by Astronomers have spotted a star devouring a planet in a possible preview of Earth’s ultimate fate.
When a star runs out of fuel, it will swell to a million times its original size, gobbling up any matter — and planets — in its wake.
While scientists have observed hints of stars just before and shortly after consuming entire planets, they have never seen one in action until now.
In the new study, scientists from MIT, Harvard University, Caltech and elsewhere report that they have observed for the first time a star engulfing a planet.
The event appears to have taken place in our own galaxy, about 12,000 light-years away, near the eagle-like constellation Aquila.
Astronomers spotted an outburst of a star that became more than 100 times brighter in just 10 days before quickly fading away.
This incandescent flash was followed by a cooler, longer-lasting signal, according to research published in Nature.
Only one event — a star engulfing a nearby planet — could have produced this combination, the scientists suggest.
“We were seeing the final stage of swallowing,” said lead author Kishalay De, a postdoc at MIT’s Kavli Institute for Astrophysics and Space Research.
Experts suggest that Earth will meet a similar end to this planet, but not for another five billion years, when the sun is predicted to go out and burn up the inner planets of the solar system.
Dr De said: “We are seeing the future of the Earth.
“If some other civilization were watching us from 10,000 light-years away as the sun was engulfing the Earth, they would see the sun suddenly brighten as it ejects material, then form dust around it, before returning to what it was.”
The planet observed in the new research is estimated to have been a hot Jupiter-sized world that spiraled in, then was drawn into the dying star’s atmosphere and, finally, into its core.
The explosion was discovered in May 2020, but it took astronomers another year to piece together an explanation for what the explosion might be.
The initial signal appeared in a search for data taken from the Zwicky Transient Facility (ZTF), operated at Caltech’s Palomar Observatory in California.
The ZTF scans the sky for rapidly changing stars whose patterns may be the signature of supernovae, gamma-ray bursts and other stellar phenomena.
Dr De said: ‘One night I noticed a star that brightened by a factor of 100 over the course of a week, out of nowhere.
“It was unlike any stellar explosion I’ve seen in my life.”
He added: ‘For decades we’ve been able to see the before and after – before, when planets are still orbiting very close to their star, and after, when a planet has already been engulfed and the star is giant.
“What we were missing was catching the star in the act, where you have a planet suffering this fate in real time. That’s what makes this discovery so exciting.”
Astronomers observed the first direct evidence of a dying star expanding to engulf one of its planets using the power of the Gemini South Adaptive Optics Imager (GSAOI) on the Gemini South Telescope in Chile, one half of the Gemini International Observatory, operated by the National NOIRLab of the Scientific Foundation.
This research was supported, in part, by NASA, the US National Science Foundation and the Heising-Simons Foundation.
