Abstract
We report on XMM-Newton observations performed on 2001 September 13-14 of the neutron star X-ray transient KS 1731-260 in quiescence. The source was detected at an unabsorbed 0.5-10 keV flux of only (4-8) x 10(-14) ergs cm(-2) s(-1), depending on the model used to fit the data, which for a distance of 7 kpc implies a 0.5-10 keV X-ray luminosity of approximately (2-5) x 10(32) ergs s(-1). The 2001 September quiescent flux of KS 1731-260 is lower than that observed during the Chandra observation in 2001 March. In the cooling neutron star model for the quiescent X-ray emission of neutron star X-ray transients, this decrease in the quiescent flux implies that the crust of the neutron star in KS 1731-260 cooled down rapidly between the two epochs, indicating that the crust has a high conductivity. Furthermore, enhanced cooling in the neutron star core is also favored by our results.
| Original language | English |
|---|---|
| Pages (from-to) | pp.L45-L49. |
| Number of pages | 5 |
| Journal | Astrophysical Journal |
| Volume | 573 |
| Issue number | 1 |
| Publication status | Published - 1 Jul 2002 |
Keywords
- accretion, accretion disks
- stars : individual (KS 1731-260)
- X-rays : stars
- ASCA OBSERVATIONS
- KS-1731-260
- BURSTER
- NOVAE
- MODEL