(cba:news) cba preprint - v803 cen
jk at cbastro.org
Mon Dec 13 12:44:18 EST 1999
A new CBA Preprint on V803 Centauri can now be found on the publications
page of the CBA web site.
V803 Centauri, A Helium-Rich Dwarf Nova
Joseph Patterson, Stan Walker, Jonathan Kemp, Darragh O'Donoghue, and Marc Bos
Publications of the Astronomical Society of the Pacific
(submitted, December 1999)
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 0.98 d. 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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