EDP Sciences
Free access
Volume 498, Number 2, May I 2009
Page(s) L13 - L16
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361/200811581
Published online 01 April 2009
A&A 498, L13-L16 (2009)
DOI: 10.1051/0004-6361/200811581


The very short supersoft X-ray state of the classical nova M31N 2007-11a

M. Henze1, W. Pietsch1, G. Sala2, M. Della Valle3, 4, 5, M. Hernanz6, J. Greiner1, V. Burwitz1, M. J. Freyberg1, F. Haberl1, D. H. Hartmann7, P. Milne8, and G. G. Williams8

1  Max-Planck-Institut für extraterrestrische Physik, 85748 Garching, Germany
    e-mail: mhenze@mpe.mpg.de
2  Departament de Física i Enginyeria Nuclear, EUETIB (UPC/IEEC), Comte d'Urgell 187, 08036 Barcelona, Spain
3  European Southern Observatory (ESO), 85748 Garching, Germany
4  INAF - Napoli, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy
5  International Centre for Relativistic Astrophysics, Piazzale della Repubblica 2, 65122 Pescara, Italy
6  Institut de Ciències de l'Espai (CSIC-IEEC), Campus UAB, Fac. Ciències, 08193 Bellaterra, Spain
7  Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978, USA
8  Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA

Received 23 December 2008 / Accepted 13 March 2009

Context. Short supersoft X-ray source (SSS) states (durations $\le$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 $M_{\rm WD}$ > 1.0 $M_{\sun}$.

Key words: galaxies: individual: M31 -- novae, cataclysmic variables -- stars: individual: nova M31N 2007-11a  -- X-rays: galaxies

© ESO 2009