A superburst from 4U 1254-69

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
Number of authors
5
IAC number of authors
0
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.
Type