, Manuel

    2004-01-01

    XMM-Newton and the VLA simultaneously observed the eclipsing Algol-type binary RZ Cassiopeiae in August 2003. The secondary eclipse (K3 IV companion behind the A3 V primary) was placed at the center of the 15-hour radio campaign, while the X-ray satellite monitored a full 1.2-day orbital period. We present results of the X-ray and radio campaigns. The X-ray light curve shows significant modulation probably related to rotational modulation and active region evolution, and even small flares. However, the X-ray eclipse is not deep, implying that the coronal X-ray emitting material is spatially extended. The Reflection Grating Spectrometer (RGS) spectrum shows a variety of bright emission lines from Fe, Ne, O, N. A strong [C/N] depletion probably reflects the surface composition of the secondary which fills its Roche lobe and loses material onto the primary. The O~\\textsc{vii} He-like triplet reflects a low forbidden-to-intercombination ratio; while it generally suggests high electron densities, the ratio is here...

  11. Use of different programs for calculating the flux density of neutrons activating sodium in the secondary circuit of a NPP with the BN-600 reactor

    International Nuclear Information System (INIS)

    Possibilities of application of the RADAR, TVK-2D and MMKFK program complexes to calculate the BN-600 type reactor shields are analyzed. TVK-2D program (ALGOL-DDR, BESM-6 computer) is designed for two-dimensional calculations of reactors in diffusion multigroup finite-difference approximation using classical and unified perturbation theory. The RADAR system (FORTRAN-4, BESM-6 computer) realizes Boltzmann equation solution by iterative synthesis method in multigroup diffusion approximation. The MMKFK complex (FORTRAN, BESM-6 computer) is used to calculate radiation transport in reactors and cells. The complex is improved: at large ratioes of neutron flux attenuation the methods of splitting and roulette are realized. Calculational results of the integral by energy and mean by zones values of neutron flux density in radial shield and sodium activity in the secondary coolant circuits are presented. Good conformity of the data obtained is pointed out. Conclusion is made about the applicability of the program systems investigated to calculate fast reactor shields at different stages of design. The RADAR system due to its quick operation will be more efficient at the initial stages, while the MMKFK system - at final ones, when high accuracy of calculation is required

  12. The Kepler eclipsing system KIC 5621294 and its substellar companion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Woo; Hong, Kyeongsoo; Hinse, Tobias Cornelius, E-mail: jwlee@kasi.re.kr, E-mail: kshong@kasi.re.kr, E-mail: tchinse@gmail.com [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2015-03-01

    We present the physical properties of KIC 5621294, showing light and timing variations from the Kepler photometry. Its light curve displays partial eclipses and the O’Connell effect, with Max II fainter than Max I, which was fitted quite well by applying third-body and spot effects to the system. The results indicate that the eclipsing pair is a classical Algol-type system with parameters of q = 0.22, i = 76.°8, and Δ(T{sub 1}−T{sub 2}) = 4235 K, in which the detached primary component fills about 77% of its limiting lobe. Striking discrepancies exist between the primary and secondary eclipse times obtained with the method of Kwee and van Woerden. These are mainly caused by surface inhomogeneities due to spot activity detected in our light curve synthesis. The 1253 light curve timings from the Wilson–Devinney code were used for a period study. It was found that the orbital period of KIC 5621294 has varied due to periodic variation overlaid on a downward parabola. The sinusoidal variation with a period of 961 days and a semi-amplitude of 22.5 s most likely arises from a light-time effect due to a third component with a mass of M{sub 3}sini{sub 3} = 46.9 M{sub Jup}, which is in good agreement with that calculated from the light curve itself. If its orbital inclination is larger than about 40°, the mass of the circumbinary object would possibly match a brown dwarf. The parabolic variation could not be fully explained by either a mass transfer between the binary components or angular momentum via magnetic braking. It is possible that the parabola may be the only observed part of a period modulation caused by the presence of another companion in a wider orbit.

  13. Time-series Spectroscopy of the Pulsating Eclipsing Binary XX Cephei

    Science.gov (United States)

    Koo, Jae-Rim; Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Lee, Chung-Uk

    2016-03-01

    Oscillating Algol-type eclipsing binaries (oEA) are very interesting objects that have three observational features of eclipse, pulsation, and mass transfer. Direct measurement of their masses and radii from the double-lined radial velocity data and photometric light curves would be the most essential for understanding their evolutionary process and for performing the asteroseismological study. We present the physical properties of the oEA star XX Cep from high-resolution time-series spectroscopic data. The effective temperature of the primary star was determined to be 7946 ± 240 K by comparing the observed spectra and the Kurucz models. We detected the absorption lines of the secondary star, which had never been detected in previous studies, and obtained the radial velocities for both components. With the published BVRI light curves, we determined the absolute parameters for the binary via Wilson-Devinney modeling. The masses and radii are {M}1=2.49+/- 0.06 {M}⊙ , {M}2=0.38+/- 0.01 {M}⊙ , {R}1=2.27+/- 0.02 {R}⊙ , and {R}2=2.43+/- 0.02 {R}⊙ , respectively. The primary star is about 45% more massive and 60% larger than the zero-age main sequence stars with the same effective temperature. It is probably because XX Cep has experienced a very different evolutionary process due to mass transfer, contrasting with the normal main sequence stars. The primary star is located inside the theoretical instability strip of δ Sct-type stars on the HR diagram. We demonstrated that XX Cep is an oEA star, consisting of a δ Sct-type pulsating primary component and an evolved secondary companion.

  14. Quasi-Periodic Long-Term Quadrature Light Variability in Early Type Interacting Binary Systems

    Science.gov (United States)

    Peters, Geraldine Joan

    2015-08-01

    Four years of Kepler observations have revealed a class of Algol-type binaries in which the relative brightness of the quadrature light varies from > 1 to trailing hemisphere) variables. Although L/T inequality in eclipsing binaries has been noted from ground-based photometry by several observers since the early 1950s, the regular or quasi-regular switching between maxima is new. Twenty L/T systems have so far been found in the Kepler database and at least three classes of L/T behavior have been identified. In this presentation I will give an update on the L/T phenomenon gleaned from the Kepler and K2 databases. The Kepler and K2 light curves are being analyzed with the 2015 version of the Wilson-Devinney (WD) program that includes major improvements in modeling star spots (i.e. spot motions due to drift and stellar rotation and spot growth and decay). The prototype L/T variable is WX Draconis (A8V + K0IV, P=1.80 d) which shows L/ T light variations of 2-3%. The primary is a delta Scuti star with a dominant pulsation period of 41 m. Preliminary analysis of the WX Dra data suggests that the L/T variability can be fit with either an accretion hot spot on the primary (T = 2.3 Tphot) that jumps in longitude or a magnetic cool spotted region on the secondary. If the latter model is correct the dark region must occupy at least 20% of the surface of the facing hemisphere of the secondary if it is completely black, or a larger area if not completely black. In both hot and cool spot scenarios magnetic fields must play a role in the activity. Support from NASA grants NNX11AC78G and NNX12AE44G and USC’s Women in Science and Engineering (WiSE) program is greatly appreciated.

  15. KOI 1224: A FOURTH BLOATED HOT WHITE DWARF COMPANION FOUND WITH KEPLER

    International Nuclear Information System (INIS)

    We present an analysis and interpretation of the Kepler binary system KOI 1224. This is the fourth binary found with Kepler that consists of a thermally bloated, hot white dwarf in a close orbit with a more or less normal star of spectral class A or F. As we show, KOI 1224 contains a white dwarf with Teff = 14, 700 ± 1000 K, mass = 0.22 ± 0.02 M☉, and radius = 0.103 ± 0.002 R☉, and an F-star companion of mass 1.59 ± 0.06 M☉ that is somewhat beyond its terminal-age main sequence. The orbital period is quite short at 2.69802 days. The ingredients that are used in the analysis are the Kepler binary light curve, including the detection of the Doppler boosting effect; the NUV and FUV fluxes from the GALEX images of this object; an estimate of the spectral type of the F-star companion; and evolutionary models of the companion designed to match its effective temperature and mean density. The light curve is modeled with a new code named Icarus which we describe in detail. Its features include the full treatment of orbital phase-resolved spectroscopy, Doppler boosting, irradiation effects, and transits/eclipses, which are particularly suited to irradiated eclipsing binaries. We interpret the KOI 1224 system in terms of its likely evolutionary history. We infer that this type of system, containing a bloated hot white dwarf, is the direct descendant of an Algol-type binary. In spite of this basic understanding of the origin of KOI 1224, we discuss a number of problems associated with producing a system with an orbital period this short.

  16. Analysis of selected Kepler Mission planetary light curves

    Science.gov (United States)

    Rhodes, M. D.; Budding, E.

    2014-06-01

    We have modified the graphical user interfaced close binary system analysis program CurveFit to the form WinKepler and applied it to 16 representative planetary candidate light curves found in the NASA Exoplanet Archive (NEA) at the Caltech website http://exoplanetarchive.ipac.caltech.edu, with an aim to compare different analytical approaches. WinKepler has parameter options for a realistic physical model, including gravity-brightening and structural parameters derived from the relevant Radau equation. We tested our best-fitting parameter-sets for formal determinacy and adequacy. A primary aim is to compare our parameters with those listed in the NEA. Although there are trends of agreement, small differences in the main parameter values are found in some cases, and there may be some relative bias towards a 90∘ value for the NEA inclinations. These are assessed against realistic error estimates. Photometric variability from causes other than planetary transits affects at least 6 of the data-sets studied; with small pulsational behaviour found in 3 of those. For the false positive KOI 4.01, we found that the eclipses could be modelled by a faint background classical Algol as effectively as by a transiting exoplanet. Our empirical checks of limb-darkening, in the cases of KOI 1.01 and 12.01, revealed that the assigned stellar temperatures are probably incorrect. For KOI 13.01, our empirical mass-ratio differs by about 7 % from that of Mislis and Hodgkin (Mon. Not. R. Astron. Soc. 422:1512, 2012), who neglected structural effects and higher order terms in the tidal distortion. Such detailed parameter evaluation, additional to the usual main geometric ones, provides an additional objective for this work.

  17. The VLT-FLAMES Tarantula Survey. XXIII. Two massive double-lined binaries in 30 Doradus

    Science.gov (United States)

    Howarth, I. D.; Dufton, P. L.; Dunstall, P. R.; Evans, C. J.; Almeida, L. A.; Bonanos, A. Z.; Clark, J. S.; Langer, N.; Sana, H.; Simón-Díaz, S.; Soszyński, I.; Taylor, W. D.

    2015-10-01

    Aims: We investigate the characteristics of two newly discovered short-period, double-lined, massive binary systems in the Large Magellanic Cloud, VFTS 450 (O9.7 II-Ib + O7::) and VFTS 652 (B1 Ib + O9: III:). Methods: We perform model-atmosphere analyses to characterise the photospheric properties of both members of each binary (denoting the "primary" as the spectroscopically more conspicuous component). Radial velocities and optical photometry are used to estimate the binary-system parameters. Results: We estimate Teff = 27 kK, log g = 2.9 (cgs) for the VFTS 450 primary spectrum (34 kK, 3.6: for the secondary spectrum); and Teff = 22 kK, log g = 2.8 for the VFTS 652 primary spectrum (35 kK, 3.7: for the secondary spectrum). Both primaries show surface nitrogen enrichments (of more than 1 dex for VFTS 652), and probable moderate oxygen depletions relative to reference LMC abundances. We determine orbital periods of 6.89 d and 8.59 d for VFTS 450 and VFTS 652, respectively, and argue that the primaries must be close to filling their Roche lobes. Supposing this to be the case, we estimate component masses in the range ~20-50 M⊙. Conclusions: The secondary spectra are associated with the more massive components, suggesting that both systems are high-mass analogues of classical Algol systems, undergoing case-A mass transfer. Difficulties in reconciling the spectroscopic analyses with the light-curves and with evolutionary considerations suggest that the secondary spectra are contaminated by (or arise in) accretion disks. Based on observations obtained at the European Southern Observatory Very Large Telescope (VLT) as part of programmes 182.D-0222 and 090.D-0323.Tables 2, 3, and 8 are available in electronic form at http://www.aanda.org

  18. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J., E-mail: mrichards@astro.psu.edu, E-mail: asc5097@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2014-11-10

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The Hα tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  19. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    International Nuclear Information System (INIS)

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The Hα tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  20. Binary Stars "Flare" With Predictable Cycles, Analysis of Radio Observations Reveals

    Science.gov (United States)

    2002-06-01

    Astronomers have completed a 5-year campaign to monitor continuously radio flares from two groups of binary star systems. This survey is of special interest because it provides evidence that certain binary star systems have predictable activity cycles like our Sun. The survey, which ran from January 1995 to October 2000, was conducted with the National Science Foundation's (NSF) Green Bank Interferometer. The report was presented at the American Astronomical Society (AAS) meeting in Albuquerque, New Mexico, by Mercedes Richards of the University of Virginia, and her collaborators Elizabeth Waltman of the Naval Research Laboratory, and Frank Ghigo of the National Radio Astronomy Observatory (NRAO). "This long-term survey was critical to our understanding of the short- and long-term magnetic cycles of these intriguing star systems," said Richards. The survey focused on the binary star systems Beta Persei and V711 Tauri -- both are about 95 light-years from Earth. Beta Persei is the prototype of the "Algol" class of interacting binary stars. An Algol system contains a hot, blue, main sequence star, along with a cool, orange/red star that is more active than our Sun. V711 Tauri is an "RS Canum Venaticorum" binary, which contains two cool stars that behave like our Sun. "Our survey was the longest-running continuous radio flare survey of Algol or RS Canum Venaticorum binary star systems," said Richards. A flare is an enormous explosion on the surface of a star, which is accompanied by a release of magnetic energy. Flares can be detected over the full range of wavelengths from gamma rays to the radio. It is estimated that the energy release in a flare on the Sun is equivalent to a billion megatons of TNT. The strength of the magnetic field and the amount of activity it displays, like sunspots and flares, are directly related to the rotation or "spin" of the star. In Beta Persei and V711 Tauri, the cool star spins once every 3 days, compared to once every month in the

  1. Graeco-Roman Astro-Architecture: The Temples of Pompeii

    Science.gov (United States)

    Tiede, Vance R.

    2014-01-01

    Roman architect Marcus Vetruvius Pollio (ca. 75-15 BC) wrote, “[O]ne who professes himself as an architect should be…acquainted with astronomy and the theory of the heavens…. From astronomy we find the east, west, south, and north, as well as the theory of the heavens, the Equinox, Solstice and courses of the Stars.” (De Architectura Libri Decem I:i:3,10). In order to investigate the role of astronomy in temple orientation, the author conducted a preliminary GIS DEM/Satellite Imaging survey of 11 temples at Pompeii, Italy (N 40d 45', E 14d 29'). The GIS survey measured the true azimuth and horizon altitude of each temple’s major axis and was field checked by a Ground Truth survey with theodolite and GPS, 5-18 April 2013. The resulting 3D vector data was analyzed with Program STONEHENGE (Hawkins 1983, 328) to identify the local skyline declinations aligned with the temple major axes. Analysis suggests that the major axes of the temples of Apollo, Jupiter and Venus are equally as likely to have been oriented to Pompeii’s urban grid, itself oriented NW-SE on Mt. Vesuvius’ slope and hydraulic gradient to optimize urban sewer/street drainage (cf. Hodge 1992). However, the remaining nine temples appear to be oriented to astronomical targets on the local horizon associated with Graeco-Roman calendrics and mythology. TEMPLE/ DATE/ MAJOR AXIS ASTRO-TARGET (Skyline Declination in degrees) Public Lares/AD 50/ Cross-Quarter 7 Nov/3 Feb Sun Set, Last Gleam (-16.5) Vespsian/ AD 69-79/ Cross-Quarter 7 Nov/3 Feb Sun Set, LG (-16.2) Fortuna Augusta/ AD 1/ Winter Solstice Sun Set, LG (-22.9) Aesculapius/ 100 BC/ Perseus Rise (β Persei-Algol = +33.0) & Midsummer Moon Major Stand Still Set, LG (-28.1) Isis/ 100 BC/ Midwinter Moon Major Stand Still Rise, Tangent (+28.5) & Equinox Sun Set, Tangent (-0.3) Jupiter/ 150 BC/ Θ Scorpionis-Sargas Rise (-38.0) Apollo/ 550 (rebuilt 70 BC)/ α Columbae-Phact Rise (-37.1) Venus/ 150 BC (rebuilt 70 BC)/ α Columbae-Phact Rise (-37

  2. Lost in the Dark: A proto-history of dark matter

    Science.gov (United States)

    Trimble, Virginia L.; History 1

    2016-01-01

    The Greeks were probably not the first to think of everything, but they were quite often the first to write about it. Thus the first dark matter candidate was the counter-earth of Philolaus (c. 460 BCE), with its illuminated face forever turned away from us. The eclipsing binary interpretation of Algol brought forward the idea (Pigott & Goodricke 1780s) of stars not yet lit up, while the incorporation of thermodynamics into the astronomical tool kit suggested dark, dead stars. Jeans reported a number for these about three times the number of illuminated stars in 1922, the same year that Kapteyn set a comparable limit to what he called dark matter. The phrase appears as an index item in Russell et al.'s 1927 Astronomy and cannot, therefore, have been invented any later. The first extragalactic investigation seems to have been that by Knut Lundmark, writing in German in the Meddelande of the Lund Observatory in 1930. One of the columns of his Tabelle 4 is headed: (Leuchtende + dunkle Materia)/(Leuchtende Materie) and lists values from six up to 100 for six galaxies, e.g. Messier 51 (10), Andromedanebel (20), and NGC 4594 (30). Binary galaxies came from Holmberg (1937), Virgo from Sinclair Smith (1936), and flat rotation curves from Babcock (1939, Andromeda) and Oort (1940, NGC 3115), the latter writing cautiously that the distribution of mass seemed to be very different from that of the light. Then there was a war, but by the time of a 1961 symposium in Santa Barbara focused on the large velocity dispersions in clusters of galaxies, the votes for dark matter slightly outnumbered those for unbound clusters and other alternatives. The idea of a constant of gravity increasing with distance came a smidge later from Arigo Finzi in 1963. The tipping point was arguably 1974 with a pair of short papers summarizing M/L ratios vs. distance scale (which could, of course, have been plotted before WWII). I mention only the slightly earlier and much less often cited one by Einasto

  3. Exploring the Variable Sky with the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Sesar, Branimir; Ivezic, Zeljko; Lupton, Robert; Juric, Mario; Gunn, James; Knapp, Gillian; De Lee, Nathan; Smith, J. Allyn; Miknaitis,Gajus; Lin, Huan; Tucker, Douglas; Doi, Mamoru; Tanaka, Masayuki; Fukugita, Masataka; Holtzman, Jon; Kent, Steve; Yanny, Brian; Schlegel,David; Finkbeiner, Douglas; Padmanabhan, Nikhil; Rockosi, Constance; Bond, Nicholas; Lee, Brian; Stoughton, Chris; Jester, Sebastian; Harris,Hugh; Harding, Paul; Brinkmann, Jon; Schneider, Donald; York, Donald; Richmond, Michael; Vanden Berk, Daniel

    2007-04-01

    We quantify the variability of faint unresolved optical sources using a catalog based on multiple SDSS imaging observations. The catalog covers SDSS Stripe 82, which lies along the celestial equator in the Southern Galactic Hemisphere (22h 24m < {alpha}{sub J2000} < 04h 08m, -1.27{sup o} < {delta}{sub J2000} < +1.27{sup o}, {approx} 290 deg{sup 2}), and contains 58 million photometric observations in the SDSS ugriz system for 1.4 million unresolved sources that were observed at least 4 times in each of the gri bands (with a median of 10 observations obtained over {approx}5 years). In each photometric bandpass we compute various low-order lightcurve statistics such as root-mean-square scatter (rms), {chi}{sup 2} per degree of freedom, skewness, minimum and maximum magnitude, and use them to select and study variable sources. We find that 2% of unresolved optical sources brighter than g = 20.5 appear variable at the 0.05 mag level (rms) simultaneously in the g and r bands. The majority (2/3) of these variable sources are low-redshift (< 2) quasars, although they represent only 2% of all sources in the adopted flux-limited sample. We find that at least 90% of quasars are variable at the 0.03 mag level (rms) and confirm that variability is as good a method for finding low-redshift quasars as is the UV excess color selection (at high Galactic latitudes). We analyze the distribution of lightcurve skewness for quasars and find that is centered on zero. We find that about 1/4 of the variable stars are RR Lyrae stars, and that only 0.5% of stars from the main stellar locus are variable at the 0.05 mag level. The distribution of lightcurve skewness in the g-r vs. u-g color-color diagram on the main stellar locus is found to be bimodal (with one mode consistent with Algol-like behavior). Using over six hundred RR Lyrae stars, we demonstrate rich halo substructure out to distances of 100 kpc. We extrapolate these results to expected performance by the Large Synoptic Survey

  4. Alpha Com eclipse observing campaign

    Science.gov (United States)

    Waagen, Elizabeth O.

    2014-12-01

    Drs. Matthew W. Muterspaugh and Gregory W. Henry (Tennessee State University) have requested AAVSO observers' ssistance in monitoring the possible Algol-like binary star alpha Com before, during, and after the eclipse they have predicted for mid-to-late January 2015. The PIs will be using the Fairborn Observatory automated photometric telescopes on Mt. Hopkins, but they are requesting additional observations not only to supplement theirs but also specifically to have good coverage in the event of bad weather at Mt. Hopkins. Alf Com has a 26-year period and is 4.32V at maximum. The expected amplitude of the eclipse is about 0.8 magnitude and the duration somewhere between 28 and 45 hours. The eclipse is predicted for January 25 ± three days (JD 2457047 ± 3). Muterspaugh at al. first calculated the possibility of a 2015 eclipse in 2010 (AJ). Muterspaugh and Henry recently published an article with updated information (arXiv 2014). V and/or R photometry (other bands welcome) is requested, with a minimal cadence of one measurement/2 hours, to make sure the eclipse is caught right as it begins and to ensure having multiple data points on any unseen objects that might eclipse as well. During eclipse, continuous observations are important. Infrared (H-band) observations could be interesting, should the CHARA array image the event. The precision photometry in the weeks before and after the eclipse is requested in order to catch possible evidence for planets or other materials around the eclipsing star. Updated astrometry from the current epoch would greatly improve the eclipse preductions. Charts with comparison star sequence for alf Com may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). The PIs recommend using the comparison stars HD 113848 (39 Com, HR 4946, HIP 63948, V=5.990, B-V=0.39, F4V) and HD 114520 (HIP 64312, V=6.820, B-V=0.46,F2II). Observations should be submitted to the AAVSO International Database. See AAVSO Alert Notice 506

  5. Preliminary Studies of Interacting Binaries From NURO Observations : V963 Cygni and GSC 1419 0091

    Science.gov (United States)

    Samec, R. G.; Jones, S. M.; Scott, T.; Branning, J.; Miller, J.; Faulkner, D. R.; Hawkins, N. C.

    2005-12-01

    We present preliminary analyses of V963 and V965 Cygni based on observations taken at the National Undergraduate Research Observatory (NURO). Our CCD observations were taken 07-12 March 2005 and 19-25 July 2004 by DRF,RGS, and NCH with the Lowell Observatory 31-inch reflector. Standard UBVRI filters were used. Preliminary light curve analyses and updated periodicity studies are presented for these variables. V963 Cyg (GSC 2656 1995,α (2000) = 19h 44m 04.92s, δ (2000) = +31 41 50.17) is a detached binary discovered by Wachmann (Ast Abh Ham St VI, #1, 1961). The eclipse depths are nearly equal, 0.78 and 0.67 magnitudes in in V in the primary and secondary eclipses, respectively, causing observers to MISTAKINGLY classify it as an Algol-type system. Thus the two stars are similar in temperature and the period has to be DOUBLED. The curves appear fairlysymmetrical with a depressed section following the primary eclipse in R and I about 0.2 phase units wide. In BVRI, 100 to 130 observations were taken along with 75 in U. We determined three new times of minimum light, two secondary eclipses, HJD Min II = 2453207.76857±0.00029d and 2453211.9540±0.0032d, and one primary eclipse HJD Min I = 2453209.86073±0.00095d. A corrected period and an improved ephemeris was computed using available times of minimum light: HJD Min I = 2453209.8616(±0.0011)d + 1.39466792(±0.00000019)*E. GSC 1419 0091 (Brh V132) [α (2000) = 10h 11m 59.152s,δ (2000) = +16 52 30.28] is an overcontact binary discovered by Klaus Bernhard (BAV, http://www.var-mo.de/star/brh_v132.htm). We took approximately 60-65 observations in each of B,V,R, and I. We determined four new times of minimum light: HJD Min I = 2453437.8293(±0.0003) and 2453441.8291(±0.0019), and HJD Min II = 2453437.6973(±0.0012) and 2453442.76317(±0.0005). We computed an improved ephemeris from all available times of minimum and low light: HJD Min I = 2452754.4733(±0.0030)d + 0.2667251*E(±0.0000011). The light curves show shallow

  6. Light curve solutions and study of roles of magnetic fields in period variations of the UV Leo system

    Directory of Open Access Journals (Sweden)

    D Manzoori

    2009-12-01

    Full Text Available The solutions of photometric BV light curves for the Algol like system UV Leo were obtained using Wilson-Devinney code. The physical and orbital parameters along with absolute dimensions of the system were determined. It has been found that to best fit the V light curve of the system, assumptions of three dark spots were necessary two on the secondary and one on the primary. The absolute visual magnitudes (Mv of the individual components i.e., primary and secondary were estimated to 4.41 and 4.43, respectively, through the color curve analysis. The period analysis of the system presented elsewhere, indicated a cyclic period change of 12 yr duration, which was attributed to magnetic activity cycle, as a main cause of period variation in the system, through the Applegate mechanism. To verify the Applegate model I preformed calculations of some related parameters barrowed from Apllegate and Kalimeris. Values of all the calculated parameters were in accordance to those obtained for similar systems by Applegate. The differential magnitudes Δ B and Δ V, along with corresponding values of Δ(B-V color index. The cyclic variations in brightness are quite clear. There are three predictions of Applegate's theory concerning effects of cyclic magnetic changes on the period variations, which can be checked through the observations, these are as follows: I The long term variations in mean brightness (at outside of eclipses and cyclic changes of orbital period, vary with the same period. II The active star gets bluer as it gets brightened and/or the brightness and color variations are to be in phase. III Changes in luminosity due to changes in quadrupole moment should be of the order 0.1 mag. All the above mentioned predictions of Applegate’s theory are verified. These results combined with cyclic character of P(E presented elsewhere and also consistency of parameters which are obtained in this paper, led me to conclude that one the main causes of period

  7. 云南天文台2000年度学术论文汇总

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@一、发表论文 1、 SCI(科学引文索引)类论文 1) 一个日珥D3线的特征和计算=Calculations and physical properties of the D3 emission lines of a prominence.李可军,顾啸马,陈学昆.MNRAS,2000,Vol.313,761-766. 2) 两个相接双星TZ Boo和Y Sex的轨道周期研究=Orbital period Studies of the two contact binaries TZ Bootis and Y Sextantis.钱声邦,刘清耀.A&A,2000,Vol.355,171-175. 3) 1998年在云南的狮子座流星雨目视观测=Visual observations of the leonid meteors 1998 in Yunnan.吴光节,张周生.Earth,Moon,and Planets,2000,Vol.81,No.3,193-200. 4) 微波弱偏振尖峰的观测特征=Observational characteristics of weak polarized microwave spikes.汪敏,傅其骏,谢瑞祥,黄光力.Solar Physics,1999,Vol.189,331-344. 5) 重联对日冕物质抛射过程的影响=Effects of reconnection on the coronal mass ejection process.林隽,Forbes T.G. Journal of Geophysical Research ,2000,Vol.105,No.A2,2375-2392. 6) 正至冷却的相对论电子模拟=Simulation of Gamma-Ray bursts from cooling relativistic electrons.王建成,岑学奋,钱铜铃,许骏,汪从云.ApJ,2000,Vol.532,267-272. 7) 非同步转动双星系统的演化=Evolution of non-synchronized binary systems.黄润乾,曾艺蓉.中国科学(A辑),2000,Vol.30,No.2,187. 8) 21周太阳活动真的是南占优吗?=Does the southern dominance of solar activity really exist in solar cycle 21.李可军,顾啸马.A&A,2000,Vol.353,396. 9) 湍流对太阳P-模振荡的影响=The influence of turbulence on the solar P-mode oscillations.毕少兰,许华 .A&A,2000,Vol.357,330-336. 10) Algol型双星可能的质量和角动量损失=Possible mass and angular momentum loss in Algol-type binaries.II TT Del Bo Mon and Y Psc.钱声邦.AJ,2000,Vol.119,3064.

  8. Implications of the Turing machine model of computation for processor and programming language design

    Science.gov (United States)

    Hunter, Geoffrey

    2004-01-01

    ; it may be allocated as its execution commences, and deallocated as its execution terminates, and if the amount of this local memory is not known until just before execution commencement, then it is essential that it be allocated dynamically as the first action of its execution. This dynamically allocated/deallocated storage of each subprogram"s intermediate values, conforms with the stack discipline; i.e. last allocated = first to be deallocated, an incidental benefit of which is automatic overlaying of variables. This stack-based dynamic memory allocation was a semantic implication of the nested block structure that originated in the ALGOL-60 programming language. AGLOL-60 was a TM language, because the amount of memory allocated on subprogram (block/procedure) entry (for arrays, etc) was computable at execution time. A more general requirement of a Turing machine process is for code generation at run-time; this mandates access to the source language processor (compiler/interpretor) during execution of the process. This fundamental aspect of computer science is important to the future of system design, because it has been overlooked throughout the 55 years since modern computing began in 1048. The popular computer systems of this first half-century of computing were constrained by compile-time (or even operating system boot-time) memory allocation, and were thus limited to executing FA processes. The practical effect was that the distinction between the data-invariant program and its variable data was blurred; programmers had to make trial and error executions, modifying the program"s compile-time constants (array dimensions) to iterate towards the values required at run-time by the data being processed. This era of trial and error computing still persists; it pervades the culture of current (2003) computing practice.

  9. Numerical Recipes in C++: The Art of Scientific Computing (2nd edn). Numerical Recipes Example Book (C++) (2nd edn). Numerical Recipes Multi-Language Code CD ROM with LINUX or UNIX Single-Screen License Revised Version

    International Nuclear Information System (INIS)

    (C++), the authors point out some of the problems in the use of C++ in scientific computing. I have not found any mention of parallel computing in NR(C++). Fortran has quite a lot going for it. As someone who has used it in most of its versions from Fortran II, I have seen it develop and leave behind other languages promoted by various enthusiasts: who now uses Algol or Pascal? I think it unlikely that C++ will disappear: it was devised as a systems language, and can also be used for other purposes such as scientific computing. It is possible that Fortran will disappear, but Fortran has the strengths that it can develop, that there are extensive Fortran subroutine libraries, and that it has been developed for parallel computing. To argue with programmers as to which is the best language to use is sterile. If you wish to use C++, then buy NR(C++), but you should also look at volume 2 of NR(F). If you are a Fortran programmer, then make sure you have NR(F), volumes 1 and 2. But whichever language you use, make sure you have one version or the other, and the CD ROM. The Example Book provides listings of complete programs to run nearly all the routines in NR, frequently based on cases where an analytical solution is available. It is helpful when developing a new program incorporating an unfamiliar routine to see that routine actually working, and this is what the programs in the Example Book achieve. I started teaching computational physics before Numerical Recipes was published. If I were starting again, I would make heavy use of both The Art of Scientific Computing and of the Example Book. Every computational physics teaching laboratory should have both volumes: the programs in the Example Book are included on the CD ROM, but the extra commentary in the book itself is of considerable value. (book review: Press, William H; Teukolsky, Saul A; Vettering, William T; Flannery, Brian P - ISBN 0-521-75034-4; ISBN 0-521-75034-2; ISBN 0-521-75036-9)