A star has exploded in a galaxy just 21 million light years from Earth, giving astronomers a rare opportunity to watch a supernova unfold in real time in exquisite detail.
Supernova SN 2023ixf was discovered in the Pinwheel galaxy, or M101, on 19 May by a Japanese amateur astronomer called Koichi Itagaki. It is the closest supernova to Earth since SN 2014J in 2014, which was some 11 million light years away. The supernova, which already outshines its host galaxy, is expected to peak in brightness in the coming days, but may remain visible for years.
While thousands of supernovae are seen every year, the proximity of 2023ixf means it can be studied in much more detail than others. Telescopes across the world were trained in its direction “within hours of its discovery”, says Azalee Bostroem at the University of Arizona, deducing it was probably a type II supernova, in which a supergiant star runs out of fuel and collapses in on itself before exploding.
Bostroem has been allocated time on the Hubble Space Telescope to study the ultraviolet light from the explosion. So far, it looks like the supernova is interacting with material that was previously ejected by the star, which the Hubble observations could probe further. “How stars lose mass is one of the most interesting questions,” says Bostroem.
Two or three stars have been identified as the possible progenitor of the supernova, including a type of massive star known as a Wolf-Rayet star, but the supernova is currently too bright to work out which it is. Hubble or even the James Webb Space Telescope could tell us more when the supernova dims.
Observations of 2023ixf may provide invaluable data on our understanding of how supernovae unfold. “This is going to be like a Rosetta Stone supernova,” says Bostroem. “It’s going to be one of those ones that we compare everything to.”