XRISM measured gas plunging toward pulsar GX 301−2 at 540,000 km/h as it crossed Wray 977’s stellar wind—and found evidence that its turbulent disk breaks apart before rebuilding in the opposite direc

XRISM's iron-line spectrum directly measured plasma falling onto GX 301−2, while the disk-breakup and reversal sequence remains a model supported by spectra and Fermi timing.

Published September 21, 2026 · How we edit

XRISM recorded plasma falling towards the X-ray pulsar GX 301−2 at least 540,000 kilometres per hour while the neutron star passed through a dense stream in the wind of the blue hypergiant Wray 977.

The Japan-led observatory began observing BP Crucis on 1 February 2025, collecting about 16 hours of usable data near the end of a strong flare. Resolve measured the gas’s motion and spectral changes that constrain its changing arrangement around the pulsar.

This is one observation of one flare. The direct result is spectroscopic evidence for inflow. Disk breakup and reversal are interpretations drawn from XRISM spectra, long-term Fermi timing and flow modelling, not frames from a resolved image.