Cosmic burp may end in star’s suicide

A vampire star that burped violently after biting off more than it could chew looks set to produce the biggest explosion in the galaxy. The stellar cannibal flared in brightness and threw off a shell of gas after devouring a large chunk of a helpless companion.

Astronomers have been monitoring the case of cosmic indigestion in a twin-star system called V445 Pup in a southern constellation called Puppis – the Ship’s Stern.

They say the vampire star appears to be a ticking time bomb on the verge of blowing itself to bits in a spectacular stellar suicide.

V445 Pup lies 250,000 light-years away from Earth. Its earlier outburst, first spotted in November 2000, is the subject of a report this week in the Astrophysical Journal.

Space scientists have produced a time-lapse movie of the shell of gas being ejected at 15,000mph, using Europe’s powerful Very Large Telescope in Chile. Producing the pictures was as challenging as observing detail on a pound or euro coin 25 miles away.

They say the double star – a white dwarf circling a red giant – appears to be a prime candidate for a Type Ia supernova which will explode to become as bright as all the other stars in the Milky Way put together.

A clue to V445 Pup’s fate is that it is the first flaring star ever observed to show no sign of hydrogen, despite that being the most common element in the universe.

Astronomer Danny Steeghs, of the University of Warwick in the UK, said: “This is critical, as we know that Type Ia supernovae lack hydrogen. The companion star in V445 Pup fits this nicely by also lacking hydrogen, instead dumping mainly helium gas onto the white dwarf.”

Colleague Patrick Woudt, of the University of Cape Town, South Africa, said: “One of the major problems in modern astrophysics is that we still do not know exactly what kinds of stellar system explode as a Type Ia supernova.

“As these supernovae play a crucial role in showing that the universe’s expansion is currently accelerating, pushed by a mysterious dark energy, it is rather embarrassing.”

He added: “Whether V445 Pup will eventually explode as a supernova, or if the current nova outburst has pre-empted that pathway by ejecting too much matter back into space is still unclear. But we have here a pretty good suspect for a future Type Ia supernova!”

Another, much closer, star that may one day become a supernova is Betelgeuse in Orion. Other supernova factories are known. Some dramatic clouds of gas reveal the sites of previous such explosions.

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