SN 2019qem’s modeled 9-solar-mass eruption

The fit places it two years before explosion; wind speed, gas shape and light production affect the estimate.

By GreenSpacealien EditorialPublished November 4, 20261 min read

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Survey field with a yellow circle, coordinate axes and a scale bar. — SN 2019qem’s reported position is circled in this Legacy Surveys field.Legacy Surveys / D. Lang (Perimeter Institute); figure: Majumdar et al. · SN 2019qem: decades of extreme mass loss before the explosion of a luminous, long-lived Type IIn supernovaLicense terms · CC BY 4.0. Figure cropped from the paper page, resized, and converted for web.View full image

Model result

An arXiv preprint submitted on 3 November 2026 analyzes SN 2019qem’s 2019 explosion. No journal acceptance is listed.[1]

Fast debris hitting gas shed earlier can power a supernova’s bright light. The authors model this collision and use widths of hydrogen lines to limit shock speed. Their preferred fit suggests about 9 solar masses were expelled roughly 2.2 years before core collapse.[1]

This history is modeled, not a directly seen eruption. Mass depends on gas speed and shape and on how much collision energy becomes light. The progenitor’s identity remains unknown.[1]