The detection of the Type Ia supernova SN 2020eyj at radio wavelengths show that the exploded white dwarf had a helium-rich companion. An artist’s rendition of SN 2020eyj, a white dwarf star that went supernova after pulling material from a helium companion star. Image credit: Adam Makarenko / W.M. Keck Observatory. Type Ia supernovae are important for astronomers since they are used to measure the expansion of the Universe. However, the origin...
