X-rays from the Orion Trapezium

Abstract

Observations of the Orion Nebula region and the associated X-ray source 4U 0531-05 with the SAS 3 rotation modulation collimators are presented which yield a precise position for a small component of the X-ray source and limit the source to the immediate region of the Trapezium. The reported weighted position has an error radius of 35 arcsec (90% confidence) and lies 9 arcsec from Theta-1 Ori. A 2-11-keV X-ray luminosity of approximately 0.7 x 10 to the 33rd erg/s is inferred for a distance of 460 pc, along with a component diameter of less than 0.3 pc. The existence of an extended component with a diameter of 0.8 to 1.6 pc and a flux density about twice that of the small component is also suggested. Possible sources of the X-ray emission are considered for both components. It is concluded that the two components may be ramifications of the stellar winds emanating from the Trapezium stars and that the small component may simply be a cusp in the larger distribution rather than an independent source.