mercredi 21 février 2018

An amateur astronomer hits the jackpot at the "Cosmic Lottery"












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February 21, 2018

An Argentine amateur astronomer was able to detect the violent explosion of a star at the end of life, a rare phenomenon and of course unpredictable.

The supernova has been detected in the galaxy NGC 613. Photo Credit: Víctor Buso

One chance in 100 million, the dream of any astronomer: an Argentine amateur has flushed a supernova, the violent explosion of a star at the end of life, reveals a study published Wednesday.

"Professional astronomers have long been looking for such an event," says Alex Filippenko of the American University of Berkeley, co-author of the study. "It's like winning the cosmic lottery," he said in a statement from the University of California.

"The measures of Víctor Buso (amateur astronomer, ed) constitute an unprecedented set of data," said AFP Federico Garcia of the French Atomic Energy Commission, also co-author of the study. It's "exceptional", adds his colleague Alex Filippenko.

On September 20, 2016, Victor Buso from Argentina, who is passionate about the stars, decides to test a new camera on his telescope.

From his home town of Rosario, north of Buenos Aires, he chose, for his first shots, the galaxy NGC 613, located about 80 million light-years from Earth, in the constellation of the Sculptor. Coup de chance: A massive star has just spent its last hours in a cataclysmic explosion known as the supernova.

Galaxy NGC613. Image Credit: Caelum Observatory

The phenomena that accompany the death of a star are very violent because, according to the theory, the matter composing the star is ejected at speeds of several thousand kilometers per second. Due to the incredible amount of energy released, the event shines a lot and can be seen from the Earth.

But the phenomenon is rare and above all unpredictable. Astronomers usually detect it after several days and never at its beginning, as was the chance to do it Victor Buso.

An explosive shock wave

The enlightened amateur gives the alert via the American association of the observers of variable stars (AVVSO), triggering a reaction in chain: a battery of astronomers and physicists point their instruments on the phenomenon. Some will watch the aftermath of the explosion for more than two months.

According to the study published in the British journal Nature, the new data collected allow to better understand the physical structure of the star just before its disappearance and the nature of the explosion.

The team was able to estimate that the initial mass of the star was about 20 times the mass of the Sun.


Animation above: Supernova in NGC 613. Amateur Astronomer Captures Supernova's First Light in NGC 613. Images Credit:Víctor Buso/Animation Credit: Sky & Telescope.

The researchers were also able to observe a spectacular increase in the brightness of the supernova, "in less than half an hour, the object had multiplied its brightness by 3", according to a statement from the French University Paris Diderot.

This could correspond to the emergence of a luminous wave, an explosive shock wave on the surface of the star, already predicted by models but never observed. "The blast wave of the explosion emerges from the stellar surface, having penetrated the supersonic interior of the star. At that moment, a huge quantified light is violently released in a flash of light, "the statement said.

Victor Buso had "only one chance in 10 million or even 100 million" to see this show, says Melina Bersten of the Institute of Astrophysics of La Plata in Argentina, who also participated in the study.

Wikipedia: NGC613: https://en.wikipedia.org/wiki/NGC_613

Animation (mentioned), Images (mentioned), Text, Credits: AFP/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

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