V803 Centauri, A Helium-Rich Dwarf Nova

Joseph Patterson, Stan Walker, Jonathan Kemp, Darragh O'Donoghue, Marc Bos, and Rod Stubbings

Publications of the Astronomical Society of the Pacific

May 2000, Volume 112, Page 625

We report 1992-1999 photometry of the helium-rich cataclysmic variable V803 Centauri. In its high-brightness state at V=13, the star shows a strong periodic signal with P=1618 s; this resembles the superhumps associated with many dwarf novae. However, it is unusual because the superhump endures through all brightness states, including the very faint state at V=17. The star also becomes occasionally stuck in a "cycling state", in which the brightness varies in the range 13.4-14.5, with a period of 22±1 hr. This appears to be the recurrence pattern of "normal" dwarf-nova outbursts. Thus the underlying physics is probably that of a dwarf nova, but with an accretion disk dominated by helium.

Reckoned as a dwarf nova, V803 Cen presents an interesting test for accretion disk theory, because it appears to display two timescales for eruption recurrence: 0.94 d at V=14.5, and ~5 d at V=17.2. This is roughly consistent with the general idea that recurrence time scales inversely with accretion rate.

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Copyright © 2000 Astronomical Society of the Pacific.