J. Patterson et al., RAPID OSCILLATIONS IN CATACLYSMIC VARIABLES - XIV - ORBITAL AND SPIN EPHEMERIDES OF FO AQUARII, Publications of the Astronomical Society of the Pacific, 110(746), 1998, pp. 415-419
Citations number
18
Categorie Soggetti
Astronomy & Astrophysics
Journal title
Publications of the Astronomical Society of the Pacific
We report on 17 years of photometry of FO Aquarii, a cataclysmic varia
ble with a rapidly rotating, magnetic white dwarf. We give ephemerides
for its variations at the 4.8 hr binary period and the 21 minute spin
period. The orbital period is constant at 0.2020596(1) day. The spin
period decreases on a timescale of 10(6) yr, but with additional wiggl
es on timescales of years to decades. The observed alternation between
spin-down and spin-up suggests that the star is near its equilibrium
spin period, an important prediction of the theory of magnetic catacly
smic variables.