Modern telescopes such as Kepler have allowed researchers to study the stars much more closely than ever before. Supernovas have been of particular interest, both because they are important to our understanding of how stars work and because they are spectacular events.

It has long been suspected that large, hot, hydrogen deficient Wolf-Rayet stars explode as type IIb, Ib or Ic supernovae, but there hasn’t been direct evidence linking these types of supernovae to the stars that spawned them.

Recently, while observing a supernova, a team led by Avishay Gal-Yam of the Weizmann Institute of Science in Israel applied a new observation method. They used flash spectroscopy to identify the star that spawned the event. When the star exploded it ionized its immediate surroundings. This effect gives astronomers only a day to make their observations.

“This supernova was discovered by the Palomar 48-inch telescope in California. The on-duty PTF team member in Israel promptly sounded an alert about this supernova discovery enabling another PTF team member to get a spectrum with the Keck telescope before the sun rose in Hawaii. The global rapid response protocol ensures the sun never rises for the PTF team,” Carnegie Institution’s Mansi Kasliwal explained in a statement.

Their observations confirmed, based on the composition and shape of the supernova, that a Wolf-Rayet star was the progenitor of the event.

The study of supernova SN 2013cu, published in the journal Nature, confirms that Wolf-Raynet stars generate type IIb supernovae. It will also help astronomers to more closely observe future events, by watching Wolf-Raynet stars for signs that they are reaching the end of their lives.