2010MNRAS.409..237U -
Mon. Not. R. Astron. Soc., 409, 237-246 (2010/November-3)
The orbital period and system parameters of the recurrent nova T Pyx.
UTHAS H., KNIGGE C. and STEEGHS D.
Abstract (from CDS):
T Pyx is a luminous recurrent nova that accretes at a much higher rate than is expected for its photometrically determined orbital period of about 1.8 h. We here provide the first spectroscopic confirmation of the orbital period, P = 1.8295h (f = 13.118368±1.1x10–5/cd), based on time-resolved optical spectroscopy obtained at the Very Large Telescope and the Magellan telescope. We also derive an upper limit of the velocity semi-amplitude of the white dwarf, K1 = 17.9±1.6 km/s, and estimate a mass ratio of q = 0.20±0.03. If the mass of the donor star is estimated using the period-density relation and theoretical main-sequence mass-radius relation for a slightly inflated donor star, we find M2= 0.14 ± 0.03 M☉. This implies a mass of the primary white dwarf of M1 = 0.7±0.2 M☉. If the white-dwarf mass is >1M☉, as classical nova models imply, the donor mass must be even higher. We therefore rule out the possibility that T Pyx has evolved beyond the period minimum for cataclysmic variables. We find that the system inclination is constrained to be i ~ 10°, confirming the expectation that T Pyx is a low-inclination system. We also discuss some of the evolutionary implications of the emerging physical picture of T Pyx. In particular, we show that epochs of enhanced mass transfer (like the present) may accelerate or even dominate the overall evolution of the system, even if they are relatively short-lived. We also point out that such phases may be relevant to the evolution of cataclysmic variables more generally.
Abstract Copyright:
© 2010 The Authors. Journal compilation © 2010 RAS
Journal keyword(s):
stars: individual: T Pyx - novae, cataclysmic variables
Simbad objects:
3
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