Add to favourites
News Local and Global in your language
21st of November 2017

Science



Supernova Discovery Challenges Theories of How Certain Stars End Their Lives | Astronomy | Sci-News.com

An international team of astronomers led by Las Cumbres Observatory has found a remarkable object in a nearby galaxy: a star that exploded multiple times over a period of more than 50 years. The finding, published by the journal Nature, completely confounds existing knowledge of a star’s end of life.

Artist’s impression of a Type II supernova. Image credit: NASA / ESA / G. Bacon, STSci.

Artist’s impression of a Type II supernova. Image credit: NASA / ESA / G. Bacon, STSci.

The supernova in question, iPTF14hls, was detected in 2014 by the intermediate Palomar Transient Factory.

The light given off by the event was analyzed in order to understand the speed and chemical composition of the material ejected in the explosion.

This analysis indicated that iPTF14hls was what’s called a Type II-P supernova, and everything about the discovery seemed normal. Until, that is, a few months later when the supernova started getting brighter again.

Type II-P supernovae usually remain bright for about 100 days. But iPTF14hls remained bright for more than 600.

When astronomers went back and looked at archival data, they were astonished to find evidence of an explosion in 1954 at the same location.

This star somehow survived that explosion and exploded again in 2014.

“This supernova breaks everything we thought we knew about how they work,” said Dr. Iair Arcavi, a postdoctoral fellow at Las Cumbres Observatory and the University of California, Santa Barbara.

“It’s the biggest puzzle I’ve encountered in almost a decade of studying stellar explosions.”

An image taken by the Palomar Observatory Sky Survey reveals a possible explosion in the year 1954 at the location of iPTF14hls (left), not seen in a later image taken in 1993 (right). Supernovae are known to explode only once, shine for a few months and then fade, but iPTF14hls experienced at least two explosions, 60 years apart. Image credit: Arcavi et al.

An image taken by the Palomar Observatory Sky Survey reveals a possible explosion in the year 1954 at the location of iPTF14hls (left), not seen in a later image taken in 1993 (right). Supernovae are known to explode only once, shine for a few months and then fade, but iPTF14hls experienced at least two explosions, 60 years apart. Image credit: Arcavi et al.

Dr. Arcavi and colleagues calculated that the star that exploded was at least 50 times more massive than the Sun and probably much larger.

iPTF14hls may have been the most massive stellar explosion ever seen.

The size of this explosion could be the reason that our conventional understanding of the death of stars failed to explain this event.

According to the team, iPTF14hls may be the first example of a ‘Pulsational Pair Instability Supernova.’

“According to this theory, it is possible that this was the result of star so massive and hot that it generated antimatter in its core,” said Dr. Daniel Kasen, from the University of California, Berkeley, and Lawrence Berkeley Lab.

“That would cause the star to go violently unstable, and undergo repeated bright eruptions over periods of years.”

That process may even repeat over decades before the star’s large final explosion and collapse to a black hole.

“These explosions were only expected to be seen in the early Universe and should be extinct today,” said Dr. Andy Howell, of Las Cumbres Observatory and the University of California, Santa Barbara.

“This is like finding a dinosaur still alive today. If you found one, you would question whether it truly was a dinosaur.”

Indeed, the ‘Pulsational Pair Instability’ theory may not fully explain all the data obtained for this event.

For example, the energy released by the supernova is more than the theory predicts. This supernova may be something completely new.

The astronomers continue to monitor iPTF14hls, which remains bright three years after it was discovered.

_____

Iair Arcavi et al. 2017. Energetic eruptions leading to a peculiar hydrogen-rich explosion of a massive star. Nature 551: 210-213; doi: 10.1038/nature24030

Read More




Leave A Comment

More News

Breaking Science News |

All DiscoverMagazine.com

NYT > Science

Latest Headlines | Science

Science | Popular Science

Latest Science News --

Science - The Huffington

Christian Science Monitor |

Nature - Issue - nature.com

Scientific American Content:

Latest News from Science

Science | Smithsonian

Live Science

Science News - UPI.com

Astronomy News – Sky

Space.com

Disclaimer and Notice:WorldProNews.com is not the owner of these news or any information published on this site.