GALEX J194419.33+491257.0: An unusually active SU UMa-type dwarf nova with a very short orbital period in the Kepler data
Abstract
We studied a background dwarf nova of KIC 11412044 in the Kepler public data and identified it with GALEX J194419.33+491257.0. This object turned out to be a very active SU UMa-type dwarf nova that has a mean supercycle of ∼ 150 d and frequent normal outbursts with intervals of 4-10 d. The object showed a strong persistent signal of the orbital variation with a period of 0.0528164(4) d (76.06 min) and superhumps with a typical period of 0.0548 d during its superoutbursts. Most of the superoutbursts were accompanied by a precursor outburst. All these features are unusual for this very short orbital period. We succeeded in detecting an evolving stage of superhumps (stage A superhumps) and obtained a mass ratio of 0.141(2), which is unusually high for this orbital period. We suggest that the unusual outburst properties are a result of this high mass ratio. We suspect that this object is a member of the recently recognized class of cataclysmic variables (CVs) with a stripped core evolved secondary which are evolving toward AM CVn-type CVs. The present determination of the mass ratio by using stage A superhumps is the first case in such systems.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- April 2014
- DOI:
- 10.1093/pasj/psu025
- arXiv:
- arXiv:1403.0308
- Bibcode:
- 2014PASJ...66L...5K
- Keywords:
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- accretion;
- accretion disks;
- novae;
- cataclysmic variables;
- stars: dwarf novae;
- stars: individual (GALEX J194419.33+491257.0);
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 6 pages, 5 figures, accepted for publication in PASJ