WorldWideScience

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. UXOR Hunting among Algol Variables

    Science.gov (United States)

    Poxon, M.

    2015-06-01

    The class of variable typified by UX Orionis (UXORs or UXors) are young stars characterised by aperiodic or semiperiodic fades from maximum. This has led to several of the class being formerly catalogued as Algol-type eclipsing binaries (EAs), which can show superficially similar light variations. With this in view, I propose a campaign to search for more UX Ori type stars.

  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. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. [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

  13. 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...

  14. From the Heart of The Ghoul: C and N Abundances in the Corona of Algol B

    CERN Document Server

    Drake, J J

    2003-01-01

    Chandra Low Energy Transmission Grating Spectrograph observations of Algol have been used to determine the abundances of C and N in the secondary star for the first time. The analysis was performed relative to similar observations of an adopted "standard" star HR 1099. It is demonstrated that HR 1099 and Algol are coronal twins in many respects and that their X-ray spectra are very similar in nearly all details, except for the observed strengths of C and N lines. The H-like transitions of C and N in the coronae of Algol and HR 1099 demonstrate that the surface abundances of Algol B have been strongly modified by CN-processing, as shown earlier by Schmitt & Ness (2002). It is found that N is enhanced in Algol B by a factor of 3 compared to HR 1099. No C lines are detected in the Algol spectrum, indicating a C depletion relative to HR 1099 by a factor of 10 or more. These C and N abundances indicate that Algol B must have lost at least half of its initial mass, and are consistent with predictions of evoluti...

  15. Cyclic period changes in the algol ww cygni

    Directory of Open Access Journals (Sweden)

    R. T. Zavala

    2004-01-01

    Full Text Available Se han observado variaciones c clicas del per odo en muchas clases de binarias cercanas con una duraci on comprendida entre un a~no y una d ecada. WW Cygni, la binaria tipo Algol, presenta una variaci on c clica en su per odo orbital con una amplitud de algo m as de 0.02 d as y un per odo de 56 a~nos. Un tercer o cuarto cuerpo hipot etico no explica satisfactoriamente esta variaci on observada en su per odo orbital. Las variaciones en luminosidad y color del sistema en el m nimo primario del eclipse concuerdan con el modelo propuesto por Applegate para variaciones de per odo inducidas por el ciclo magn etico en WW Cygni. Hemos comenzado a realizar una serie de observaciones de 9 binarias cercanas para buscar evidencias de variaciones en luminosidad y color consistentes con la hip otesis del ciclo magn etico. Se sugiere Librae como un caso apropiado para realizar observaciones con un interfer ometro optico con el n de veri car la hip otesis del tercer cuerpo propuesta para este sistema tipo Algol.

  16. 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...

  17. A comprehensive study of six Algol type binaries

    CERN Document Server

    Liakos, Alexios; Niarchos, Panagiotis

    2014-01-01

    CCD light curves of the Algol type eclipsing binaries DP Cep, AL Gem, FG Gem, UU Leo, CF Tau and AW Vul were analysed using the Wilson-Deninney code and new geometric and absolute parameters were derived. Due to cyclic apparent orbital period changes of the systems, probably caused by the Light-Time Effect, the contribution of a third light was taken into account in the light curve solution. All the reliable timings of minima found in the literature were used to study the period variations and search for the presence of a tertiary component in the systems. A comparison between the parameters of the third body derived from the light curve and orbital period analyses is also discussed. Moreover, the absolute parameters of the eclipsing binary components were also used to determine their current evolutionary state.

  18. A comprehensive study of six Algol type binaries

    Science.gov (United States)

    Liakos, A.; Zasche, P.; Niarchos, P.

    2011-12-01

    CCD light curves of the Algol type eclipsing binaries DP Cep, AL Gem, FG Gem, UU Leo, CF Tau and AW Vul were analysed using the Wilson-Devinney code and new geometric and absolute parameters were derived. Due to cyclic apparent orbital period changes of the systems, probably caused by the Light-Time Effect, the contribution of a third light was taken into account in the light curve solution. All the reliable timings of minima found in the literature were used to study the period variations and search for the presence of a tertiary component in the systems. A comparison between the parameters of the third body derived from the light curve and orbital period analyses is also discussed. Moreover, the absolute parameters of the eclipsing binary components were also used to determine their current evolutionary state.

  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. Interacting Binary Star Environments and the W Ser - DPV - Algol Connection

    CERN Document Server

    Mennickent, R E

    2009-01-01

    Recent work on some kinds of interacting binaries is summarized, with emphasis on Cataclysmic Variables, Algol-like variables and the recently discovered Double Periodic Variables (DPVs). The sequence W Serpentids (very massive with irregular variability and large mass loss) $\\to$ DPVs (less massive with regular variability and ciclic mass loss) $\\to$ Algols (even less massive with small mass loss) could correspond to an evolutionary sequence, and illustrate the importance of the mass transfer rate in shaping observable and mass loss properties for these systems.

  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. 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 ...

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

    Science.gov (United States)

    Jetsu, Lauri; Porceddu, Sebastien

    2015-12-01

    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 lucky for Heaven and for Earth. Now, for the first time, periodicity is discovered in the descriptions of the days in CC. Unlike many previous attempts to uncover the reasoning behind the myths of individual days, we discover the actual rules in the appearance and behaviour of deities during the whole year.

  5. 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 $\\...

  6. 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.

  7. Short period light variation of the Algol-type binary U Coronae Borealis

    Science.gov (United States)

    Narusawa, Shin-Ya; Waki, Yoshifumi; Ioroi, Masayuki; Nakamura, Yasuhisa; Takeuti, Mine

    The short period variability in the light curve of U CrB, an Algol-type binary, was examined with the published data of van Gent (1989). The period of variability was approximately 0.05 d and the amplitude was 0.05 mag. The superposition of several modes was suggested. The properties of the light variability were compared with those of the early-type main-sequence pulsating stars.

  8. Photometric Properties for Selected Algol-type Binaries. V. V1241 Tauri

    Science.gov (United States)

    Yang, Y.-G.; Zhang, X.-B.; Li, H.-L.; Dai, H.-F.

    2012-11-01

    We present new photometry for the eclipsing binary V1241 Tau, which was obtained on six nights between 2011 December and 2012 January using the 85 cm telescope at the Xinglong station of the National Astronomical Observatories of China. By using the updated Wilson-Devinney code, photometric models with third lights were deduced from two sets of light curves. The result implies that V1241 Tau is an Algol-type near-contact binary (NCB), whose mass ratio and filling-out of the primary are q = 0.545 (± 0.003) and f 1 = 82.4% (± 0.2%), respectively. Based on all available times of minimum light spanning over 80 yr, the O - C curve of V1241 Tau appears to show a quasi-sinusoidal oscillation, i.e., a light-time orbit. The modulated period and amplitude are P mod = 47.4 (± 1.7) yr and A = 0.0087 (± 0.0005) days, respectively. This kind of period variation may be more likely attributed to the light-time effect via a presence of an unseen third body. From an analysis of 23 Algol-type NCBs with EB-type light curves, we determine that the fill-out for the primary f 1 will increase as the orbital period P decreases. With angular momentum loss, the orbit of the binary will shrink, which causes f 1 to increase. The primary component finally fills its Roche lobe, and the binary evolves into contact configuration. Therefore, this kind of Algol-type NCB with EB-type light curves, such as V1241 Tau, may be a progenitor of the A-type W UMa binary.

  9. A Hot Spot and Mass Transfer of the Algol-type Binary System WZ Crv

    CERN Document Server

    Virnina, Natalia A; Mogorean, Maxim V

    2011-01-01

    We present the results of two color VR observation of the Algol-type binary system WZ Crv (12h44m15.19s, -21d25m35.4s) which were obtained using the remotely controlled telescope TOA-150 of Tzec Maun Observatory. We determined the moments of individual minima, the orbital period and its derivative, the initial epoch, color indices V-R and temperature estimates of the components. Also we noticed that the phase curve is asymmetric: the second maximum is higher than the first one. It indicates that there is a spot in the photosphere of one of the stars in this system.

  10. The Algol-Type Eclipsing Binary X Tri: BVRI modeling and O-C Diagram Analysis

    Science.gov (United States)

    Liakos, A.; Zasche, P.; Niarchos, P.

    2010-12-01

    CCD photometric observations of the Algol-type eclipsing binary X Tri have been obtained. The light curves are analyzed with the Wilson-Devinney (WD) code and new geometric and photometric elements are derived. A new O-C analysis of the system, based on the most reliable timings of minima found in the literature, is presented and apparent period changes are discussed with respect to possible and multiple Light-Time Effect (LITE) in the system. Moreover, the results for the existence of additional bodies around the eclipsing pair, derived from the period study, are compared with those for extra luminosity, derived from the light curve analysis.

  11. The Algol type eclipsing binary X Tri: BVRI modelling and O-C diagram analysis

    CERN Document Server

    Liakos, A; Niarchos, P

    2009-01-01

    CCD photometric observations of the Algol-type eclipsing binary X Tri have been obtained. The light curves are analyzed with the Wilson-Devinney (WD) code and new geometric and photometric elements are derived. A new O-C analysis of the system, based on the most reliable timings of minima found in the literature, is presented and apparent period changes are discussed with respect to possible and multiple Light-Time Effect (LITE) in the system. Moreover, the results for the existence of additional bodies around the eclipsing pair, derived from the period study, are compared with those for extra luminosity, derived from the light curve analysis.

  12. 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...

  13. TZ Lyrae: an Algol-type Eclipsing Binary with Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    Yuan-Gui Yang; Xin-Guo Yin

    2007-01-01

    We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt =+7.18 × 10-8d yr-1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dm = +2.21 × 10-8M⊙ yr-1. The cyclic component, with a period of P3= 45.5 yr and an amplitude of A = 0d.0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components.Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyf is an Algol-type eclipsing binary with a mass ratio of q = 0.297(±0.003). The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.

  14. TZ Lyrae: an Algol-type Eclipsing Binary with Mass Transfer

    Science.gov (United States)

    Yang, Yuan-Gui; Yin, Xin-Guo

    2007-04-01

    We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt=+7.18× 10^{-8} d yr^{-1}, indicating that a mass transfer from the less massive component to the more massive one at a rate of dm=+2.21×10^{-8} M_⊙ yr^{-1}. The cyclic component, with a period of P_{3}=45.5 yr and an amplitude of A=0.0040°, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q=0.297(±0.003). The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.

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

    Science.gov (United States)

    Yang, Yuan-Gui

    2013-12-01

    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.

  16. 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.

  17. 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...

  18. 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.

  19. Three-Dimensional Hydrodynamic Simulations of Accretion in Short Period Algols

    CERN Document Server

    Raymer, Eric

    2012-01-01

    Recent observations have shown that the direct-impact Algol systems U CrB and RS Vul possess gas located outside of the orbital plane, including a tilted accretion disc in U CrB. Observations of circumstellar gas surrounding the mass donor in RS Vul suggest magnetic effects could be responsible for deflecting the accretion stream out of the orbital plane, resulting in a tilted disc. To determine whether a tilted disc is possible due to a deflected stream, we use three-dimensional hydrodynamic simulations of the mass transfer process in RS Vul. By deflecting the stream 45 degrees out of the orbital plane and boosting the magnitude of the stream's velocity to Mach 30, we mimic the effects of magnetic activity near L1. We find that the modified stream parameters change the direct-impact nature of the system. The stream misses the surface of the star, and a slightly warped accretion disc forms with no more than 3 degrees of disc tilt. The stream-disc interaction for the deflected stream forces a large degree of m...

  20. Photometric Properties for Selected Algol-type Binaries. IV. AV Hydrae and DZ Cassiopeiae

    Science.gov (United States)

    Yang, Y.-G.; Li, L.-H.; Dai, H.-F.

    2012-08-01

    We present BVR photometric observations and several eclipsing times for AV Hya and DZ Cas from 2004 to 2011. Using the Wilson-Devinney method, the photometric solutions with hot spots were deduced from their asymmetric light curves. The results indicate that both stars are Algol-type binaries, whose mass ratio, q ph, and fill-out factor of the primary, f 1, are q ph = 0.255(± 0.002) and f 1 = 81.2(± 0.2)% for AV Hya, and q ph = 0.093(± 0.003) and f 1 = 98.7(± 0.3)% for DZ Cas. Based on all available light minimum times, it is discovered that the O - C curve of each star could be described by a light-time orbit overlying on a downward parabola. Their periods and amplitudes are P 3 = 37.2(± 0.7) yr and A = 0fd0095(±0fd0006) for AV Hya, and P 3 = 62.5(± 1.0) yr and A = 0fd0183(±0fd0007) for DZ Cas. Cyclic variations may result from the light-time effect due to the third body. The secular period decrease rates are dP/dt = -1.47(± 0.04) × 10-7 days yr-1 for AV Hya and dP/dt = -0.92(± 0.04) × 10-7 days yr-1 for DZ Cas. This may be interpreted using mass and angular momentum loss from the system. With decreasing period, the fill-out factor of the primary increases and it may finally fill its inner Roche lobe. Therefore, AV Hya and DZ Cas with a secular period decrease will evolve from semi-detached configurations into contact ones.

  1. Optical photometry and X-ray monitoring of the "Cool Algol" BD+05 706 Determination of the physical properties

    CERN Document Server

    Torres, G; Marschall, L A; Neuhäuser, R; Duffy, A S; Torres, Guillermo; Mader, Jeff A.; Marschall, Laurence A.; Neuhaeuser, Ralph; Duffy, Alaine S.

    2003-01-01

    We present new photometric observations in the BVRI bands of the double-lined eclipsing binary BD+05 706 conducted over three observing seasons, as well as new X-ray observations obtained with the ROSAT satellite covering a full orbital cycle (P = 18.9 days). A detailed light-curve analysis of the optical data shows the system to be semidetached, confirming indications from an earlier analysis by Torres et al. (1998), with the less massive and cooler star filling its Roche lobe. The system is a member of the rare class of cool Algol systems, which are different from the "classical" Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the new photometry with a reanalysis of the spectroscopic observations reported by Torres et al. (1998) we derive accurate absolute masses for the components of M1 = 2.633 +/- 0.028 Msun and M2 = 0.5412 +/- 0.0093 Msun, radii of R1 = 7.55 +/- 0.20 Rsun and R2 = 11.02 +/- 0.21 Rsun, as well as effective temperature...

  2. 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.

  3. LUT REVEALS AN ALGOL-TYPE ECLIPSING BINARY WITH THREE ADDITIONAL STELLAR COMPANIONS IN A MULTIPLE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L.-Y.; Zhou, X.; Qian, S.-B.; Li, L.-J.; Liao, W.-P.; Tian, X.-M.; Wang, Z.-H. [Yunnan Observatories, Chinese Academy of Sciences (CAS), P.O. Box 110, 650011 Kunming (China); Hu, J.-Y., E-mail: zhuly@ynao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing (China)

    2016-04-15

    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{sub ⊙}. 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.

  4. 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.

  5. THE FIRST PHOTOMETRIC ANALYSES OF THE ALGOL BINARY SYSTEMS GSC 04328-02164 AND GSC 03164-01558

    Energy Technology Data Exchange (ETDEWEB)

    Essam, A.; Hamed, Amal S.; Mohamadien, Ghada F. [National Research Institute of Astronomy and Geophysics, 11421 Helwan, Cairo (Egypt); Youssef, Shahenaz M., E-mail: essam60@yahoo.com [Astronomy Department, Faculty of Science, Cairo University, Cairo (Egypt)

    2016-01-15

    The CCD observations for the eclipsing Algol type binary systems GSC 04328-02164 in wideband BVR{sub c}I{sub c} filters and GSC 03164-01558 in B and I filters have been analyzed using the PHOEBE package (v 0.31a) to determine their orbital and physical parameters. The absolute parameters and evolutionary tracks of the two systems have been determined. The results show that the mass ratio, inclination, distance, and age for the system GSC 04328-02164 are equal to q = 0.674 ± 0.002, i = 75.997 ± 0.022, d = 375.477 ± 4.299 pc, and τ = 26.76 ± 15.65 ∗ 10{sup 8} years, respectively. For the other system, GSC 03164-01558, q = 0.941 ± 0.006, i = 88.0484 ± 0.030, d = 444.651 ± 9.444 pc, and τ = 53.63 ± 9.16 ∗ 10{sup 8} years.

  6. A Spectroscopic Study of the Algol-type Binaries S Equulei and KO Aquilae: Absolute Parameters and Mass Transfer

    CERN Document Server

    Soydugan, F; Soydugan, E; Catalano, S; Demircan, O; Ibanoglu, C

    2007-01-01

    We present and analyze high-resolution optical spectra of the Algol binaries S Equ and KO Aql. New accurate radial velocities for the hotter primary components are obtained. Thanks to the cross-correlation procedure, we were able to measure, for the first time to our knowledge, radial velocities also for the cool secondary components of S Equ and KO Aql. By combining the parameters obtained from the solution of the radial velocity curves with those obtained from the light curve analysis, reliable absolute parameters of the systems have been derived. The rotational velocity of the hotter components of S Equ and KO Aql has been measured and it is found that the gainers of both systems rotate about 30 % faster than synchronously. This is likely due to mass transfer across the Lagrangian L1 point from the cooler to the hotter component. The lower luminosity of the mass-gaining components of these systems compared to normal main-sequence stars of the same mass can be also an effect of the mass transfer. The H-alph...

  7. 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.

  8. 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.

  9. 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.

  10. Photometric Properties for Selected Algol-type Binaries. VIII. The Triple Systems DI Peg and AF Gem Revisited

    Science.gov (United States)

    Yang, Yuan-Gui; Yang, Ying; Li, Shu-Zheng

    2014-06-01

    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.

  11. Photometric Properties of Selected Algol-type Binaries. III. AL Geminorum and BM Monocerotis with Possible Light-time Orbits

    Science.gov (United States)

    Yang, Y.-G.; Li, H.-L.; Dai, H.-F.

    2012-01-01

    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 ph = 0.090(± 0.005) and f 1 = 47.3%(± 0.3%) for AL Gem, and q ph = 0.275(± 0.007) and f 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 ⊙ for AL Gem and 0.26 M ⊙ 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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.

  16. 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...

  17. Asteroseismic Investigation of two Algol-type systems V1241 Tau and GQ Dra

    CERN Document Server

    Ulaş, Burak; Gazeas, Kosmas; Erkan, Naci; Liakos, Alexios

    2013-01-01

    We present new photometric observations of eclipsing binary systems V1241 Tau and GQ Dra. We use the following methodology: Initially, WD code is applied to the light curves, in order to determine the photometric elements of the systems. Then the residuals are analysed using Fourier Transformation techniques. The results show that one frequency can be barely attributed to the residual light variation of V1241 Tau, while there is no evidence of pulsation on the light curve of GQ Dra.

  18. Photometric Properties for Selected Algol-type Binaries. II. AO Serpentis and V338 Herculis

    Science.gov (United States)

    Yang, Y.-G.; Hu, S.-M.; Guo, D.-F.; Wei, J.-Y.; Dai, H.-F.

    2010-04-01

    We present the first multiband photometry for the semidetached eclipsing binary AO Serpentis, observed on seven nights between 2009 April and July at the Weihai Observatory of Shandong University. By using the 2003 version of the Wilson-Devinney code, the photometric solutions of AO Ser and a similar object V338 Her were (re)deduced. The spectral types and orbital periods are A2 and P = 0.8793 days for AO Ser, F1V and P = 1.3057 days for V338 Her. The results reveal that two binaries are low mass ratio systems, whose secondary components fill their Roche lobes. The fill-out factors of the primary components are f = 58.6% for AO Ser and f = 54.2% for V338 Her, respectively. From the O - C curves of AO Ser and V338 Her, it is discovered that secular period changes with cyclic variations exist. The periods and semiamplitudes are 17.32(±0.01) yr and 0.0051(±0.0001) days for AO Ser, 29.07(±0.04) yr and 0.0116(±0.0015) days for V338 Her, respectively. This kind of cyclic oscillation may be attributed to either the light-time effect via an assumed third body or perhaps cyclic magnetic activity on the secondary component. For AO Ser, the long-term period decreases at a rate of dP/dt = -5.35(±0.03) × 10-7 days yr-1, which may be caused by mass and angular momentum loss from the system. Considering the period decreasing, the fill-out factor of the primary for AO Ser will increase and it will finally fill its Roche lobe. Meanwhile, the secular period increase rate for V338 Her is dP/dt = +1.44(±0.24) × 10-7 days yr-1, indicating that mass transfers from the less massive component to the more massive component. This will also cause the fill-out factor of the primary to increase. When the primaries fill their Roche lobes, AO Ser and V338 Her may evolve into contact stars, as predicted by the theory of thermal relaxation oscillations.

  19. Binarity and Pulsation in Algol-type Binary System SX Draconis

    Science.gov (United States)

    Soydugan, E.; Kaçar, Y.

    2013-04-01

    Photometric observations of SX Dra were carried out to determine the properties of the components and pulsational characteristics of the more massive pulsational component. Physical parameters of the component stars were obtained by modeling B and V light curves using the Wilson-Devinney code. Results indicate that SX Dra is a semi-detached system with the secondary component filling its Roche lobe. The O-C data showed parabolic and sinusoidal variation. Cyclic variation in the O-C diagram could be the result of the possible magnetic activity of the secondary component instead of the third body. The secular increase in the orbital period of the system can be interpreted as being the result of mass transfer from the secondary component to the primary one at a rate of 2.1 × 10-7 M ⊙ yr-1. Results of a time-series analysis performed after removing binary effects indicated that the hot component shows δ Scuti light variations with pulsational periods of 63 and 73 minutes. Spherical harmonic degrees (l) were determined to be 3 for the first frequency and 1-2 for the second frequency.

  20. 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...

  1. 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

    the same block structure and binding structure as in the source program, à la Abdali. The target code uses a control operator in direct style, à la Landin. In fact, the control operator used is almost Landin’s J—hence our title. Our translation thus complements a continuation-passing translation à la...

  2. 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

  3. 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.

  4. 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

  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. 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.)

  7. 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

  8. 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...

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Algorithms over partially ordered sets

    DEFF Research Database (Denmark)

    Baer, Robert M.; Østerby, Ole

    1969-01-01

    in 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....

  16. 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)

  17. 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.

  18. 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.)

  19. NZ Ser: the results of the analysis of the 25 years photometric activity

    Science.gov (United States)

    Barsunova, O.; Mel'nikov, S.; Grinin, V.; Katysheva, N.; Shugarov, S.

    2014-03-01

    We present the analysis of the long-term photometric variability of NZ Ser. The object shows both large-scale cyclic variability and low-amplitude Algol-like, fading typical for UX Ori stars. The variations of the stellar brightness are accompanied by variations of the B-V and V-R colors: when the brightness decreases, B-V decreases, while V-R increases.

  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. 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...

  2. 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 ...

  3. 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.

  4. Modeling Gyrosynchrotron Coronae of Radio-Loud Stars

    Science.gov (United States)

    Peterson, William M.

    2015-01-01

    Fast gyrosynchrotron codes are used to model the emission in close, active binary star systems. Multiple magnetic field topologies, plasma densities, and scale heights for the emitting plasma are tested for in an attempt to duplicate the emission characteristics detected using high-resolution VLBI imaging of the close active binaries UX Arietis and Algol. Also included are effects of occlusion by the companion star. It is found that a co-orbiting coronal loop oriented toward the companion star with its feet anchored on the poles of the active star is consistent with the observed emission from these two radio-loud stars.

  5. 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...

  6. 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 has...

  7. 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)

  8. 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.

  9. Parallel computations in linear algebra. II

    Energy Technology Data Exchange (ETDEWEB)

    Faddeeva, V.N.; Faddeev, D.K.

    1982-05-01

    For pt.I, see Kibernetika, vol.13, no.6, p.28 (1977). Considerable effort was devoted in the surveyed period to automatic decomposition of sequential algorithms, or rather of procedures or subprograms written in the algorithmic languages ALGOL or FORTRAN. The authors do not consider this body of research, they only note that, on the one hand, the available linear algebra subprograms included in Eispack provide convenient objects for testing various approaches to automatic construction of parallel programs and, on the other, an important state in this activity is the development of methods for fast and efficient solution of linear recurrences, which reduce to solving systems of linear equations with band-triangular matrix (in particular, of sufficiently small width). This article reflects the penetration of the parallelism ideas into the computational methods of linear algebra in recent years. 74 references.

  10. 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.

  11. 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...

  12. 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.

  13. 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...

  14. A translator and simulator for the Burroughs D machine

    Science.gov (United States)

    Roberts, J.

    1972-01-01

    The D Machine is described as a small user microprogrammable computer designed to be a versatile building block for such diverse functions as: disk file controllers, I/O controllers, and emulators. TRANSLANG is an ALGOL-like language, which allows D Machine users to write microprograms in an English-like format as opposed to creating binary bit pattern maps. The TRANSLANG translator parses TRANSLANG programs into D Machine microinstruction bit patterns which can be executed on the D Machine simulator. In addition to simulation and translation, the two programs also offer several debugging tools, such as: a full set of diagnostic error messages, register dumps, simulated memory dumps, traces on instructions and groups of instructions, and breakpoints.

  15. 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.

  16. 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...

  17. Photometric Analysis and Period Investigation of the EW Type Eclipsing Binary V441 Lac

    Indian Academy of Sciences (India)

    K. Li; S.-M. Hu; D.-F. Guo; Y.-G. Jiang; D.-Y. Gao; X. Chen

    2016-09-01

    Four color light curves of the EW type eclipsing binary V441Lac were presented and analyzed by the W--D code. It is found that V441Lac is an extremely low mass ratio $(q = 0.093 \\pm 0.001)$ semi-detached binary with the less massive secondary component filling the inner Roche lobe. Two dark spots on the primary component were introduced to explain the asymmetric light curves. By analyzing all times of light minimum, we determined that the orbital period of V441 Lac is continuously increasing at a rate of ${\\rm d}P/{\\rm d}t = 5.874(\\pm 0.007)\\times 10^{--7} {\\rm d yr}^{--1}$. The semidetached Algol type configuration of V441 Lac is possibly formed by a contact configuration destroyed shallow contact binary due to mass transfer from the less massive component to the more massive one predicted by the thermal relaxation oscillation theory.

  18. 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).

  19. 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

  20. 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

  1. $\\gamma$ Doradus Pulsations in the Eclipsing Binary Star KIC 6048106

    CERN Document Server

    Lee, Jae Woo

    2016-01-01

    We present the ${\\it Kepler}$ photometry of KIC 6048106 exhibiting O'Connell effect and multiperiodic pulsations. Including a starspot on either of the components, light-curve synthesis indicates that this system is a semi-detached Algol with a mass ratio of 0.211, an orbital inclination of 73.9 deg, and a large temperature difference of 2,534 K. To examine in detail both spot variations and pulsations, we separately analyzed the {\\it Kepler} time-series data at the interval of an orbital period by an iterative way. The results reveal that the variable asymmetries of the light maxima can be interpreted as the changes of a magnetic cool spot on the secondary component with time. Multiple frequency analyses were performed in the outside-eclipse light residuals after removal of the binarity effects from the observed {\\it Kepler} data. We detected 30 frequencies with signal to noise amplitude ratios larger than 4.0, of which six ($f_2$--$f_6$ and $f_{10}$) can be identified as high-order (17 $\\le n \\le$ 25) low-d...

  2. Das Universum der Sterne. Himmelsbeobachtungen und Streifzüge durch die moderne Astronomie.

    Science.gov (United States)

    Rowan-Robinson, M.

    This book is a German translation, by M. Röser, of the English original published in 1990 (see 52.003.046). Contents: 1. Der Halleysche Komet. 2. Alpha Centauri - Der sonnennächste Stern. 3. Sirius und sein Begleiter, ein Weißer Zwerg. 4. Polaris - Der Polarstern. 5. Wega - Ein Planetensystem im Entstehen? 6. Mira - Der erste bekannte veränderliche Stern. 7. Der Ring-Nebel - "Todeskampf" eines sonnenähnlichen Sterns. 8. Der Orion-Nebel - Die Geburt neuer Sterne. 9. Delta Cephei - Die Meßlatte des Weltalls. 10. Algol - Der Teufelsstern. 11. Nova Aquilae - Der neue Stern von 1918. 12. Der Krebs-Nebel - Die Supernova des Jahres 1054. 13. Die Hyaden und Plejaden - Sternhaufen. 14. Die Milchstraße - Unsere Galaxis. 15. Die Magellanschen Wolken - Unsere Nachbarn im Weltall. 16. Der Andromeda-Nebel - Zwilling unserer Galaxis. 17. Messier 87 - Eine Radiogalaxie. 18. 3C 273 - Rätselhafter Quasar. 19. Messier 82 - Eine "Starburst"-Galaxie. 20. Der Virgo-Haufen - Ein reicher Galaxienhaufen. 21. Das Universum.

  3. Complex Analysis of the Stellar Binary V446\\,Cep; A New Massive Eclipsing Binary in Cepheus\\,OB2 Association

    CERN Document Server

    Cakirli, O; Sipahi, E; Frasca, A; Catanzaro, G

    2014-01-01

    We present new spectroscopic observations of the early type, double-lined eclipsing binary V446\\,Cep. The radial velocities and the photometric data obtained by $Hipparcos$ were analysed for deriving the astrophysical parameters of the components. Masses and radii were determined as M$_p$=17.94$\\pm$1.16 M$_{\\odot}$ and R$_p$=8.33$\\pm$0.29 R$_{\\odot}$, M$_s$=2.64$\\pm$0.30 M$_{\\odot}$ and R$_s$=2.13$\\pm$0.10 R$_{\\odot}$ for the components of V446\\,Cep. Our analyses show that V446\\,Cep is a detached Algol-type system. Based on the position of the components plotted on the theoretical Hertzsprung-Russell diagram, we estimate that the age of V446\\,Cep is about 10 Myr, neglecting the effects of mass-loss and mass exchange between the components. Using the UBVJHK magnitudes and interstellar absorption we estimated the mean distance to the system V446\\,Cep as 1100$\\pm$62\\,pc.

  4. 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...

  5. 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.

  6. 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.

  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. 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_...

  9. 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...

  10. Period studies and photometric models for two EB-type binaries EU Hya and AW Vul

    Science.gov (United States)

    Yang, Yuan-Gui; Li, Qun; Li, Hua-Li; Dai, Hai-Feng

    2016-02-01

    New photometry for two Algol-type binaries, EU Hya (P = 0.7782 d) and AW Vul (P = 0.8065 d), was carried out using the 60-cm telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, photometric elements were derived from the multi-color light curves. The modeled results indicate that the two systems are near-contact binaries, whose secondary components fill their Roche lobes. The fill-out factors of the primaries are fp = 81.2 (±0.2)% for EU Hya and fp = 82.4 (±0.3)% for AW Vul. Period analysis implies that there exists a downward parabola with a light-time orbit from the (O - C) curve. This kind of periodic oscillation may be attributed to the light-time orbit effect of a third companion. The long-term period decrease may be caused by mass and angular momentum loss. When the orbital period decreases, the fill-out factor of fp will increase. Our results indicate that the primaries will also eventually fill their Roche lobes. EU Hya and AW Vul may possibly evolve from semi-detached binaries into contact ones.

  11. 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...

  12. The Kepler Eclipsing System KIC 5621294 and its Substellar Companion

    CERN Document Server

    Lee, Jae Woo; Hinse, Tobias Cornelius

    2014-01-01

    We present the physical properties of KIC 5621294 showing light and timing variations from the ${\\it Kepler}$ photometry. Its light curve displays partial eclipses and 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$^\\circ$.8, and $\\Delta$($T_{1}$--$T_{2}$)=4,235 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 \\& van Woerden. These are mainly caused by surface inhomogeneities due to spot activity detected in our light-curve synthesis. The 1,253 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 a periodic variation overlaid on a downward parabola. The sinusoidal variation ...

  13. A comprehensive photometric study of the eclipsing binary EP Aurigae

    Science.gov (United States)

    Li, H.-L.; Wei, J.-Y.; Yang, Y.-G.; Li, K.; Zhang, X.-B.

    2015-02-01

    We present new observations for the eclipsing binary EP Aurigae, which were performed by using three small telescopes in China from 2003 December to 2014 January. With the updated 2003 version of the Wilson-Devinney code, the photometric elements were deduced from three sets of light curves. Based on all available eclipsing times, the orbital period changes were investigated. It is discovered that the (O-C) curve may show an existence of light-time effect due to an unseen third body, which was weakly identified by the photometric solution. The modulated period and amplitude of the cyclic variation are P3=71.2(±8.0) yr and A=0.0101(±0.0008) day, respectively. In the co-planar orbit with the binary system, the mass of the third body is M3=0.18(±0.02) M⊙. The photometric results imply that EP Aur is an Algol-type binary with a mass ratio of q=0.831(±0.004). Its primary component almost fills its Roche lobe. Therefore, EP Aur may consist of a normal main-sequence star and a cool Roche-lobe filling subgiant, which may be undergoing rapid mass transfer.

  14. 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...

  15. 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.

  16. 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.

  17. KIC 8262223: A Post-Mass Transfer Eclipsing Binary Consisting of a Delta Scuti Pulsator and a Helium White Dwarf Precursor

    CERN Document Server

    Guo, Zhao; Matson, Rachel A; Hernández, Antonio García; Han, Zhanwen; Chen, Xuefei

    2016-01-01

    KIC~8262223 is an eclipsing binary with a short orbital period ($P=1.61$ d). The {\\it Kepler} light curves are of Algol-type and display deep and partial eclipses, ellipsoidal variations, and pulsations of Delta Scuti type. We analyzed the {\\it Kepler} photometric data, complemented by phase-resolved spectra from the R-C Spectrograph on the 4-meter Mayall telescope at Kitt Peak National Observatory and determined the fundamental parameters of this system. The low mass and oversized secondary ($M_2=0.20M_{\\odot}$, $R_2=1.31R_{\\odot}$) is the remnant of the donor star that transferred most of its mass to the gainer, and now the primary star. The current primary star is thus not a normal $\\delta$ Scuti star but the result of mass accretion from a lower mass progenitor. We discuss the possible evolutionary history and demonstrate with the MESA evolution code that the system can be understood as the result of non-conservative binary evolution similar to that for the formation of EL CVn type binaries. The pulsation...

  18. A Spectroscopic Study of Kepler Asteroseismic Targets

    CERN Document Server

    Molenda-Zakowicz, J; Latham, D W; Jerzykiewicz, M

    2009-01-01

    Reported are spectroscopic observations of 15 candidates for Kepler primary asteroseismic targets and 14 other stars in the Kepler field, carried out at three observatories (see the footnote). For all these stars, the radial velocities, effective temperature, surface gravity, metallicity, and the projected rotational velocity are derived from two separate sets of data by means of two independent methods. In addition, MK type is estimated from one of these sets of data. Three stars, HIP 94335, HIP 94734, and HIP 94743, are found to have variable radial-velocity. For HIP 94335 = FL Lyr, a well-known Algol-type eclipsing variable and a double-lined spectroscopic binary, the orbital elements computed from our data agree closely with those of Popper et al. For HIP 94734 and HIP 94743 = V2077 Cyg, which we discover to be single-lined systems, orbital elements are derived. In addition, from our value of the orbital period and the Hipparcos epoch photometry, HIP 94743 is demonstrated to be a detached eclipsing binary...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. Piezometria-80 numerical model of aquiferous layer

    Energy Technology Data Exchange (ETDEWEB)

    Rogoz, M.; Solik-Heliasz, E.

    1988-01-01

    Discusses the PIEZOMETRIA-80 subsystem for mathematical modeling (by means of the finite difference method) of aquifers consisting of a single water-bearing layer under conditions of unstable filtration. The subsystem consists of four programs+: PREMOD-80 for reading data on perforated tapes and cards, interpolation and extrapolation of data and generating tables that correspond with the assumed discretization of a modeled area; PRZEWODNOSC-80 for solving inverse problem of filtration (e.g. determining rock permeability to water); PIEZO-80 for calculating coordinates of a water level at given time intervals; WYNIK-80 for graphical presentation of calculation results on maps and diagrams. The PIEZOMETRIA subsystem is developed in two language versions: Algol 1204 version A and Fortran 1900 version F for the Odra 1204 and Odra 1325 computers. Use of calculation methods and algorithms for the following purposes is discussed: development of schemes of hydrogeologic conditions, discretization of space and time, assignment of boundary conditions, determining parameters of aquifers. 3 refs.

  4. UX Ori Variables in the Cluster IC 348

    Science.gov (United States)

    Barsunova, O. Yu.; Grinin, V. P.; Sergeev, S. G.; Semenov, A. O.; Shugarov, S. Yu.

    2015-06-01

    Results are presented from many years of photometric (VRCIC) observations of three variable T Tauri type stars in the cluster IC 348: V712 Per, V719 Per, and V909 Per. All three stars have photometric activity characteristic of UX Ori stars. The activity of V719 Per has increased significantly over the last 10 years: the amplitude of its Algol-like minima has increased by roughly a factor of 4 and has reached three stellar magnitudes in the I band. Periodograms of the light curves do not confirm the periods found previously by other authors on the basis of shorter series of observations. The slope of the color tracks on "color-magnitude" diagrams is used to determine the reddening law for these stars owing to selective absorption by circumstellar dust. Modelling of these parameters by the Mie theory shows that the maximum size amax of the dust particles in the protoplanetary disks of these stars is 1.5-2 times greater than in the interstellar medium. In V712 Per and V909 Per, the bulk of the mass of the dust particles is concentrated near amax, while in V719 Per the average mass of the dust particles is determined by the minimum size of the particles. It should be emphasized that these conclusions rely on an analysis of the optical variability of these stars.

  5. 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

  6. Invited Talk: Photometry of Bright Variable Stars with the BRITE Constellation Nano-Satellites: Opportunities for Amateur Astronomers

    Science.gov (United States)

    Guinan, E. F.

    2014-06-01

    (Abstract only) The BRIght Target Explorer (BRITE) is a joint Austrian-Canadian-Polish Astronomy mission to carry out high precision photometry of bright (mv computers, and so on. The first two (of up to six) satellites were successfully launched during February 2013. After post-launch commissioning, science operations commenced during October 2013. The primary goals are to carry out continuous multi-color (currently blue and red filters) high-precision millimag (mmag) photometry in particular locations in the sky. Typically these pointings will last for two to four months and secure simultaneous blue/red photometry of bright variable stars within the field. The first science pointing is centered on the Orion region. Since most bright stars are intrinsically luminous, hot O/B stars, giants, and supergiants will be the most common targets. However, some bright eclipsing binaries (such as Algol, b Lyr, e Aur) and a few chromospherically-active RS CVn stars (such as Capella) may be eventually be monitored. The BRITE-Constellation program of high precision, two color photometry of bright stars offers a great opportunity to study a wide range of stellar astrophysical problems. Bright stars offer convenient laboratories to study many current and important problems in stellar astrophysics. These include probing stellar interiors and pulsation in pulsating stars, tests of stellar evolution and structure for Cepheids and other luminous stars. To scientifically enhance the BRITE science returns, the BRITE investigators are very interested in securing contemporaneous ground-based spectroscopy and standardized photometry of target stars. The BRITE Ground Based Observations Team is coordinating ground-based observing efforts for BRITE targets. The team helps coordinate collaborations with amateur and professional astronomer. The ground-based coordinators are: Thomas Eversberg (thomas.eversberg@dlr.de) and, for spectroscopy, Contanze Zwintz (konstanze@ster.kuleuven.be). Detailed

  7. The Near-contact Binary RZ Draconis with Two Possible Light-time Orbits

    Science.gov (United States)

    Yang, Y.-G.; Li, H.-L.; Dai, H.-F.; Zhang, L.-Y.

    2010-12-01

    We present new multicolor photometry for RZ Draconis, observed in 2009 at the Xinglong Station of the National Astronomical Observatories of China. By using the updated version of the Wilson-Devinney Code, the photometric-spectroscopic elements were deduced from new photometric observations and published radial velocity data. The mass ratio and orbital inclination are q = 0.375(±0.002) and i = 84fdg60(±0fdg13), respectively. The fill-out factor of the primary is f = 98.3%, implying that RZ Dra is an Algol-like near-contact binary. Based on 683 light minimum times from 1907 to 2009, the orbital period change was investigated in detail. From the O - C curve, it is discovered that two quasi-sinusoidal variations may exist (i.e., P 3 = 75.62(±2.20) yr and P 4 = 27.59(±0.10) yr), which likely result from light-time effects via the presence of two additional bodies. In a coplanar orbit with the binary system, the third and fourth bodies may be low-mass drafts (i.e., M 3 = 0.175 M sun and M 4 = 0.074 M sun). If this is true, RZ Dra may be a quadruple star. The additional body could extract angular momentum from the binary system, which may cause the orbit to shrink. With the orbit shrinking, the primary may fill its Roche lobe and RZ Dra evolves into a contact configuration.

  8. The Kepler Eclipsing System KIC 5621294 and Its Substellar Companion

    Science.gov (United States)

    Lee, Jae Woo; Hong, Kyeongsoo; Hinse, Tobias Cornelius

    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(T1-T2) = 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 & 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}3}sin {{i}3} = 46.9 MJup, 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.

  9. 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.

  10. 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.

  11. 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.

  12. Light curve analysis of GSC 2750-0054 and GSC 03208-02644

    Science.gov (United States)

    Elkhateeb, M. M.; Nouh, M. I.

    2016-11-01

    We present the first photometric analysis for the newly discovered eclipsing binary systems of Algole-type GSC 2750-0054 and GSC 03208-02644. Our analysis was carried out by means of the most recent version of Wilson Devinney (WD) code, which applies the model atmosphere by (Kurucz, R., 1993. In: Milon, E. (Ed.), Light Curve Modeling of Eclipsing Binary Stars. Springer-Verlag, New York, p. 93) with a prescription in passband for the radiative treatment. The accepted light curve solutions reveal absolute physical parameters and the spectral classifications for the components are adopted. We derived the spectral types of the system GSC 2750-0054 as K3 and K7. The physical parameters of the system are M1 = 0.72 ± 0.03 M⊙, M2 = 0.47 ± 0.02 M⊙, R1 = 0.81 ± 0.03 R⊙, R2 = 0.62 ± 0.03 R⊙, L1 = 0.27 ± 0.01 L⊙ and L2 = 0.1 ± 0.004 L⊙. For the system, GSC 03208 02644 the spectral types of the components are A5 and A8. The physical parameters are M1 = 1.86 ± 0.076 M⊙, M2 = 1.21 ± 0.049 M⊙, R1 = 1.84 ± 0.075 R⊙, R2 = 1.75 ± 0.072 R⊙, L1 = 13.58 ± 0.55 L⊙ and L2 = 9.94 ± 0.41 L⊙. Comparison with the evolutionary models as well as the empirical databases is presented.

  13. 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.

  14. From Top to Bottom - the Multiwavelength Campaign of V824 Ara (HD 155555)

    Science.gov (United States)

    Dempsey, Robert; Neff, James; Strassmeier, Klaus; Linsky, Jeffrey; Lim, Jeremy; Donati, J.-F.; Walter, Fred; Marang, Fred; Budding, Edwin; Jordan, Ian; Walker, Stan; Downing, David G.; Inwood, Doug; Petterson, Orlon; Petterson, Orlon

    1997-01-01

    A great deal of progress has been made in recent years in decomposing the 2-D structure in the atmospheres of late-type stars. Doppler images of many photospheres single stars, T Tauri stars, Algols, RS CV(sub n) binaries to name a few - are regularly published (Strassmeier 1996; Richards and Albright 1996; Rice and Strassmeier 1996; Kuerster et al. 1994). Ultraviolet spectral images of chromospheres appear in the literature (e.g., Walter et al. 1987; Neff et al. 1989) but are less common owing to the difficult nature of obtaining complete phase coverage. Zeeman doppler images of magnetic fields are now feasible (e.g., Donati et al. 1992). Performing Doppler imaging of the same targets over many seasons has also been accomplished (e.g, Vogt et al. 1997). Even when a true image reconstruction is not possible due to poor spectral resolution, we can still infer a great deal about spatial structure if enough phases are observed. However, it is increasingly apparent that to make sense of recent results, many different spectral features spanning a range of formation temperature and density must be observed simultaneously for a coherent picture to emerge. Here we report on one such campaign. In 1996, we observed the southern hemisphere RS CV(sub n) binary V824 Ara (P=1(sup d).68, G5IV+K0V-IV-IV) over one complete stellar rotation with the Hubble Space Telescope and EUVE. In conjunction, radio and optical photometry and spectroscopy were obtained from the ground. Unique to this campaign is the complete phase coverage of a number of activity proxy indicators that cover source temperatures ranging from the photosphere to the corona.

  15. 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

  16. 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

  17. Obituary: James C. Kemp, 1927-1988

    Science.gov (United States)

    Milone, E. F.

    2009-01-01

    James C. Kemp was born in Detroit, Michigan on 9 February 1927, and died in Eugene, Oregon, on 29 March 1988. He went to high school in Mexico City and did undergraduate studies at the University of Michigan and University of California at Berkeley. Kemp was an active observational astronomer, having migrated from earlier interests in Slavic languages, in which he majored, electrical engineering, and physics. He obtained a PhD in electrical engineering at Berkeley in 1960 and did post-doctoral work there with Erwin Hahn on spin resonance. He went to the University of Oregon in 1961 and conducted research in magneto-optics, developing, in the process, a piezo-optical birefringence modulator to measure circular polarization. The modulator is described by Tinbergen (1996). Kemp explored new areas as he measured magnetic fields in the sunspots with polarized infrared light, and developed polarimeters and photometers to study the behavior of such astronomical sources as white dwarfs, the relativistic jets of binary SS 433, the x-ray binary Cyg X-1, and the bright eclipsing binaries Algol and e Aurigae on the 61- and, later, 81-cm telescope at the Pine Mountain Observatory, of which Kemp was director until his death from cancer. His measurement of circularly polarization in the continuum light of the white dwarf GJ 742 (Grw +70∘ 8247, Kemp et al. 1970b) was an important discovery, and through his study of Algol (Kemp et al. 1983; Wilson & Liou 1993), he appears to have been the first to discover the limb polarization in eclipsing binaries predicted by Chandrasekhar (1946ab). Although it has taken twenty years for the BAAS to publish his obituary notice, it is somewhat appropriate that his former student, Gary Henson, who provided much of the background for this article, is involved with a polarimetry team to observe and analyze data from e Aurigae, as it approaches ingress of the next primary minimum beginning summer, 2009. The author acknowledges with gratitude the

  18. 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

  19. Large X-ray flares on stars detected with MAXI/GSC: A universal correlation between the duration of a flare and its X-ray luminosity

    Science.gov (United States)

    Tsuboi, Yohko; Yamazaki, Kyohei; 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

    2016-10-01

    Twenty-three giant flares from thirteen active stars (eight RS CVn systems, one Algol system, three dMe stars, and one young stellar object) 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 these MAXI/GSC flares are found to be at the upper ends for stellar flares with the luminosity of 1031-34 erg s-1 in the 2-20 keV band, the emission measure of 1054-57 cm-3, the e-folding time of 1 hr to 1.5 d, and the total radiative energy released during the flare of 1034-39 erg. Notably, the peak X-ray luminosity of 5^{+4}_{-2} × 10^{33}erg 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). Among the stellar sources within 100 pc distance, the MAXI/GSC sources have larger rotation velocities than the other sources. This suggests that the rapid rotation velocity may play a key role in generating large flares. Combining the X-ray flare data of nearby stars and the sun, taken from literature and our own data, we discovered a universal correlation of τ ∝ L_X^{0.2} for the flare duration τ and the intrinsic X-ray luminosity LX in the 0.1-100 keV band, which holds for 5 and 12 orders of magnitude in τ and LX, respectively. The MAXI/GSC sample is located at the highest ends of the correlation.

  20. 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

  1. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sesar, Branimir; Ivezic, Zeljko; Lupton, Robert H.; Juric, Mario; Gunn, James E.; Knapp, Gillian R.; Lee, Nathan De; Smith, J.Allyn; Miknaitis, Gajus; Lin, Huan; Tucker,

    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 < {delta}{sub J2000} < +1.27, {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} 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 ux-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 Telescope and

  3. 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.

  4. 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)