A photometric and spectroscopic study of NSVS 14256825: the second sdOB+dM eclipsing binary
Abstract
We present an analysis of UBVRCICJH photometry and phase-resolved optical spectroscopy of NSVS 14256825, an HW Vir type binary. The members of this class consist of a hot subdwarf and a main-sequence low-mass star in a close orbit (Porb∼ 0.1 d). Using the primary-eclipse timings, we refine the ephemeris for the system, which has an orbital period of 0.110 37 d. From the spectroscopic data analysis, we derive the effective temperature, T1= 40 000 ± 500 K, the surface gravity, log g1= 5.50 ± 0.05, and the helium abundance, ?, for the hot component. Simultaneously modelling the photometric and spectroscopic data using the Wilson-Devinney code, we obtain the geometrical and physical parameters of NSVS 14256825. Using the fitted orbital inclination and mass ratio (i= 82°.5 ± 0°.3 and q=M2/M1= 0.260 ± 0.012, respectively), the components of the system have M1= 0.419 ± 0.070 M⊙, R1= 0.188 ± 0.010 R⊙, M2= 0.109 ± 0.023 M⊙ and R2= 0.162 ± 0.008 R⊙. From its spectral characteristics, the hot star is classified as a subdwarf OB (sdOB) star. Based on observations carried out at the Observatório do Pico dos Dias/Laboratório Nacional de Astrofísica (OPD/LNA) in Brazil.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2012
- DOI:
- 10.1111/j.1365-2966.2012.20891.x
- arXiv:
- arXiv:1203.1266
- Bibcode:
- 2012MNRAS.423..478A
- Keywords:
-
- binaries: eclipsing;
- stars: fundamental parameters;
- stars: individual: NSVS 14256825;
- stars: low-mass;
- subdwarfs;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 8 pages, 7 figures, accepted for publication in MNRAS