A candidate AM CVn system from CRTS
ATel #4678; A. J. Drake, S. G. Djorgovski, A. A. Mahabal, M. J. Graham, R. Williams (Caltech); J. Prieto (Princeton); M. Catelan (PUC Chile); E. Christensen, S. M. Larson (LPL/UA)
on 24 Dec 2012; 19:23 UT
Credential Certification: Andrew J. Drake (ajd@cacr.caltech.edu)
Subjects: Optical, Cataclysmic Variable, Transient, Variables
Here we report the CRTS discovery of candidate AM CVn system
CSS121123:045020-093113. This source was discovered on 2012-11-23
in data from the Catalina Survey Schmidt telescope and was
classified as a likely cataclysmic variable based on the large
outburst amplitude (~ 5mags) and the presence of an apparent point
source in prior DSS and ESO images. No prior outbursts are seen in
six years of prior Catalina observations. The source was reobserved
by CSS on 2012-12-04 and found to have faded to its pre-outburst
level (V~20.5).
The object was observed with the Keck-I+LRIS on Dec 16th UT in
poor seeing conditions. The noisy spectrum resembles the low-state
spectrum of SDSS J1240-01 with clear Helium emission lines as well
as nitrogen, yet no sign of Balmer emission or absorption features.
Photometric observations are required to determine the orbital period
of this system and confirm the nature of this source. If this is indeed
an AM CVn system, it is one of eight CVs discovered by CRTS below the
CV orbital period minimum. Given the small fraction (< 15%) of CRTS CVs
with known periods, these results suggest that there are more than a
dozen AM CVn systems among the ~700 CVs so far discovered by CRTS.
All CVs discovered by CRTS are publicly available via the CRTS
website.
