NASA and JAXA’s XRISM observatory has directly detected a giant star’s wind falling onto its compact companion and powering strong X-ray flares. The target, the high-mass binary BP Crucis, lies about 13,000 light-years away. Its primary, Wray 977, is a blue hypergiant roughly 40 times the Sun’s mass, while GX 301-2 is a neutron-star pulsar about 20 kilometers across that rotates every 11 minutes.
XRISM observed the system for about 16 hours during a flare on February 1, 2025. Its Resolve instrument recorded highly detailed X-ray spectra, including redshifted iron absorption lines showing plasma moving toward the pulsar at around 540,000 kilometers per hour. The results reveal how the pulsar captures the stellar wind: a turbulent accretion disk forms, can break apart as the pulsar enters the densest stream, and may briefly reform with reverse rotation. The measurements provide a new way to test matter-accretion processes around neutron stars.
https://science.nasa.gov/missions/xrism/xrism-sees-pulsar-gathering-companions-wind/
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2026-09-18 18:55:43 UTC
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npub1sxexewvzysc3affq4yzzh7w8e3udyujap2vlj7t6lkdg5dvhp24q4dz7z7Published at
2026-09-18 18:55:43 UTCEvent JSON
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"content": "NASA and JAXA’s XRISM observatory has directly detected a giant star’s wind falling onto its compact companion and powering strong X-ray flares. The target, the high-mass binary BP Crucis, lies about 13,000 light-years away. Its primary, Wray 977, is a blue hypergiant roughly 40 times the Sun’s mass, while GX 301-2 is a neutron-star pulsar about 20 kilometers across that rotates every 11 minutes.\n\nXRISM observed the system for about 16 hours during a flare on February 1, 2025. Its Resolve instrument recorded highly detailed X-ray spectra, including redshifted iron absorption lines showing plasma moving toward the pulsar at around 540,000 kilometers per hour. The results reveal how the pulsar captures the stellar wind: a turbulent accretion disk forms, can break apart as the pulsar enters the densest stream, and may briefly reform with reverse rotation. The measurements provide a new way to test matter-accretion processes around neutron stars.\n\nhttps://science.nasa.gov/missions/xrism/xrism-sees-pulsar-gathering-companions-wind/",
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