X-ray emission from massive stars

Massive young stars are known to emit strong X-rays. Unlike the X-ray emission from lower mass stars, however, which arises in stellar photospheres, the X-rays from massive stars are thought to result from powerful shocks. Several kinds of shocks can be responsible, produced either by very strong winds driven by the star's radiation, by the head-on collision between winds that have been magnetically channeled by the star's magnetic field, or by wind collisions in a binary stellar system in which