Overview
- The peer‑reviewed study published Tuesday in the Astrophysical Journal reanalyzed Chandra data from 2000–2014 and found multiple supernova remnants in M83 showed large X‑ray brightness changes instead of gradual fading.
- One clear case, SN 1957D, is plausibly brightening because the supernova debris is colliding with surrounding gas and dust, which produces stronger X‑ray emission.
- The authors propose that some variable sources are high‑mass X‑ray binaries formed when a companion star survived the explosion and began transferring mass onto a neutron star or black hole.
- An alternative explanation is fallback accretion, in which expelled material falls back onto the compact remnant and drives episodic X‑ray flares.
- Researchers found similar variable remnants in M51, but M83’s 15 million light‑year distance limits spectral and spatial detail, so deeper X‑ray and multiwavelength follow‑up will be needed to confirm how common each cause is and what it means for compact‑object and binary evolution.