Star eats planet: Astronomers make unprecedented find in deep space

Astronomers have known what happens to planets like Mercury, Venus and Earth when their host stars are about to die, but they had never observed it happening in space, until now.

Using the Gemini South telescope(opens in a new tab) In Chile, scientists have seen the first evidence of an old, bloated star absorbing an exoplanet as it inflates during its final throes. The event was observed in a long, low-energy burst – the sign of a planet skimming the surface of a star.

In the past, astronomers have found evidence of stars that have consumed planets, sometimes performing a kind of post-mortem autopsy of what’s left of the dead star. But new research(opens in a new tab) published in the magazine Nature presents the first direct evidence of the star-eating-planet as it happened. The group hopes the event will provide other researchers with useful clues to discover other planet-consuming stars elsewhere in the universe.

“Our interpretation … provides evidence for a missing link in our understanding of the evolution and ultimate fate of planetary systems,” the study authors wrote.(opens in a new tab).

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During the event, about 12,000 light-years away from Earth in the direction of the constellation Aquila, the dying star, roughly the size of the sun, absorbed a planet up to ten times the mass of Jupiter , according to the study.

“Our interpretation … provides evidence for a missing link in our understanding of the evolution and ultimate fate of planetary systems.”

Unlike giant stars that explode in a supernova and collapse into a black hole, an average star like the sun suffers a more tortured end by slowly dying. A so-called “planetary nebula” – a confusing misnomer because stars, not planets, cause them – is a phenomenon made from the silent layers of an old star. Such spectacular clouds of gas and dust(opens in a new tab) occurs when a star withers as it loses nuclear fuel.

What remains of the star’s core cools. Then the light goes out.

Do stars eat planets?

“For decades, we’ve been able to see the before and the after,” said Kishalay De, an MIT researcher and lead author, in a university press release.(opens in a new tab). “Before, when the planets are still orbiting very close to their star, and then, when a planet has already been swallowed up, and the star is giant. What we needed was to catch the star in the act, where you have a planet in the making. that destiny in real time. That’s what makes this discovery really exciting.”

Scientists say they have finally captured a star in the act of swallowing a planet in the final stages of its life.
Credit: K. Miller / R. Hurt (Caltech / IPAC) illustration

Astronomers expect this to be the future of the sun in about 5 billion years.

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It would be impossible to watch a single star go through its entire life cycle for obvious reasons: That would take billions of years, said Paul Sutter, a professor at Stony Brook University and author of How to die in space, in an interview with Mashable last year. But experts have been able to predict such a grotesque end for a planet by studying many stars at different intervals and how they interact with their environment as they age.

“It’s like taking a snapshot of everyone on Earth at one moment. You can’t capture a person’s life, but you can see people being born, you can see people playing football in elementary school, and you can see people getting married . You can see people dying, getting sick,” said Sutter, who was not involved in the new study. “You can reconstruct a person’s life cycle by putting all these separate pieces together, so we have a big picture of how stars evolve and how they live.”

Will the sun eat the Earth?

Evidence suggests that as the sun eventually goes through this slow demise, Earth will likely face the same fate as the planet observed by the research team.

“We’re not exactly sure how big the sun is going to be — there’s a little bit of uncertainty in that it’s either going to completely circle the Earth or it’s just going to basically come to the edge of our orbit,” Sutter said previously. “It would incinerate the Earth anyway.”

Infographic about a star swallowing a planet.
Credits: Gemini International Observatory / NOIRLab / NSF / AURA / P. Marenfeld

New study confirms that when a Sun-like star nears the end of its life, it expands to become a red giant, 100 to 1,000 times its original size, eventually overtaking nearby planets . These events are believed to be rare, occurring only a few times each year across the galaxy.

The outburst caused by the star that engulfed the planet lasted about 100 days, according to the study.

“I think there is something quite remarkable about these results that speaks to the transience of our existence,” said Ryan Lau, an astronomer and co-author at NOIRLab, in a statement.(opens in a new tab). “After the billions of years that span the lifespan of our Solar System, our own final stages will likely conclude in a final flash lasting only a few months.”