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Astron. Astrophys. 357, 527-532 (2000)

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Observations of Eddington-limited type-I X-ray bursts from 4U 1812-12

M. Cocchi 1, A. Bazzano 1, L. Natalucci 1, P. Ubertini 1, J. Heise 2, E. Kuulkers 2,3, J.M. Muller 2,4 and J.J.M. in 't Zand 2

1 Istituto di Astrofisica Spaziale (IAS/CNR ), Via Fosso del Cavaliere 100, 00133 Roma, Italy
2 Space Research Organization Netherlands (SRON) , Sorbonnelaan 2, 3584 TA, Utrecht, The Netherlands
3 Astronomical Institute, Utrecht University, P.O. Box 80000, 3507 TA, Utrecht, The Netherlands
4 BeppoSAX Science Data Centre, Nuova Telespazio, Via Corcolle 19, 00131 Roma, Italy

Received 24 December 1999 / Accepted 13 March 2000


During more than 3 years (August 1996-October 1999) monitoring of a [FORMULA] sky region around the Galactic Centre by the Wide Field Cameras on board BeppoSAX , a total of 8 type-I bursts have been detected from a sky position consistent with that of 4U 1812-12, a likely neutron-star low-mass X-ray binary. We present the results of a detailed study of the bursts of 4U 1812-12, about 15 years after the last reported observations of X-ray bursts from this source (Murakami et al. 1983). Clear evidence for photospheric radius expansion due to Eddington-limited burst luminosity is present in most of the observed events, allowing an accurate estimate of the source distance ([FORMULA] kpc) and its burst parameters.

Key words: stars: binaries: general – stars: novae, cataclysmic variables – stars: individual: 4U 1812 – 12 – X-rays: bursts – X-rays: stars

Send offprint requests to: M. Cocchi (wood@ias.rm.cnr.it)

© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000