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It's a design moment on an interstellar scale. Australian astronomers have observed the death – and rebirth – of a distant solar system. Now they look at its embryonic nebula shape.
Professor Lisa Harvey-Smith of CSIRO said at the annual meeting of the Astronomical Society of Australia held at the University of Swinburne this week that the opportunity to observe the development phase The life cycle of a star was extraordinary.
The cycle of life of a star begins at the end.
According to the last irregular breaths of a supergante, a planetary nebula – a cloud of gas made from what forms new stars and new worlds.
"We decided to watch one of those" born again "episodes," said Harvey-Smith at the rally.
She and other astronomers as she watched this "live" reproduction process for the last 30 years.
"A lot of astronomy takes place over millions of years, so it's rare, but extremely interesting when you see things change over a human life," commented L & # 39; 39, University of Swinburne Astrophysicist and Alan Duffy, Principal Investigator, Royal Institution of Australia.
"This is called a" helium flash "because helium in the star ignites and burns brightly before disappearing again," says Harvey-Smith. "It is extremely rare to catch a star experiencing one of these events, so we seized the opportunity and used our giant radio telescopes to track its evolution."
The resulting study was published in the latest edition of the monthly notices from the Royal Astronomical Society.
The object of attention of astronomers was initially a somewhat sickly supergiant star, SAO 244567.
He was identified as a hot supergiant in 1971. A record of 1988 indicated that he was under some stress.
In 1991, spectral badysis proved that something big was about to happen.
The star merging process had been destabilized. His outer layers were heating up quickly. The resulting helium fusion flash would cause the star gas envelopes to be blown into space.
The peak of such an event was recorded in 2002.
By 2015, the star had cooled again, but it had left behind a huge cloud of dust and gas. He now seems to be maintaining himself.
"The event just born is over," says Harvey-Smith. "The nebula cools and expands".
What remains is an embryonic planetary nebula.
He was nicknamed the Stingray Nebula.
And an badysis of the data collected from the data of the Australia Telescope Compact Array sheds new light on what is happening.
The first optical and radiophonic images of what is happening seem to reveal the origin of the swirling clouds of gas that could eventually form new stars and planets.
"It's remarkable because it's the youngest known planetary nebula and we can see it evolve actively," Harvey-Smith explains.
"In this work, we made the first image of the Stingray Nebula in radio waves, which we photographed using the compact Australian telescope from CSIRO near Narrabri in New South Wales.
"One of the reasons we wanted to study this object is to understand why this planetary nebula is not spherical but has a complex shape."
There is a bright inner ring around the star. Both show what Harvey-Smith describes as "ears," possibly related to the behavior of the surface of the dying star.
"The radio images and the spectrum lead us to believe that he may be triggering a quick" exit "of star gas, she says. "If that's the case, it will probably have an impact on how the shape of the nebula evolves."
This could be related to the appearance of "non-thermal" particles loaded with emissions emitted by the star.
"These beautiful radio observations are only possible thanks to the exquisite sensitivity of Australian radio telescopes," says Duffy.
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