Early 56 Ni decay gamma rays from SN2014J suggest an unusual explosion

Abstract

Surprise found by γ-ray metal detector Astronomers commonly use type-Ia supernovae as standard distance measurement tools, though the physics of these bright sources are not fully understood. One product of the thermonuclear explosion is 56 Ni, which probably lies at the heart of the supernova cloud. Diehl et al. detected the gamma-ray emission from 56 Ni in SN2014J much earlier than expected, only about 20 days after the initial explosion. This early exposure suggests both an asymmetric event and the production of 56 Ni farther out in the ejecta than predicted. These sources will help astronomers measure distances far beyond where supernovae have been studied. Science , this issue p. 1162