SN 2013fs is a supernova, located in the spiral galaxyNGC 7610, discovered by the Intermediate Palomar Transient Factory sky survey at Palomar Observatory in October 2013 (and originally named iPTF 13dqy).[3] It was discovered approximately three hours from explosion (first light) and was observed in ultraviolet and X-ray wavelengths, among others, within several hours.[2] Optical spectra were obtained beginning at six hours from explosion, making these the earliest such detailed observations ever made of a supernova.[2]
The star that produced SN 2013fs was a red supergiant with a mass 10 times the mass of the Sun, an effective temperature of 3,500 K, a radius 607[4] times the size of the Sun, and no more than a few million years old when it exploded.[2] The star was surrounded by a relatively dense shell of gas shed by the star within the year before it exploded.[3] Radiation emitted by the supernova explosion illuminated this shell, which had a mass of approximately one-thousandth the mass of the Sun, and its outer fringe was about five times the distance of Neptune from the Sun.[2]
^ abYaron, O.; Perley, D. A.; Gal-Yam, A.; Groh, J. H.; Horesh, A.; Ofek, E. O.; Kulkarni, S. R.; Sollerman, J.; Fransson, C.; Rubin, A.; Szabo, P.; Sapir, N.; Taddia, F.; Cenko, S. B.; Valenti, S.; Arcavi, I.; Howell, D. A.; Kasliwal, M. M.; Vreeswijk, P. M.; Khazov, D.; Fox, O. D.; Cao, Y.; Gnat, O.; Kelly, P. L.; Nugent, P. E.; Filippenko, A. V.; Laher, R. R.; Wozniak, P. R.; Lee, W. H.; et al. (2017). "Confined dense circumstellar material surrounding a regular type II supernova". Nature Physics. 13 (5): 510. arXiv:1701.02596. Bibcode:2017NatPh..13..510Y. doi:10.1038/nphys4025. S2CID29600801.