A superburst from 4U 1254-690
Abstract
We report the detection with the BeppoSAX Wide Field Cameras of a superburst from 4U 1254-690. 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.
Cite
@article{arxiv.astro-ph/0310364,
title = {A superburst from 4U 1254-690},
author = {J. J. M. in 't Zand and E. Kuulkers and F. Verbunt and J. Heise and R. Cornelisse},
journal= {arXiv preprint arXiv:astro-ph/0310364},
year = {2009}
}
Comments
Accepted by A&A Letters