Volume 526, February 2011
|Number of page(s)||6|
|Section||Stellar structure and evolution|
|Published online||13 January 2011|
Near-infrared SOAR photometric observations of post common envelope binaries⋆
Departamento de FísicaUniversidade Federal de Santa Catarina,
Accepted: 19 November 2010
Context. From a number of known post common envelopes binaries (PCEB) only a handful have yet been observed at near-infrared (NIR) wavelengths, and even fewer have modeled NIR light curves. At shorter wavelengths one has access to the cooler and larger components of these systems and has a chance to detect emission from its faint and heavily irradiated atmospheres.
Aims. By modeling NIR light curves of PCEBs, we intend to constrain their system parameters and study the properties of the system components.
Methods. Here we present simultaneous NIR JHKs light curves of two PCEBs obtained with the 4 m SOAR telescope.
Results.KV Vel and TW Crv are long-period (Porb = 8.6 h and 7.9 h, respectively) PCEBs with strong irradiation effects. The results of light-curve fitting provided solutions with inclination i = (47 ± 5)°, mass ratio q = 0.3 ± 0.1, and radius of the secondary (where a is the orbital separation) for KV Vel, and i = (42 ± 9)°, q = 0.28 ± 0.04, and R2/a = 0.22 ± 0.01 for TW Crv, respectively. For KV Vel, we obtain an average value for the albedo of the secondary star of α = 0.43, consistent in the J, H and Ks band. For TW Crv, on the other hand, we obtain values of αJ = (0.4 ± 0.1) for the J and αH = (0.3 ± 0.1) for H-band.
Key words: binaries: close / stars: fundamental parameters / ephemerides / binaries: spectroscopic / subdwarfs
The near-infrared photometric data can be retrieved at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A150
© ESO, 2011
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