Volume 526, February 2011
|Number of page(s)||15|
|Section||Stellar structure and evolution|
|Published online||16 December 2010|
Orbital and physical parameters of eclipsing binaries from the All-Sky Automated Survey catalogue
II. Two spotted M < 1 M⊙ systems at different evolutionary stages⋆
Nicolaus Copernicus Astronomical Center, Department of
ul. Rabiańska 8,
e-mail: email@example.com; firstname.lastname@example.org
2 Astronomical Observatory, Adam Mickiewicz University, ul. Słoneczna 36, 60-286 Poznań, Poland
Received: 22 September 2009
Accepted: 19 September 2010
Methods. With the HIgh Resolution Echelle Spectrometer (HIRES) on the Keck-I telescope, we obtained spectra of both objects covering large fractions of orbits of the systems. We also obtained V and I band photometry with the 1.0-m Elizabeth telescope of the South African Astronomical Observatory (SAAO). The orbital and physical parameters of the systems were derived with the PHOEBE and JKTEBOP codes. We investigated the evolutionary status of both binaries with several sets of widely-used isochrones.
Results. Our modelling indicates that (1) ASAS J045304-0700.4 is an old, metal-poor, active systemwith component masses of M1 = 0.8338 ± 0.0036 M⊙, M2 = 0.8280 ± 0.0040 M⊙ and radii of R1 = 0.848 ± 0.005 R⊙ and R2 = 0.833 ± 0.005 R⊙, which places it at the end of the Main Sequence evolution – a stage rarely observed for this type of stars. (2) ASAS J082552-1622.8 is a metal-rich, active binary with component masses of M1 = 0.7029 ± 0.0045 M⊙, M2 = 0.6872 ± 0.0049 M⊙ and radii of and . Both systems show significant out-of-eclipse variations, probably owing to large, cold spots.We also investigated the influence of a third light in the second system.
Key words: binaries: eclipsing / binaries: spectroscopic / stars: fundamental parameters / stars: individual: ASAS J045304-0700.4 / stars: late-type / stars: individual: ASAS J082552-1622.8
Light curves are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/526/A29
© ESO, 2010
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