Scientists have observed two massive explosions in far off outer space.
A research team detected a Type Ib supernova, which are "rare explosions where the progenitor star lacks an outer layer of hydrogen, the most abundant element in the universe, a California Institute of Technology news release reported.
Scientists aren't sure what type of stars tends to morph into these a Type Ib supernova. One theory suggests they form from Wolf-Rayet stars, which are thousands of times more massive and 10 times brighter than our own Sun. They are characterized by a loss of hydrogen through stellar winds.
There is little evidence to prove this theory, but the explosion took place in a region believed to have once held a Wolf-Rayet.
A team spotted Supernova iPTF13bvn less than a full day after the explosion, the team was able to get a clear photograph of the supernova and pinpoint its exact location. After comparing images the Hubble Space telescope took several years ago, the team determined the supernova had characteristics of a Wolf-Rayet.
"All evidence is consistent with the theoretical expectation that the progenitor of this Type Ib supernova is a Wolf-Rayet star," lead author of the study Yi Cao, said. "Our next step is to check for the disappearance of this progenitor star after the supernova fades away. We expect that it will have been destroyed in the supernova explosion."
The paper is titled "Discovery, Progenitor and Early Evolution of a Stripped Envelope Supernova iPTF13bvn," appears Astrophysical Journal Letters.
A second study observed the afterglow of a long gamma-ray burst (GRB), finding this phenomenon was compared to "digging a needle out of a haystack."
These Long GRBs are associated with the death of "rapidly spinning stars," and are the brightest-known events in the universe.
After searching painstakingly searching for the object, and succeeding in finding it, the team watched the glow fade over a period of a few days and saw a supernova form five days later.
"First, by measuring its redshift, we learned that it was pretty nearby as far as GRBs go," Lead author Leo Singer, a Caltech grad student, said. "It was pretty wimpy compared to most GRBs, liberating only about a thousandth as much energy as the most energetic ones. But we did see it eventually turn into a supernova. Typically we only detect supernovae in connection with nearby, subluminous GRBs, so we can't be certain that cosmologically distant GRBs are caused by the same kinds of explosions."
"The first results from iPTF bode well for the discovery of many more supernovae in their infancy and many more afterglows from the Fermi satellite," Shrinivas Kulkarni, the John D. and Catherine T. MacArthur Professor of Astronomy and Planetary Science at Caltech and principal investigator for both the PTF and iPTF, said.
