Bibcode
in't Zand, J. J. M.; Kuulkers, E.; Verbunt, F.; Heise, J.; Cornelisse, R.
Bibliographical reference
Astronomy and Astrophysics, v.411, p.L487-L491 (2003)
Advertised on:
12
2003
Journal
Citations
63
Refereed citations
55
Description
We report the detection with the BeppoSAX Wide Field Cameras of a
superburst from 4U 1254-69. The superburst is preceded by a normal
type-I X-ray burst, has a decay time that is the longest of all eight
superbursts detected so far and a peak luminosity that is the lowest.
Like for the other seven superbursts, the origin is a well-known type-I
X-ray burster with a persistent luminosity level close to one tenth of
the Eddington limit. Based on WFC data of all persistently bright X-ray
bursters, the average rate of superbursts is 0.51+/-0.25 per year per
persistently bright X-ray burster. Some systems may have higher
superburst rates. For all superbursters, we present evidence for a pure
helium layer which is burnt in an unstable as well as a stable manner.