It’s a moment of conception on an interstellar scale. Australian astronomers have watched the death — and rebirth — of a distant solar system. Now they’re watching its embryonic nebula form.

Professor Lisa Harvey-Smith of the CSIRO has told the annual meeting of the Astronomical Society of Australia hosted at Swinburne University this week that the opportunity to observe the climactic phase in the life cycle of a star was extraordinary.

The cycle of a star’s life begins as it ends.

From a supergiant’s last ragged breaths comes a planetary nebula — a cloud of gas made from the very stuff that forms new stars and worlds.

“We decided to watch one of these ‘born again’ episodes as it happened,” Harvey-Smith told the gathering.

She and other astronomers like her have been watching this reproductive process “live” for the past 30 years.

“A lot of astronomy takes places over millions of years, so it’s rare, but extremely interesting when you see things change over the course of a human lifetime,” commented Swinburne University astrophysicist and the Royal Institution of Australia’s lead scientist, Alan Duffy.

“This is called a ‘helium flash,’ as helium in the star ignites and burns brightly before fading again,” Harvey-Smith says. “It is extremely rare to catch a star going through one of these events, so we grabbed the opportunity and used our giant radio telescopes to follow its evolution.”

The resulting study has been published in the latest edition of the Monthly Notices of the Royal Astronomical Society.

The object of the astronomers’ attention was initially a somewhat sickly supergiant star, SAO 244567.

It was identified as a hot supergiant back in 1971. A check-up in 1988 indicated that it was under some stress.

By 1991, spectral analysis proved something big was about to happen.

The star’s fusion process had destabilized. Its outer layers were heating rapidly. The resulting helium-fusion flash would cause the gas envelopes of the star to be blown out into space.

The peak of just such an event was recorded in 2002.

By 2015 the star had cooled once again, though it had left behind an immense glowing cloud of dust and gas. It now seems to be holding steady.

“The born-again event is over,” Harvey-Smith says. “The nebula is now cooling and expanding”.

What is left behind is an embryonic planetary nebula.

It’s been dubbed the Stingray Nebula.

And an analysis of data gathered from the Australia Telescope Compact Array data is casting new light on what’s been going on.

The first optical and radio images of what’s going on appear to reveal the origins of the swirling clouds of gas that may eventually form new stars and planets.

“It is remarkable because it is the youngest known planetary nebula and we can watch it actively evolving,” Harvey-Smith says.

“In this work, we made the first ever image of the Stingray nebula in radio waves, which we photographed using the CSIRO’s Australia Telescope Compact Array near Narrabri in NSW.

“One of the reasons we wanted to study this object is to figure out why this planetary nebula is not spherical but has a complex shape.”

There’s a bright inner ring around the star. Both show what Harvey-Smith describes as “ears,” possibly linked to the behavior of the dying star’s surface.

“The radio images and spectrum lead us to believe it may be starting to shoot a fast ‘outflow’ of gas from the star,” she says. “If so, this will likely have an impact on the way the nebula’s shape is evolving.”

This could be related to the appearance of “non-thermal” emissions — charged particles emitted by the star.

“These beautiful radio observations are only possible thanks to the exquisite sensitivity of Australian radio telescopes,” Duffy says.