The very short supersoft X-ray state of the classical nova M31N 2007-11a
Della Valle, M.; Pietsch, W.; Haberl, F.; Burwitz, V.; Greiner, J.; Henze, M.; Hernanz, M.; Sala, G.; Hartmann, D. H.; Freyberg, M. J.; Milne, P.; Williams, G. G.
Germany, Spain, Italy, United States
Abstract
Context: Short supersoft X-ray source (SSS) states (durations ≤100 days) of classical novae (CNe) indicate massive white dwarfs that are candidate progenitors of supernovae type Ia.
Aims: We carry out a dedicated optical and X-ray monitoring program of CNe in the bulge of M 31.
Methods: We discovered M31N 2007-11a and determined its optical and X-ray light curve. We used the robotic Super-LOTIS telescope to obtain the optical data and XMM-Newton and Chandra observations to discover an X-ray counterpart to that nova.
Results: Nova M31N 2007-11a is a very fast CN, exhibiting a very short SSS state with an appearance time of 6-16 days after outburst and a turn-off time of 45-58 days after outburst.
Conclusions: The optical and X-ray light curves of M31N 2007-11a suggest a binary containing a white dwarf with M_WD > 1.0 Msun.