Astronomers at Ohio State University are looking to use a recently launched NASA satellite to monitor massive explosions in space known as supernovae.
In a study featured in the journal Monthly Notices of the Royal Astronomical Society, OSU graduate student Patrick Vallely and his colleagues detailed how they were able to observe a supernova using NASA's Transiting Exoplanet Survey Satellite.
The results offered new insights regarding the nature of such a cosmic event and the different elements it often leaves behind.
Observing Supernovae
A supernova is a large explosion that typically takes place when a star reaches the end of its life cycle, according to NASA.
However, another type of supernova occurs in binary star systems, where two stars share a single point of orbit. One of these stars is often a carbon and oxygen rich white dwarf, which tends to steal matter from its companion star. Once the white dwarf manages to collect too much matter, it will trigger a massive explosion.
Observing supernovae from Earth has been difficult given that they often occur in distant galaxies. German astronomer Johannes Kepler made the last observation of a supernova in the Milky Way in 1604. This has limited scientists' understanding on what these cosmic events are.
To find out more about supernovae, Vallely and team developed a way on how to use TESS to identify and observe explosions in space. They focused their study on a supernova that involved a white dwarf star.
"We have known for years that these stars explode, but we have terrible ideas of why they explode," Vallely said.
White Dwarf Supernova
One particular question the OSU scientists had to answer was whether white dwarf supernovae leave behind traces of hydrogen, which is a key building block of stars and other bodies in the universe. By their nature, white dwarfs would have already burned through their supply of hydrogen. This would make them an unlikely source of the gas needed to trigger a supernova.
With the help of TESS, Vallely and his colleagues were able to identify hydrogen traces in the aftermath of a white dwarf supernova for the first time.
"The most interesting thing about this particular supernova is the hydrogen we saw in its spectra," Vallely said.
"We've been looking for hydrogen and helium in the spectra of this type of supernova for years—those elements help us understand what caused the supernova in the first place."
Initially, it was believed that the hydrogen may have come from the companion star, meaning that it was not a white dwarf itself. However, measurements of the light curve from the supernova the OSU scientists observed indicated that the second star was indeed a white dwarf.
Kris Stanek, an astronomer professor at OSU and coauthor of the study, said it is possible that the hydrogen was taken from a companion star that was not a white dwarf. However, he also theorizes that the gas may have come from another star that was near the exploding white dwarf. This third star may have been consumed in the ensuing supernova by chance.
While the researchers mostly agree that the companion star helps trigger a white dwarf supernova, they have yet to determine the exact mechanism of such a massive explosion. The makeup of the companion star also needs to be identified.
Stanek believes their research helps provide evidence that the companion star in such a supernova is most likely a white dwarf itself.
