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Eclipsing Binary (eclipsing + binary)

Distribution by Scientific Domains

Physics and Astronomy	100%

Selected Abstracts

Eclipsing binaries in open clusters , III.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2004
Persei, V621 Per in
ABSTRACT V621 Persei is a detached eclipsing binary in the open cluster , Persei, which is composed of an early B-type giant star and a main-sequence secondary component. From high-resolution spectroscopic observations and radial velocities from the literature, we determine the orbital period to be 25.5 d and the primary velocity semi-amplitude to be K= 64.5 ± 0.4 km s,1. No trace of the secondary star has been found in the spectrum. We solve the discovery light curves of this totally eclipsing binary and find that the surface gravity of the secondary star is log gB= 4.244 ± 0.054. We compare the absolute masses and radii of the two stars in the mass,radius diagram, for different possible values of the primary surface gravity, with the predictions of stellar models. We find that log gA, 3.55, in agreement with values found from fitting Balmer lines with synthetic profiles. The expected masses of the two stars are 12 and 6 M, and the expected radii are 10 and 3 R,. The primary component is near the blue loop stage in its evolution. [source]

Eclipsing binaries in the MOST satellite fields

ASTRONOMISCHE NACHRICHTEN, Issue 4 2010
T. Pribulla
Abstract Sixteen new eclipsing binaries have been discovered by the MOST satellite among guide stars used to point its telescope in various fields. Several previously known eclipsing binaries were also observed by MOST with unprecedented quality. Among the objects we discuss in more detail are short-period eclipsing binaries with eccentric orbits in young open clusters: V578 Mon in NGC 2244 and HD 47934 in NGC 2264. Long nearly-continuous photometric runs made it possible to discover three long-period eclipsing binaries with orbits seen almost edge-on: HD 45972 with P = 28.1 days and two systems (GSC 154 1247 and GSC 2141 526) with P > 25 days. The high precision of the satellite data led to discoveries of binaries with very shallow eclipses (e.g., HD 46180 with A = 0.016 mag, and HD 47934 with A = 0.025 mag). Ground-based spectroscopy to support the space-based photometry was used to refine the models of several of the systems (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Orbital and physical parameters of eclipsing binaries from the All-Sky Automated Survey catalogue , I. A sample of systems with components' masses between 1 and 2 M,

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2009
K. G. He, miniak
ABSTRACT We derive the absolute physical and orbital parameters for a sample of 18 detached eclipsing binaries from the All-Sky Automated Survey (ASAS) data base based on the available photometry and our own radial velocity (RV) measurements. The RVs are computed using spectra we collected with the 3.9-m Anglo-Australian Telescope (AAT) and its University College London Echelle Spectrograph (UCLES), and the 1.9-m Radcliffe telescope and its Grating Instrument for Radiation Analysis with a Fibre-Fed Echelle (GIRAFFE) at the South African Astronomical Observatory (SAAO). In order to obtain as precise RVs as possible, most of the systems were observed with an iodine cell available at the AAT/UCLES and/or analysed using the two-dimensional cross-correlation technique (TODCOR). The RVs were measured with TODCOR using synthetic template spectra as references. However, for two objects we used our own approach to the tomographic disentangling of the binary spectra to provide observed template spectra for the RV measurements and to improve the RV precision even more. For one of these binaries, AI Phe, we were able to the obtain an orbital solution with an RV rms of 62 and 24 m s,1 for the primary and secondary, respectively. For this system, the precision in M sin3i is 0.08 per cent. For the analysis, we used the photometry available in the ASAS data base. We combined the RV and light curves using phoebe and jktebop codes to obtain the absolute physical parameters of the systems. Having precise RVs, we were able to reach ,0.2 per cent precision (or better) in masses in several cases but in radii, due to the limited precision of the ASAS photometry, we were able to reach a precision of only 1 per cent in one case and 3,5 per cent in a few more cases. For the majority of our objects, the orbital and physical analysis is presented for the first time. [source]

Properties of analytic transit light-curve models

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008
András Pál
ABSTRACT In this paper, a set of analytic formulae is presented with which the partial derivatives of the flux obscuration function can be evaluated , for planetary transits and eclipsing binaries , under the assumption of quadratic limb darkening. The knowledge of these partial derivatives is crucial for many of the data modelling algorithms and estimates of the light-curve variations directly from the changes in the orbital elements. These derivatives can also be utilized to speed up some of the fitting methods. A gain of ,8 in computing time can be achieved in the implementation of the Levenberg,Marquardt algorithm, relative to using numerical derivatives. [source]

All-Sky Automated Survey eclipsing binaries with observed high period change rates

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2007
B. Pilecki
ABSTRACT We present 31 bright eclipsing contact and semidetached binaries that showed high period change rates (HPCRs) in a 5-yr interval in observations by the All-Sky Automated Survey. The time-scales of these changes range from only 50 up to 400 kyr. The orbital periods of 10 binaries are increasing and of 21 are decreasing, and even a larger excess is seen in contact binaries, where the numbers are 5 and 17, respectively. Period change has previously been noticed for only two of these binaries; our observations confirmed a secular period drift for SV Cen and period oscillations for VY Cet. The spectroscopic quadruple system V1084 Sco shows both period change and brightness modulation. According to our results, the incidence of asymmetry in the brightness at maximum light in the HPCR domain may be different from the incidence in the general population. All investigated binaries were selected from a sample of 1711 (1135 contact and 576 semidetached) that fulfilled all criteria of data quality. We also introduce a ,branch' test to check if luminosity changes on part of the binary's photosphere have led to a spurious or poorly characterized period change detection. [source]

Eclipsing binaries in the MOST satellite fields

Analysis of , Librae including Hipparcos astrometry

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006
V. Bak
ABSTRACT New spectroscopy of the classical Algol system , Lib, combined with high-quality optical and infrared photometry, provides the basis for a good understanding of the close binary system's main parameters. Detailed analysis of the photometry reveals the significant role of a third light source, pointing to the existence of a companion to the eclipsing system of mass ,1 M,. We review the methodology of applying high-accuracy positional information, available from the Hipparcos Intermediate Astrometric Data archive, to stars that may have such companions. Analysis of the astrometry of , Lib also points to a third star similar to the one already identified by Worek from radial-velocity data, although with slightly revised parameters. O,C data do not contradict this, but their general precision (while confirming the close pair's Algol status) fails to allow a decision on the third orbit parameters: Worek's or revised ones. Taking the photometry, spectroscopy and astrometry together, however, the existence of a third star of comparable mass to the Sun, as a relatively close companion to the eclipsing binary (,4 au), is confirmed. [source]

Eclipsing binaries in open clusters , III.

Discovery of the strongly eccentric, short-period binary nature of the B-type system HD 313926 by the MOST satellite,

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007
Slavek M. Rucinski
ABSTRACT The MOST photometric space mission discovered an eclipsing binary among its guide stars in 2006 June which combines a relatively large eccentricity e= 0.20 with an orbital period of only 2.27 d. HD 313926 appears to consist of two early-type stars of spectral type B3,B7. It has the largest eccentricity among known early-type binaries with periods less than 3.5 d. Despite the large components indicated by its spectral type and light curve model, and its short period, the orbit of HD 313926 has not yet circularized so it is probably very young, even compared with other young B stars. [source]

TYC 1031 01262 1: the first known Galactic eclipsing binary with a Type II Cepheid component

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007
S. V. Antipin
ABSTRACT We present the discovery and CCD observations of the first eclipsing binary with a Type II Cepheid component in our Galaxy. The pulsation and orbital periods are found to be 4.1523 and 51.38 d, respectively, i.e. this variable is the system with the shortest orbital period among known Cepheid binaries. Pulsations dominate the brightness variations. The eclipses are assumed to be partial. The EB-subtype eclipsing light curve leads us to believe that the binary components are non-spherical. [source]

Photometric analysis of the eclipsing binary 2MASS 19090585+4911585,

ASTRONOMISCHE NACHRICHTEN, Issue 5 2009
St. Raetz
Abstract We report on observations of the eclipsing binary 2MASS 19090585+4911585 with the 25 cm auxiliary telescope of the University Observatory Jena. We show that a nearby brighter star (2MASS 19090783+4912085) was previously misclassified as the eclipsing binary and find 2MASS 19090585+4911585 to be the true source of variation. We present photometric analysis of VRI light curves. The system is an overcontact binary of W UMa type with an orbital period of (0.288374 ± 0.000010) d (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]