London, May 22 (ANI): Scientists at Weizmann Institute of Science, in collaboration with others around the world, have identified a new type of exploding star, called supernova-a feat that could shed Light on the mysteries of the Universe.
Until now, scientists had only observed two basic kinds of supernovae, which are either hot, young giants that go out in a violent display as they collapse under their own weight, or old, dense, white dwarves that blow up in a thermonuclear explosion.
The new supernova appeared in telescope images in early January 2005, and scientists, seeing that it had recently begun the process of exploding, started collecting and combining data from different telescope sites around the world, measuring both the amount of material thrown off in the explosion and its chemical makeup.
But Dr. Avishay Gal-Yam, and colleagues around the world soon found that the new supernova did not fit either of the known patterns.
On the one hand, the amount of material hurled out from the supernova was too small for it to have come from an exploding giant.
In addition, its location, distant from the busy hubs where new stars form, implied that it was an older star that had had time to wander off from its birthplace.
On the other hand, its chemical makeup didn't match that commonly seen in the second type.
"It was clear that we were seeing a new type of supernova," Nature quoted Dr. Hagai Perets, the paper's lead author, as saying.
The scientists turned to computer simulations to see what kind of process could have produced such a result.
The common type of exploding white dwarf (a type Ia supernova) is mainly made up of carbon and oxygen, and the chemical composition of the ejected material reflects this.
The newly discovered supernova had unusually high levels of the elements calcium and titanium; these are the products of a nuclear reaction involving helium, rather than carbon and oxygen.
"We've never before seen a spectrum like this oneIt was clear that the unique chemical composition of this explosion held an important key to understanding it," said a co-author of the study.
The simulations suggest that a pair of white dwarves are involved; one of them stealing helium from the other. When the thief star's helium load rises past a certain point, the explosion occurs.
"The donor star is probably completely destroyed in the process, but we're not quite sure about the fate of the thief star," said Gal-Yam.
The scientists believe that several other previously observed supernovae might fit this pattern.
Their findings of the study appeared in Nature. (ANI)