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An unlikely planet

A painting of an exoplanet in a violent environment of an evolved star.
[JSW Art 2007]

Ever wonder what other planets are lurking beyond our galaxy? Well, a new planet has been discovered near a star of extragalactic origin, implying that it comes from outside the Milky Way, reports a new study.

The finding may question our current understanding of planet formation and survival, since it is the first time astronomers have found a planet around an extremely metal-poor and very old star.

This research appears in the 18 November issue of the journal Science Express.

So far, very few planets have been detected around metal-poor stars (stars that contain very little elements other than hydrogen and helium) or very old stars.

Now, Johny Setiawan and colleagues at the Max Planck Institute for Astronomy in Germany have found a giant planet around a metal-poor star that has gone past the red giant phase of stellar evolution, when stars like the Sun expand up to many times their original size.

This newly discovered planet is at odds with expectations because it typically would have been swallowed up by its host star as it expanded.

Furthermore, the planet likely originated outside of our galaxy because its host star belongs to a group of stars that formed in a satellite galaxy of the Milky Way that was gravitationally disrupted several billion years ago.