XRISM observatory captures stellar wind falling onto a pulsar

Astronomers using the NASA-JAXA XRISM observatory have captured the first direct observation of stellar wind plasma falling onto a compact neutron star. The discovery focuses on the high-mass X-ray binary system BP Crucis, located approximately 13,000 light-years away in the constellation Crux.

The system consists of a blue hypergiant star, Wray 977, and a neutron star pulsar, GX 301-2. Wray 977 is roughly 40 times the mass of the Sun and 60 times its diameter, emitting a continuous stream of ionized gas known as stellar wind. As the pulsar orbits the hypergiant every 41.5 days, its gravity captures this material, triggering powerful X-ray flares.

Using XRISM’s spectroscopic capabilities, researchers identified iron-rich plasma moving toward the neutron star at speeds of approximately 540,000 kilometers per hour. The data provides new insights into the accretion mechanics that drive high-energy outbursts in binary star systems.