How does a pulsar gather stellar wind?
The XRISM observatory has provided the first direct observation of a pulsar gathering stellar wind plasma from a companion star. Located 13,000 light-years away in the BP Crucis system, the neutron star GX 301-2 orbits a blue hypergiant named Wray 977. Data shows the pulsar captures stellar wind plasma, which flows toward it at 335,000 mph to power X-ray flares.
The pulsar completes an orbit every 41.5 days, triggering X-ray flares twice during its path. As it enters a dense stream of plasma from the hypergiant, the gas initially forms a turbulent disk. Researchers discovered that as the pulsar moves deeper into the flow, this disk dissipates, causing the plasma to fall directly onto the neutron star.
Why is this pulsar observation important?
This study offers a rare, detailed look at wind-fed pulsar accretion, a process that was previously difficult to observe directly. By analyzing iron absorption lines in X-ray spectra, scientists identified the velocity and direction of the incoming gas. These findings allow researchers to test theoretical models of how compact objects interact with their stellar environments in extreme conditions.
