2002ApJ...567L..49T

We present spectroscopy and time series photometry of the newly discovered dwarf nova 1RXS J232953.9+062814. Photometry in the superoutburst reveals a superhump with a period of 66.06(6) minutes. The low-state spectrum shows Balmer and He I emission on a blue continuum and, in addition, a rich absorption spectrum of type K4±2. The absorption velocity is modulated sinusoidally at P_orb=64.176(5) minutes, with semiamplitude of K=348(4) km.s^–1. The low-state light curve is double humped at this period and is phased as expected for ellipsoidal variations. The absorption strength does not vary appreciably around the orbit. The orbital period is shorter than any other cataclysmic variable save for a handful of helium-star systems and V485 Centauri (59 minutes). The secondary is much hotter than main-sequence stars of similar mass, but it is well matched by helium-enriched models, indicating that the secondary evolved from a more massive progenitor. A preliminary calculation in which a 1.2 M_☉ star begins mass transfer near the end of hydrogen burning matches this system's characteristics remarkably well.