Astronomers just found helium in a supernova that—by definition—is supposed to have absolutely zero helium in it.
April 2, 2026
Original Paper
Traces of Helium Detected in Type Ic Supernova 2014L
arXiv · 2604.00158
The Takeaway
Type Ic supernovae are categorized specifically by the total absence of helium in their light signatures. By using deep-learning emulators, scientists found 'hidden' helium in the data, suggesting our basic classification system for how stars explode might be wrong.
From the abstract
The absence of helium features in optical spectra is one of the classification criteria for Type Ic supernovae (SNe Ic). However, it is highly debated whether helium is truly absent in ejecta or spectroscopically undetectable in the optical region. The near-infrared (NIR) region contains cleaner He lines that are less blended with other common ions in SNe Ic ejecta. We perform full spectral modeling on the near-peak-light optical and NIR spectra of the SN Ic 2014L to quantitatively constrain hel