Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-07-19
Astronomy and Astrophysics
Astrophysics
Accepted for publicaton in ApJ letters, 13 September 2001
Scientific paper
10.1086/324378
After more than a decade of actively accreting at about a tenth of the Eddington critical mass accretion rate, the neutron-star X-ray transient KS 1731-260 returned to quiescence in early 2001. We present a Chandra/ACIS-S observation taken several months after this transition. We detected the source at an unabsorbed flux of ~2 x 10^{-13} erg/cm^2/s (0.5-10 keV). For a distance of 7 kpc, this results in a 0.5-10 keV luminosity of ~1 x 10^{33} erg/s and a bolometric luminosity approximately twice that. This quiescent luminosity is very similar to that of the other quiescent neutron star systems. However, if this luminosity is due to the cooling of the neutron star, this low luminosity may indicate that the source spends at least several hundreds of years in quiescence in between outbursts for the neutron star to cool. If true, then it might be the first such X-ray transient to be identified and a class of hundreds of similar systems may be present in the Galaxy. Alternatively, enhanced neutrino cooling could occur in the core of the neutron star which would cool the star more rapidly. However, in that case the neutron star in KS 1731-260 would be more massive than those in the prototypical neutron star transients (e.g., Aql X-1 or 4U 1608-52).
Lewin Walter H. G.
Markwardt Craig
Miller John Mcl.
van der Klis Michiel
Wijnands Rudy
No associations
LandOfFree
A Chandra observation of the long-duration X-ray transient KS 1731-260 in quiescence: too cold a neutron star? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Chandra observation of the long-duration X-ray transient KS 1731-260 in quiescence: too cold a neutron star?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Chandra observation of the long-duration X-ray transient KS 1731-260 in quiescence: too cold a neutron star? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-657270