Bibcode
Parsons, S. G.; Gänsicke, B. T.; Marsh, T. R.; Drake, A. J.; Dhillon, V. S.; Littlefair, S. P.; Pyrzas, S.; Rebassa-Mansergas, A.; Schreiber, M. R.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 429, Issue 1, p.256-268
Advertised on:
2
2013
Citations
60
Refereed citations
56
Description
We analyse the Catalina Real-time Transient Survey light curves of 835
spectroscopically confirmed white dwarf plus main-sequence binaries from
the Sloan Digital Sky Survey (SDSS) with g < 19, in search of new
eclipsing systems. We identify 29 eclipsing systems, 12 of which were
previously unknown. This brings the total number of eclipsing white
dwarf plus main-sequence binaries to 49. Our set of new eclipsing
systems contains two with periods of 1.9 and 2.3 d, making them the
longest period eclipsing white dwarf binaries known. We also identify
one system which shows very large ellipsoidal modulation (almost 0.3
mag), implying that the system is both very close to Roche lobe overflow
and at high inclination. However, our follow-up photometry failed to
firmly detect an eclipse, meaning that either this system contains a
cool white dwarf and hence the eclipse is very shallow and undetectable
in our red-sensitive photometry or that it is non-eclipsing. Radial
velocity measurements for the main-sequence stars in three of our newly
identified eclipsing systems imply that their white dwarf masses are
lower than those inferred from modelling their SDSS spectra. 13
non-eclipsing post-common envelope binaries were also identified, from
either reflection or ellipsoidal modulation effects. The white dwarfs in
our newly discovered eclipsing systems span a wide range of parameters,
including low-mass (˜0.3 M⊙), very hot (80 000 K)
and a DC white dwarf. The spectral types of the main-sequence stars
range from M2 to M6. This makes our sample ideal for testing white dwarf
and low-mass star mass-radius relationships as well as close binary
evolution.