Unique Type Ia Supernova With Hydrogen Emissions – Detected

Eddie Gonzales Jr. – MessageToEagle.com – A supernova with an unusual chemical signature was observed by astronomers using the Magellan telescopes at Carnegie’s Las Campanas Observatory in Chile.

Astronomers detected the emission of hydrogen that makes this supernova, called ASASSN-18tb, so unique.

ype Ia supernova with hydrogen emissions

Type Ia supernovae play a crucial role in helping astronomers understand the universe and their extraordinary brilliance make them visible across great distances and to be used as cosmic mile-markers.

Although hydrogen is the most-abundant element in the universe, it is almost never seen in Type Ia supernova explosions. In fact, the lack of hydrogen is one of the defining features of this category of supernovae and is thought to be a key clue to understanding what came before their explosions.

This is why seeing hydrogen emissions coming from this supernova was so surprising.

Type Ia supernovae originate from the thermonuclear explosion of a white dwarf that is part of a binary system. But the great puzzle is: what exactly triggers the explosion of the white dwarf (the dead core left after a Sun-like star exhausts its nuclear fuel).

A prevailing idea is that, the white dwarf gains matter from its companion star, a process that may eventually trigger the explosion, but whether this is the correct theory has been hotly debated for decades.

In recent years, astronomers have discovered a small number of rare Type Ia supernovae that are cloaked in large amount of hydrogen—maybe as much as the mass of our Sun. But in several respects, ASASSN-18tb is special.

“It’s possible that the hydrogen we see when studying ASASSN-18tb is like these previous supernovae, but there are some striking differences that aren’t so easy to explain,” Juna Kollmeier from Carnegie Institution for Science, said in a press release.

In all previous cases these hydrogen-cloaked Type Ia supernovae were found in young, star-forming galaxies where plenty of hydrogen-rich gas may be present. But ASASSN-18tb occurred in a galaxy consisting of old stars. Second, the amount of hydrogen ejected by ASASSN-18tb is significantly less than that seen surrounding those other Type Ia supernovae. It probably amounts to about one-hundredth the mass of our Sun.

“One exciting possibility is that we are seeing material being stripped from the exploding white dwarf’s companion star as the supernova collides with it,” said Carnegie’s Anthony Piro.

“If this is the case, it would be the first-ever observation of such an occurrence.”

Paper

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff Writer