Magnetic White Dwarfs in the Two Micron All Sky Survey:
A Search for Candidate Binary Systems
J. W. Wellhouse (Harvey Mudd College)
D. W. Hoard (Spitzer Science Center, California Institute of Technology)
S. B. Howell (WIYN Observatory/NOAO)
S. Wachter (Spitzer Science Center, California Institute of Technology)
A. A. Esin (Harvey Mudd College)
Published in the Publications of the Astronomical Society of the Pacific, 2005, v.117, p.1378
(2005PASP..117.1378W).
ABSTRACT:
Our understanding of the formation and evolution of magnetic cataclysmic
variables from initially detached, post-common envelope binary stars
containing a magnetic white dwarf and a main sequence star is currently
poorly constrained due to the lack of observational identification of
the progenitor systems. Very few potential pre-cataclysmic variables
containing a magnetic white dwarf are known, compared with approximately 25%
of the cataclysmic variable population that contain magnetic white dwarfs.
We present the results of a search for candidate binary systems containing
a magnetic white dwarf, which utilized photometric data from the Two
Micron All Sky Survey (as well as Hubble Space Telescope and WIYN
Observatory follow-up data for several objects). Our target sample was
drawn primarily from the comprehensive list of magnetic white dwarfs by
Wickramasinghe & Ferrario, plus several recently identified objects
selected from the literature. Out of 51 2MASS detections, no convincing
binary candidates were found. However, six objects merit additional
observation to determine the origin of a small near-infrared excess that
could be attributed to a very low mass stellar or substellar companion.
An additional four white dwarfs are possibly at the centers of previously
unknown, and likely unresolved, planetary nebulae.
(Support for this research was provided by NASA under an ADP
grant issued through the Office of Space Science.)