Palomar Observatory
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...
in October 2013 (and originally named iPTF 13dqy). It was discovered approximately three hours from explosion (first light) and was observed in
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...
and
X-ray
X-rays (or rarely, ''X-radiation'') are a form of high-energy electromagnetic radiation. In many languages, it is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it in 1895 and named it ' ...
wavelengths, among others, within several hours. Optical spectra were obtained beginning at six hours from explosion, making these the earliest such detailed observations ever made of a supernova.
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 times the size of the Sun, and no more than a few million years old when it exploded. The star was surrounded by a relatively dense shell of gas shed by the star within the year before it exploded. 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
Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 time ...