SCIENCE
08/22/2012 11:35 am ET Updated Aug 22, 2012

Star Destroys Planet: Red Giant Caught Devouring Its Own Satellite

James Gitlin / STScI AVL

Astronomers have seen evidence that a planet has been "devoured by its own star," the BBC reports.

A group of scientists reported in the Astrophysical Journal Letters that they observed the aging star -- a red giant named BD+48 740 -- as it gobbled up its planet.

The astronomers added the encounter has provided some insight into the possible fate in store for Earth, which could -- in billions of years -- be engulfed by the sun.

“A similar fate may await the inner planets in our solar system, when the sun becomes a red giant and expands all the way out to Earth’s orbit some 5 billion years from now,” Alexander Wolszczan, professor of astronomy and astrophysics at Penn State University, said.

According to the Los Angeles Times, such events are not actually uncommon. Red giants are elderly stars that expand in size as temperatures near their cores rise -- a process which can cause nearby planets to be destroyed.

However, the newspaper notes these encounters usually "happen relatively quickly on a cosmological time scale and it is considered unlikely for one to be observed directly."

The team of scientists, headed by Wolszczan, used the Hobby-Eberly Telescope at the McDonald Observatory in Texas to study BD+48 740.

The astronomers said they found evidence of the planet's destruction in both the star's peculiar chemical composition, as well as the unusual elliptical orbit of its surviving planet.

“Our detailed spectroscopic analysis reveals that this red-giant star, BD+48 740, contains an abnormally high amount of lithium, a rare element created primarily during the Big Bang 14 billion years ago,” team member Monika Adamow said, according to Red Orbit.

Lithium is easily destroyed in stars, which is why the researchers found its abundance in the older star so unusual, BBC notes.

“In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet that spiraled into the star and heated it up while the star was digesting it,” Adamow explained.

The astronomers also cite the highly eccentric and extended orbit of another planet around the red giant as evidence of the phenomena.

"Such orbits are uncommon in planetary systems around evolved stars and, in fact, the BD+48 740 planet's orbit is the most elliptical one detected so far," said co-author Andrez Miedzielski of Poland's Nicolaus Copernicus University, according to the Los Angeles Times.

The astronomers suspect that the energy released when the missing planet was consumed by the star boosted the surviving planet into its unusual orbit.

In April, Caleb Scharf, the director of Columbia University's Astrobiology Center, discussed the complex relationship between stars and planets.

"Stars and planets have what might be the most dysfunctional relationship in astrophysics,"Scharf wrote in a blog post for the Scientific American.

"In particularly close configurations a planet can raise tides on the star itself, and one consequence of that is the potential for the planet to spiral inwards over millions to tens of millions of years and end up being shredded and engulfed by the star," he continued. "It appears to be all love and hate between planets and their stellar parents."

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