Million-degree plasma pervading the extended Orion nebula

Most stars form as members of large associations within dense, very cold ( 10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars ( the Trapezium). We present x- ray observations obtained with the X- ray Multi- Mirror satellite XMM- Newton, revealing that a hot plasma with a temperature of 1.7 to 2.1 million kelvin pervades the southwest extension of the nebula. The plasma flows into the adjacent interstellar medium. This x- ray outflow phenomenon must be widespread throughout our Galaxy.