Abstract
We present an activity and kinematic analysis of high proper motion white
dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which
are new identifications. To identify WD+dMs, we developed a UV-optical-IR color
criterion and conducted a spectroscopic survey to confirm each candidate
binary. For the newly identified systems, we fit the two components using model
white dwarf spectra and M dwarf template spectra to determine physical
parameters. We use H$\alpha$ chromospheric emission to examine the magnetic
activity of the M dwarf in each system, and investigate how its activity is
affected by the presence of a white dwarf companion. We find that the fraction
of WD+dM binaries with active M dwarfs is significantly higher than their
single M dwarf counterparts at early and mid spectral types. We corroborate
previous studies that find high activity fractions at both close and
intermediate separations. At more distant separations the binary fraction
appears to approach the activity fraction for single M dwarfs. Using derived
radial velocities and the proper motions, we calculate 3D space velocities for
the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large
vertical velocity dispersion, indicating a dynamically hotter population
compared to high proper motion samples of single M dwarfs. We compare the
kinematics for systems with active M dwarfs and those with inactive M dwarfs,
and find signatures of asymmetric drift in the inactive sample, indicating that
they are drawn from an older population.
Users
Please
log in to take part in the discussion (add own reviews or comments).