Astronomers Use XRISM to Study Giant Star Outflow

The Japan-led XRISM observatory analyzes stellar winds from the blue hypergiant Wray 977 in BP Crucis.

Using data from the Japan-led XRISM observatory, astronomers have gained new insights into the outflow from a giant star, known as a stellar wind. This phenomenon is being captured by a compact companion star, contributing to NASA's exploration of the universe's extremes. The findings, published in Science Advances, target the BP Crucis system located about 13,000 light-years away. The primary star, Wray 977, is a blue hypergiant with 40 times the Sun's mass and 60 times its size, emitting a strong stellar wind. Its companion, the neutron star GX 301-2, is a pulsar that emits an X-ray beam toward Earth and produces strong flares during its 41.5-day orbit. Observations on February 1, 2025, using XRISM's Resolve instrument, captured detailed X-ray spectra over 16 hours.