Two new Double-lined Spectroscopic Binary White Dwarfs. (arXiv:2002.06214v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kilic_M/0/1/0/all/0/1">Mukremin Kilic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bedard_A/0/1/0/all/0/1">A. Bedard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bergeron_P/0/1/0/all/0/1">P. Bergeron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kosakowski_A/0/1/0/all/0/1">Alekzander Kosakowski</a>
We present radial velocity observations of four binary white dwarf candidates
identified through their over-luminosity. We identify two new double-lined
spectroscopic binary systems, WD 0311-649 and WD 1606+422, and constrain their
orbital parameters. WD 0311-649 is a 17.7 h period system with a mass ratio of
$1.44 pm 0.06$ and WD 1606+422 is a 20.1 h period system with a mass ratio of
$1.33 pm 0.03$. An additional object, WD 1447-190, is a 43 h period
single-lined white dwarf binary, whereas WD 1418-088 does not show any
significant velocity variations over timescales ranging from minutes to
decades. We present an overview of the 14 over-luminous white dwarfs that were
identified by Bedard et al., and find the fraction of double- and single-lined
systems to be both 31%. However, an additional 31% of these over-luminous white
dwarfs do not show any significant radial velocity variations. We demonstrate
that these must be in long-period binaries that may be resolved by Gaia
astrometry. We also discuss the over-abundance of single low-mass white dwarfs
identified in the SPY survey, and suggest that some of those systems are also
likely long period binary systems of more massive white dwarfs.
We present radial velocity observations of four binary white dwarf candidates
identified through their over-luminosity. We identify two new double-lined
spectroscopic binary systems, WD 0311-649 and WD 1606+422, and constrain their
orbital parameters. WD 0311-649 is a 17.7 h period system with a mass ratio of
$1.44 pm 0.06$ and WD 1606+422 is a 20.1 h period system with a mass ratio of
$1.33 pm 0.03$. An additional object, WD 1447-190, is a 43 h period
single-lined white dwarf binary, whereas WD 1418-088 does not show any
significant velocity variations over timescales ranging from minutes to
decades. We present an overview of the 14 over-luminous white dwarfs that were
identified by Bedard et al., and find the fraction of double- and single-lined
systems to be both 31%. However, an additional 31% of these over-luminous white
dwarfs do not show any significant radial velocity variations. We demonstrate
that these must be in long-period binaries that may be resolved by Gaia
astrometry. We also discuss the over-abundance of single low-mass white dwarfs
identified in the SPY survey, and suggest that some of those systems are also
likely long period binary systems of more massive white dwarfs.
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