The XMM-Newton view of the yellow hypergiant IRC + 10420 and its surroundings *

摘要

Among evolved massive stars likely in transition to the Wolf-Rayet phase, IRC + 10420 is probably one of the most enigmatic. It belongs to the category of yellow hypergiants and it is characterized by quite high mass loss episodes. Even though IRC + 10420 benefited of many observations in several wavelength domains, it has never been a target for an X-ray observatory. We report here on the very first dedicated observation of IRC + 10420 in X-rays, using the XMM-Newton satellite. Even though the target is not detected, we derive X-ray flux upper limits of the order of 1-3 × 10~(-14) erg cm~(-2) s~(-1) (between 0.3 and 10.0 keV), and we discuss the case of IRC + 10420 in the framework of emission models likely to be adequate for such an object. Using the Optical/UV Monitor on board XMM-Newton, we present the very first upper limits of the flux density of IRC + 10420 in the UV domain (between 1800 and 2250 ? and between 2050 and 2450 ?). Finally, we also report on the detection in this field of 10 X-ray and 7 UV point sources, and we briefly discuss their properties and potential counterparts at longer wavelengths.