Ed Cackett reviewed the existing data, and described the coming data, regarding observed cooling of the long-duration transients MXB 1659-29 and KS 1731-260. These are two post-outburst low mass X-ray binaries of great interest to observers and theorists, because the total magnitude of accretion over their outbursts is high enough to cause an energy deposit in the crust (due to Deep Crustal Heating) of such magnitude that it will heat the crust out of thermal equilibrium out of the core. Seven observations of the cooling crust have taken place; more have been approved, and will be made in the near future -- so stay tuned for new observational results. Up to now, these objects have continued a monotonic decrease in their emission temperature, consistent with the expectations of neutron star crustal cooling theory -- although interestingly different from the simple, early calculations of such cooling.
This talk informed the talk which followed, given by Ed Brown, in which Ed presented his (with Andrew Cumming) analysis of the observed cooling curves of these two objects, using more detailed cooling calculations.
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Chandra observed KS 1731-260 this week....I've now performed a very preliminary analysis which seems to show that it is continuing to cool, following a simple power-law. You can find a figure from my website:
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