Study Of "Twin" Stars Finds Evidence Of Planetary Ingestion

An examination of 91 pairs of stars with matching sizes and chemical compositions showed that a surprising number exhibited signs of having ingested a planet, scientists said on Wednesday.

The planetary system that includes Earth and its sibling planets orbiting the sun has been remarkably stable during its roughly 4.5 billion years of existence. But not all planetary systems are so lucky, as shown in a new study involving "twin" stars.

An examination of 91 pairs of stars with matching sizes and chemical compositions showed that a surprising number exhibited signs of having ingested a planet, scientists said on Wednesday, likely after the planet was sent hurtling out of a stable orbit for any number of reasons.

The study looked at pairs of stars that formed within the same interstellar cloud of gas and dust - so-called co-natal stars - giving them the same chemical makeup, and were of roughly equal mass and age. These are the "twins." While the pairs are moving together in the same direction within our Milky Way galaxy, they are not binary systems of two stars gravitationally bound to each other.