Report: Star swallowed its own planet
(CNN) -- Using a ground-based telescope to peer into a distant point of light, scientists have come up with a startling conclusion -- the star ingested one or more of its own planets.
The surprise discovery, the first of its kind, should hasten the search for other such voracious stars, boosting the understanding of planetary evolution, the European researchers said.
Located in the constellation Hydra, the star is slightly hotter and larger than our sun and was recently discovered to possess a pair of giant planets.
Like most of the dozens of planets found around other stars, these two gas giants have bizarre orbits, in this case rather elongated ones unusually close to the central star. Such planets are unlike any in our solar system and confound traditional theories of planetary formation.
Other explanations that account for the eccentric orbits also predict that some planets could plummet into their host stars, a hypothesis that the new observation seems to confirm, the scientists said.
Using the European Southern Observatory telescope in Atacama, Chile, the astronomers detected the presence of a rare variety of lithium in the star. The fragile metal would have been destroyed in the early, explosive evolutionary stages of this particular kind of star, which like our own is rich in heavy metals.
The best explanation that can account for the lithium is that the star ingested it much later, the Spanish and Swiss research team concluded.
"The simplest and most convincing way to explain this observation is that one or more planets, or at least planetary material, have fallen into the star, sometime after it passed through its early evolutionary stage," said astronomer Nuno Santos in a statement.
The star, known as HD82943, could have swallowed either a gas giant twice the mass of Jupiter or a small rocky one three times the mass of Earth, the astronomers estimated in their report, published in the May 10 issue of the journal Nature.
Scientists have discovered more than 60 planetary systems beyond our own in recent years, using powerful telescopes to measure the wobble brought about by orbiting planets on their host stars.
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