Exploding star caught in the act

Exploding star caught in the act
By Paul Rincon
Science reporter, BBC News

Astronomers have been able to capture and record the first moments when a massive star blows itself apart.

After decades of searching, researchers have used the world’s top telescopes to observe the remarkable event.

Previously, scientists had only been able to study these “supernovas” several days after the event.

The results, published in the journal Nature, show that within two hours of the blast, a giant fireball scattered radioactive debris across space.

"We were in the right place, at the right time"
Alicia Soderberg, Princeton University

Exploding stars, or supernovas, are some of the most spectacular events in the Universe, producing the same amount of energy as trillions of nuclear bombs detonating simultaneously.

Their extreme brightness allows them to be seen in distant galaxies.

But observers cannot pick up this optical emission until several hours or days after the explosion, so a supernova’s first moments are shrouded in mystery.

Death of a star

The event in the constellation of Lynx was captured by pure chance.

Alicia Soderberg, from Princeton University in New Jersey, and her colleagues were using the Swift space telescope to survey the spiral galaxy NGC2770.

They saw an extremely luminous X-ray outburst in an area of sky that had shown nothing bright just two days earlier.

They attribute the outburst to the breaking out of the supernova shockwave, which ploughs its way through the star’s gaseous outer layers.

“We were in the right place, at the right time, with the right telescope,” Dr Soderberg explained.

The initial observations were followed up by some of the world’s major telescopes.

“We were able to observe the evolution of the explosion right from the start,” said co-author Edo Berger, from the Carnegie Observatories in California.

“This eventually confirmed that the big X-ray blast marked the birth of a supernova.”

The researchers say the blast occurred when a distant sun ran out of fuel and collapsed to form a hot relic called a neutron star.

Astronomers say that supernovas are part of the story of how we came to be, because these tremendous explosions created many of the heavy elements from which planets are made.

The authors say the event will help astronomers fill in gaps about the properties of massive stars, the birth of neutron stars and black holes, and the impact of supernovas on their environments.

Paul.Rincon-INTERNET@bbc.co.uk</a

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This article is from the BBC News website. © British Broadcasting Corporation

Source: news.bbc.co.uk

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