Type 1a supernovae may form from dead stars that briefly come back to life in a brilliant flash of light.
Cobalt-56 was detected during one of these supernova explosions, lending evidence to one hypothesized model for the events.
Moscow Institute of Physics and Technology (MIPT) investigators found the element using the INTEGRAL gamma-ray orbital telescope. This vehicle, designed and managed by the European Space Agency (ESA), was launched into orbit in 2002. It is the most sensitive gamma ray telescope ever launched into space.
This isotope of cobalt is created in large quantities during powerful stellar explosions. With a half-life of just 77 days, the material quickly decays into other elements, making it nearly non-existent in nature.
Supernova SN2014J was first discovered on 21 January 2014 by a team headed by astronomer Steve Fossey from the University College London. The stellar bodies lie in the galaxy M82, roughly 11.4 million light years from Earth.
Astronomers studying SN2014J believe the explosion of the supernova released an amount of cobalt-56 equal to 60 percent of the mass of the Sun.
"Over time, cobalt-56 turns into the most common isotope of iron. [Iron-56] is the most common isotope because it can be obtained from nickel emitted during supernovae explosions (nickel turns into cobalt, and cobalt turns into iron)," MIPT researchers reported.
Type 1a supernovas are fairly common, with one such event seen ever few hundred years in a typical galaxy. These regular events are used by astronomers as a "standard candle" to measure the distance to far-flung galaxies.
White dwarfs are cool stellar corpses, devoid of nuclear fuel that once burned within the star. When found in binary systems with a massive partner, gas can drift off the larger companion and envelope the compact companion. When this material reaches a critical mass, the gas can suddenly ignite in a massive nuclear blast. The explosion would cast off nickel, iron and cobalt atoms, along with massive amounts of gamma ray radiation. This energy is quickly dispersed to space, and this was the first time the phenomenon has been observed in space.
Astronomers developed this theory of how Type 1a supernovae form long ago, but this new discovery is the first direct evidence for the idea.
"The importance of this discovery is not because something new/unknown was discovered, but we had an observation of a long-standing theory that had no real evidence," Brad Tucker, of the University of California Berkeley and the Australian National University, said.
Discovery of cobalt in the observed supernova and investigation into the role played by the element on Type 1a supernovae was detailed in the journal Nature.
