Two more candidate AM Canum Venaticorum (AM CVn) Binaries from the Sloan Digital Sky Survey
Date
2008-06Author
Anderson, Scott
Becker, Andrew
Haggard, Daryl
Prieto, Jose Luis
Knapp, Gillian
Sako, Masao
Halford, Kelly
Jha, Saurabh
Martin, Blake
Holtzman, Jon
Frieman, Joshua
Garnavich, Peter
Hayward, Suzanne
Ivezic, Zeljko
Mukadam, Anjum
Sesar, Branimir
Szkody, Paula
Malanushenko, Viktor
Richmond, Michael
Schneider, Donald
York, Donald
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Show full item recordAbstract
AM CVn systems are a select group of ultracompact binaries with the shortest
orbital periods of any known binary subclass; mass-transfer is likely from a
low-mass (partially-)degenerate secondary onto a white dwarf primary, driven
by gravitational radiation. In the past few years, the Sloan Digital Sky Survey
(SDSS) has provided five new AM CVns. Here we report on two further candidates
selected from more recent SDSS data. SDSS J1208+3550 is similar to
the earlier SDSS discoveries, recognized as an AM CVn via its distinctive spectrum
which is dominated by helium emission. From the expanded SDSS Data
Release 6 (DR6) spectroscopic area, we provide an updated surface density estimate
for such AM CVns of order 10−3
.
1 to 10−2
.
5 deg−2 for 15 < g < 20.5. In
addition, we present another new candidate AM CVn, SDSS J2047+0008, that
was discovered in the course of followup of SDSS-II supernova candidates. It
shows nova-like outbursts in multi-epoch imaging data; in contrast to the other
SDSS AM CVn discoveries, its (outburst) spectrum is dominated by helium absorption
lines, reminiscent of KL Dra and 2003aw. The variability selection of
SDSS J2047+0008 from the 300 deg2 of SDSS Stripe 82 presages further AM CVn
discoveries in future deep, multicolor, and time-domain surveys such as LSST.
The new additions bring the total SDSS yield to seven AM CVns thus far, a substantial
contribution to this rare subclass, versus the dozen previously known.