bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconstruction of an Accretion Disk Image in AU Mon from CoRoT Photometry
Authors: Mimica P. , Pavlovski K. 
Published: April 2012

AbstractThe long-period binary system AU Mon was photometrically observed on-board the CoRoT satellite in a continuous run of almost 60 days long which has covered almost 5 complete cycles. Unprecedented sub milimag precision of CoRoT photometry reveals all complexity of its light variations in this, still active mass-transfer binary system. We present images of an accretion disk reconstructed by eclipse mapping, and an optimization of intensity distribution along disk surface. Time resolution and accurate CoRoT photometric measurements allow precise location of spatial distribution of ‘hot’ spots on the disk, and tracing temporal changes in their activity. Clumpy disk structure is similar to those we detected early for another W Serpentis binary W Cru (Pavlovski, Burki & Mimica, 2006, A&A, 454, 855).
Multiwavelength Modeling the SED of Strongly Interacting Binaries
Authors: Skopal Augustin 
Published: April 2012

AbstractThe spectrum of strongly interacting binaries, as for example, high and low mass X-ray binaries, symbiotic (X-ray) binaries and/or classical and recurrent novae, consists of more components of radiation contributing from hard X-rays to radio wavelengths. To understand the basic physical processes responsible for the observed spectrum we have to disentangle the composite spectrum into its individual components, i.e. to determine their physical parameters. In this short contribution I demonstrate the method of modeling the multiwavelength SED on the example of the extragalactic super-soft X-ray source RX J0059.1-7505 (LIN 358).
Planets in Binary Systems
Authors: Pilello Antonio 
Published: April 2012

AbstractIn close eclipsing binary systems, measurements of the eclipse timing variations (ETV), obtained by means of accurate light curves, may be used to find circumbinary additional objects. The presence of these objects causes the motion of the eclipsing binary with respect to the centre of mass of the entire system and it results in advances or delays in the times of eclipses due to the light time effect. The most important issue of this project is to inspect the potential of detecting low mass substellar companions to close eclipsing binaries through the timing method. For this purpose, we use the public data from Kepler and CoRoT spacecrafts, collecting the light curves for a selected sample and analyzing the observed minus calculated (O-C) times of the eclipses in the search for ETVs and characterizing them. A large amplitude of the O-C ETVs can be explained in some cases by the presence of a third body in the system.
Probing Bow Shocks Around Exoplanets During Transits
Authors: Vidotto A. A. , Jardine M. , Helling C. 
Published: April 2012

AbstractHere, we summarise the conditions that might lead to the formation of a bow shock surrounding a planet's magnetosphere. Such shocks are formed as a result of the interaction of a planet with its host star wind. In the case of close-in planets, the shock develops ahead of the planetary orbit. If this shocked material is able to absorb stellar radiation, the shock signature can be revealed in (asymmetric) transit light curves. We propose that this is the case of the gas giant planet WASP-12b, whose near-UV transit observations have detected the presence of an extended material ahead of the planetary orbit. We show that shock detection through transit observations can be a useful tool to constrain planetary magnetic fields.
The Orbital Period Distribution of Cataclysmic Variables Found by the SDSS
Authors: Southworth John , Gänsicke Boris T. , Breedt Elmé 
Published: April 2012

AbstractThe orbital period is one of the most accessible observables of a cataclysmic variable. It has been a concern for many years that the orbital period distribution of the known systems does not match that predicted by evolutionary theory. The sample of objects discovered by the Sloan Digital Sky Survey has changed this: it shows the long-expected predominance of short-period objects termed the ‘period spike’. The minimum period remains in conflict with theory, suggesting that the angular momentum loss mechanisms are stronger than predicted.
Space-Based Photometry of Eclipsing Binaries
Authors: Southworth John 
Published: April 2012

AbstractI briefly review the history and prospects for the study of eclipsing binary star systems from space-based observatories. The benefits of shifting to space satellites lie in the high precision and cadence achievable, as well as the ability to access wavelength regions which are unattainable from the ground. Whilst small amounts of data on eclipsing binaries were obtained by the Voyager, IUE, OAO-II, Hipparcos and MOST, the more recent CoRoT and Kepler missions were the first to provide extensive data on large numbers of systems. The future holds the prospect of the PLATO satellite, which will go bigger, better and brighter.
Homogeneous Studies of Transiting Planets
Authors: Southworth John 
Published: April 2012

AbstractThe derived physical properties of the known transiting extrasolar planetary systems come from a variety of sources, and are calculated using a range of different methods so are not always directly comparable. I present a catalogue of the physical properties of 58 transiting extrasolar planet and brown dwarf systems which have been measured using homogeneous methods, resulting in quantities which are internally consistent and well-suited to detailed statistical study. The main results for each object, plus a critical compilation of literature values for all known systems, have been placed in an online catalogue. TEPCat can be found at http://www.astro.keele.ac.uk/~jkt/tepcat/
Light Curves of Planetary Transits: How About Ellipticity?
Authors: von Essen Carolina , Huber Klaus F. , Schmitt Jürgen H. M. M. 
Published: April 2012

AbstractThe observation of transit light curves has become a key technique in the study of exoplanets, since modeling the resulting transit photometry yields a wealth of information on the planetary systems. Considering that the limited accuracy of ground-based photometry does directly translate into uncertainties in the derived model parameters, simplified spherical planet models were appropriate in the past. With the advent of space-based instrumentation capable of providing photometry of unprecedented accuracy, however, a need for more realistic models has arisen.
New Photometric Observations of the Transiting Extrasolar Planet TrES-3b
Authors: Vaňko M. , Jakubík M. , Krejčová T. , Maciejewski G. , Budaj J. , Pribulla T. , Ohlert J. , Raetz S. , Krushevska V. , Dubovsky P. 
Published: April 2012

AbstractWe present new transit observations of the transiting exoplanet TrES-3b obtained in the range 2009 – 2011 at several observatories. The orbital parameters of the system were redetermined and the new linear ephemeris was calculated. We performed numerical simulations for studying the long-term stability of orbits.
Asymmetric Transit Curves as Indication of Orbital Obliquity: Clues from the Brown Dwarf Companion in KOI-13
Authors: Szabó G. M. , Szabó R. , Benkö J. M. , Lehmann H. , Mezö G. , Simon A. E. , Kövári Z. , Hodosán G. , Regály Z. , Kiss L. L. 
Published: April 2012

AbstractExoplanets orbiting rapidly rotating stars may have unusual light curve shapes. These objects transit across an oblate disk with non-isotropic surface brightness, caused by the gravitational darkening. If such asymmetries are measured, one can infer the orbital obliquity of the exoplanet and the gravity darkened star, even without the analysis of the Rossiter-McLaughlin effect or interferometry. Here we introduce KOI-13 as the first example of a transiting system with a gravity darkened star.
New Binary and Exoplanet Candidates from STEREO Light Curves
Authors: Whittaker Gemma , Sangaralingam Vino , Stevens Ian 
Published: April 2012

AbstractThe Heliospheric Imagers (HI) onboard the STEREO satellites are observing an abundance of background stars as they follow their respective Sun-centered orbits. These are wide-angled CCD cameras with a 20°×20° field of view, directed ~14° from the solar disk. These imagers monitor 20% of the sky over one year, providing light curves for over 500,000 stars down to 12th magnitude and brighter than 7th. We are currently analysing the photometric data from the HI-1 cameras, obtained since March 2007. Following a standard data reduction of the raw photometric images, the resultant light curves underwent a sequence of detrending procedures to minimize systematics in the data, which can contribute to red noise. A transit search was performed using the BLS algorithm, which is sensitive to the box-like shape associated with planetary transits. The resulting candidates were subjected to a number of false-alarm tests to determine the most promising candidates and these were investigated further, visually and using available catalogue data. Possible new exoplanet and binary candidates will now be submitted for follow-up photometric and spectroscopic observations to confirm their nature.
Tomography of Interacting Binary Systems: Algols to Gamma-Ray Binaries
Authors: Richards Mercedes T. 
Published: April 2012

AbstractThree-dimensional Doppler tomography of interacting binaries has now provided some interesting perspectives of the gas flows beyond the central plane corresponding to the orbital plane. These images suggest that the magnetic field of the mass losing star influences the gas flows in some cases. Earlier 2D tomograms displayed evidence of gas flows associated with the gas stream, accretion disks, accretion annuli, and hot spots as well as evidence of magnetic flows associated with the mass loser. These indirect images have revealed the active environments that exist in the slow-mass-transfer Algols, cataclysmic variables, polars, x-ray binaries, and gamma ray binaries.
Lucky Imaging Survey for Binary Exoplanet Hosts
Authors: Bergfors Carolina , Brandner Wolfgang , Daemgen Sebastian , Henning Thomas 
Published: April 2012

AbstractBinary or multiple stars are common in our neighbourhood, and many of the exoplanets we know of belong to a star in such a system. The influence of a second star on planet formation can be probed by comparing properties of planets in binary/multiple-star systems with those of single-star planets. We present some of the results from our Lucky Imaging survey for binary companions to hosts of transiting exoplanets.
LTE Model Atmospheres: MARCS, ATLAS and CO5BOLD
Authors: Bonifacio P. , Caffau E. , Ludwig H.-G. , Steffen M. 
Published: April 2012

AbstractIn this talk, we review the basic assumptions and physics covered by classical 1D LTE model atmospheres. We will focus on ATLAS and MARCS models of F-G-K stars and describe what resources are available through the web, both in terms of codes and model-atmosphere grids. We describe the advances made in hydrodynamical simulations of convective stellar atmospheres with the CO5BOLD code and what grids and resources are available, with a prospect of what will be available in the near future.
Modeling of Circumstellar Dust by the DUSTY Code
Authors: Jurkić Tomislav , Kotnik-Karuza Dubravka 
Published: April 2012

AbstractWe present a circumstellar dust model around the symbiotic Mira RR Tel obtained by modeling the near-infrared JHKL magnitudes and ISO spectra. In order to follow the evolution of infrared colours in time, the published JHKL magnitudes were corrected by removing the Mira pulsations. The RR Tel light curves show three obscuration events in the near-IR. Using the simultaneously available JHKL magnitudes and ISO spectra in three different epochs, we obtained SEDs in the near- and mid-IR spectral region (1-20 μm) in epochs with and without obscuration.The DUSTY numerical code was used to solve the radiative transfer and to determine the circumstellar dust properties of the inner dust regions around the Mira, assuming a spherical dust temperature distribution in its close neighbourhood. The physical properties of the dust, mass loss and optical depth during intervals with and without obscuration have been obtained. Both JHKL and ISO observations during the obscuration period can be reproduced with a spherical dust envelope, while ISO spectra outside obscuration show a different behaviour. The dynamical behaviour of the circumstellar dust was obtained by modeling the JHKL magnitudes observed during the span of more than 30 years.The DUSTY code was also successfully applied in the modeling of circumstellar dust envelopes of young stellar objects, such as Herbig Ae/Be stars.
Fitting of Silicon lines in UV and Balmer Hδ Line in Optical Spectra of B supergiant HD 198478
Authors: Jurkić Tomislav , Deković Mariza Sarta , Kotnik-Karuza Dubravka 
Published: April 2012

AbstractAtmospheric parameters of the Galactic early B-supergiant HD 198478 (55 Cyg) were determined from the UV silicon lines and optical Balmer Hδ 4101 Å line. TLUSTY synthetic spectra were broadened using the ROTIN numerical code in order to determine effective temperature, surface gravity, rotational and macroturbulent velocity.
New Galactic Candidate Luminous Blue Variables and Wolf-Rayet Stars
Authors: Stringfellow Guy S. , Gvaramadze Vasilii V. , Beletsky Yuri , Kniazev Alexei Y. 
Published: April 2012

AbstractWe have undertaken a near-infrared spectral survey of stars associated with compact mid-IR shells recently revealed by the MIPSGAL (24 μm) and GLIMPSE (8 μm) Spitzer surveys, whose morphologies are typical of circumstellar shells produced by massive evolved stars. Through spectral similarity with known Luminous Blue Variable (LBV) and Wolf-Rayet (WR) stars, a large population of candidate LBVs (cLBVs) and a smaller number of new WR stars are being discovered. This significantly increases the Galactic cLBV population and confirms that nebulae are inherent to most (if not all) objects of this class.
RaveSpan - Radial Velocity and Spectrum Analyzer
Authors: Pilecki Bogumil , Konorski Piotr , Gorski Marek 
Published: April 2012

AbstractThe RV analysis tool integrates widely used methods of radial velocity determination (CCF, TODCOR, BF) in an easy to use graphical environment. No advanced knowledge of these methods is required to use it. The obtained velocities may be immediately analyzed with the same tool as it comprises flexible fitting of orbital parameters, which includes the third body influence and pulsational velocities of the components. These features together help to establish the most accurate combination of templates, spectrum range, and method. Scripting functionality is to be implemented in the future.
Infinity – A New Program for Modeling Binary Systems
Authors: Attila Cséki , Latković Olivera 
Published: April 2012

AbstractInfinity is a new program for modeling binary systems. The model is based on Roche geometry with asynchronous rotation, including an assortment of effects like gravity and limb darkening, mutual irradiation, bright and dark spots and so on. However, Infinity brings innovations in the modeling of accretion disks, and introduces the modeling of radial and non-radial oscillations on one or both components of the system.At this stage of development, Infinity can produce light curves, spectra and radial velocity curves; solving the inverse problem is still a work in progress. In terms of programming, Infinity is being developed in the object-oriented language C#, and great care is taken to produce readable, easily extensible and verifiable code. Infinity is fully optimized to take advantage of modern multi-core CPUs, and the code is thoroughly covered with unit-tests. We expect to make a public release during 2012.
Period Changes of the Algol System SZ Herculis
Authors: Lee J. W. , Lee C.-U. , Kim S.-L. , Kim H.-I. , Park J.-H. , Hinse T. C. 
Published: April 2012

AbstractNew 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.
Methods of the Long-term Radial-Velocity Variation Removal and their Application to Detect Duplicity of Several Be Stars
Authors: Nemravová J. , Harmanec P. , Koubský P. , Miroshnichenko A. 
Published: April 2012

AbstractThere are several types of binary stars which show non-periodical radial velocity variations with the amplitude larger than those connected with the orbital motion. The non-periodical changes have to be removed in order to study the orbital ones. We propose three removal techniques, two of which are based on the trend modeling with continuous functions and the third one that takes the orbital motion into account.
The Effects of Eccentric Accretion Structures on the Light Curves of Interacting Algol-type Binary Stars
Authors: Reed Phillip A. 
Published: April 2012

AbstractThe light curves of many Algol-type binary stars are complicated with strange variations. Secular variations are due to the transient nature of the accretion structure, while the phase-dependent features, such as outside-of-eclipse dips, are likely geometrical effects of the accretion structure eclipsing the primary star. Presented here is a model of the ultraviolet light curve of R Arae that explains these variations through the combination of an eccentric accretion structure and the system's orbital inclination.The orbital period of R Ara is 4.4 days, which is too long to allow for direct impact of the mass transfer stream onto the primary star, but not long enough for a stable accretion disk to form. Such intermediate-period Algols are good candidates in which to find transient and eccentric accretion structures. Other examples of interacting Algols that exhibit outside-of-eclipse dips in their light curves include RV Oph (Porb.=3.7 days) and Y Psc (Porb.=3.9 days).In order to more accurately model eccentric accretion structures with synthetic light curves, especially at visible (and longer) wavelengths, more work must be done to account for emission by the parts of the accretion structure that are not in the line of sight to the primary star. The model presented here accounts only for the eclipsing regions of the accretion structure.
Spectroscopic Binaries Among λ Bootis-type Stars
Authors: Paunzen Ernst , Fraga Luciano , Heiter Ulrike , Iliev Ilian Kh. , Kamp Inga , Pintado Olga 
Published: April 2012

AbstractThe small group of λ Bootis stars comprises late B to early F-type stars, with moderate to extreme (up to a factor 100) surface under-abundances of most Fe-peak elements and solar abundances of lighter elements (C, N, O, and S). The main mechanisms responsible for this phenomenon are atmospheric diffusion, meridional mixing, and accretion of material from their surroundings. Especially spectroscopic binary (SB) systems with λ Bootis-type components are very important to investigate the evolutionary status and accretion process in more details. Because also δ Scuti type pulsation was found for several members, it gives the opportunity to use the tools of astroseismology for further investigations. We present the results of our long term efforts of detailed abundance analysis, orbital parameter estimation and photometric time series analysis for five well investigated SB systems.
Characterizing New Eclipsing Binaries Identified from STEREO Photometry
Authors: Markov Harry , Tsvetanov Zlatan , Iliev Ilian , Stateva Ivanka , Markova Nevena 
Published: April 2012

AbstractSince 2010, a program to explore new eclipsing binary systems identified from STEREO photometry has been in progress. Our first results are presented here: light curves and high resolution spectra taken with Coudé spectrograph (National Astronomical Observatory Rozhen) and ARC Échelle spectrometer (ARCES, Apache Point Observatory).
TODCOR – Two-Dimensional Correlation
Authors: Zucker Shay 
Published: April 2012

AbstractTODCOR is a TwO-Dimensional CORrelation technique to measure radial velocities of the two components of a spectroscopic binary. Assuming the spectra of the two components are known, the technique correlates an observed binary spectrum against a combination of the two spectra with different shifts. TODCOR measures simultaneously the radial velocities of the two stars by finding the maximum correlation. The main use of the technique has been to turn single-lined binaries into double-lined systems. This helps to explore the binary mass-ratio distribution, especially the low-mass regime, where the secondaries are usually very faint and therefore hard to detect. The technique has been generalized to study multi-order spectra, and also triple- and quadruple-lined systems. It has several applications in studying extrasolar planets and in the future may even help to dynamically measure stellar masses of binaries through relativistc effects.
Renormalization of KOREL-Decomposed SB2 Spectra
Authors: Lehmann Holger , Tkachenko Andrew 
Published: April 2012

AbstractWe introduce a new computer program that is able to determine the flux ratio between the components of SB2 stars from time series of composite spectra. The spectra of the components are decomposed using the KOREL program and compared to synthetic spectra computed on a grid of fundamental stellar parameters. In the result, we obtain the optimized stellar parameters together with the flux ratio. The program is tested and applied to the oscillating eclipsing binary KIC 10661783 observed by the Kepler satellite mission.
Planetary Dynamics in the α Centauri System: Lyapunov Spectra and Long-term Behaviour
Authors: Popova E. A. , Shevchenko I. I. 
Published: April 2012

AbstractThe stability of planetary motion in the binary system α Cen A–B is studied. Lyapunov spectra of the motion of the system with a single massive planet are computed on a fine grid of the initial data, and, by means of statistical analysis of the obtained data arrays, chaotic domains are identified in the “pericentric distance — eccentricity” initial data space for the planetary orbit. Association with the initial data domains for the orbits exhibiting close encounters with central stars and for the orbits exhibiting long-term escape is investigated.