X-ray detection of an FU Ori event in early outburst phase

FU Ori objects (FUORs) are latetype premain sequence stars in a phase ofstrong accretion. The phenomenon is probably repetitive but with low frequency,so that only 14 objects are classified as confirmed FUORs, with wellmonitoredoptical/infrared lightcurves available. About 10 are classified as FUORscandidate. Their Xray properties (luminosity and temperature) are almostcompletely unconstrained. Given the strong interplay between accretion and Xrayemission throughout the premain sequence phase, probed by observations of TTauri stars, this represents an important observational gap. The recentdiscovery of a new FU Ori outburst, V900 Mon, yields a unique opportunity tomonitor in Xrays such an event from early on throughout its decadelong decay. We propose here for the initial 80 ksec pointing. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]