The fading of the extraordianry low-mass X-ray binary EXO 0748-676: Part III

We propose to continue monitoring the dipping lowmass Xray binary EXO 0748676as it moves into quiescence. RXTE first reported the detection of EXO 0748676at the lowest flux level since the beginning of the RXTE mission in 1996 inpointed observations during August 2008. Swift observations in October 2008confirmed the likely cessation of accretion activity. The cooling of the neutronstar (NS) crust has been subsequently monitored with XMM observations (thisproposal, Parts I and II). The last of these observations in June 2010 showedthat the crust and core were very close to reach thermal equilibrium. A furtherobservation of EXO 0748676 will allow us to continue the monitoring of thecooling curve of the NS crust and set up stringent constraints on the mass and radius of the NS. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]