Parsons, S. G.; Hermes, J. J.; Marsh, T. R.; Gänsicke, B. T.; Tremblay, P.-E.; Littlefair, S. P.; Sahman, D. I.; Ashley, R. P.; Green, M.; Rattanasoon, S.; Dhillon, V. S.; Burleigh, M. R.; Casewell, S. L.; Buckley, D. A. H.; Braker, I. P.; Irawati, P.; Dennihy, E.; Rodríguez-Gil, P.; Winget, D. E.; Winget, K. I.; Bell, Keaton J.; Kilic, Mukremin
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 1, p.976-986
Description
Using data from the extended Kepler mission in K2 Campaign 10, we
identify two eclipsing binaries containing white dwarfs with cool
companions that have extremely short orbital periods of only 71.2 min
(SDSS J1205-0242, a.k.a. EPIC 201283111) and 72.5 min (SDSS J1231+0041,
a.k.a. EPIC 248368963). Despite their short periods, both systems are
detached with small, low-mass companions, in one case a brown dwarf and
in the other case either a brown dwarf or a low-mass star. We present
follow-up photometry and spectroscopy of both binaries, as well as
phase-resolved spectroscopy of the brighter system, and use these data
to place preliminary estimates on the physical and binary parameters.
SDSS J1205-0242 is composed of a 0.39 ± 0.02 M⊙
helium-core white dwarf that is totally eclipsed by a 0.049 ±
0.006 M⊙ (51 ± 6MJ) brown-dwarf
companion, while SDSS J1231+0041 is composed of a 0.56 ± 0.07
M⊙ white dwarf that is partially eclipsed by a companion
of mass ≲0.095 M⊙. In the case of SDSS J1205-0242,
we look at the combined constraints from common-envelope evolution and
brown-dwarf models; the system is compatible with similar constraints
from other post-common-envelope binaries, given the current parameter
uncertainties, but has potential for future refinement.
Related projects
The study of binary stars is essential to stellar astrophysics. A large number of stars form and evolve within binary systems. Therefore, their study is fundamental to understand stellar and galactic evolution. Particularly relevant is that binary systems are still the best source of precise stellar mass and radius measurements. Research lines
Black holes, neutron stars, white dwarfs and their local environment
Accreting black-holes and neutron stars in X-ray binaries provide an ideal laboratory for exploring the physics of compact objects, yielding not only confirmation of the existence of stellar mass black holes via dynamical mass measurements, but also the best opportunity for probing high-gravity environments and the physics of accretion; the most
