Milky Way gobbles up a wandering planet
IT is tempting to describe it as a wandering star but scientists would say it is in fact a planet.
Either way, there can be no arguing about its roving nature.
The first planet formed in another galaxy has been discovered.
The Jupiter-sized world orbits a star that was drawn into our own galaxy, the Milky Way, six to nine billion years ago.
It inhabits the Helmi stream, a group of stars that originally belonged to a neighbouring dwarf galaxy. Gravity eventually caused the dwarf to be devoured by the Milky Way in an act of "galactic cannibalism".
Dr Rainer Klement, from the Max Planck Institute for Astronomy in Heidelberg, Germany, said: "This discovery is very exciting.
" For the first time, astronomers have detected a planetary system in a stellar stream of extra-galactic origin.
"Because of the great distances involved, there are no confirmed detections of planets in other galaxies. But this cosmic merger has brought an extra-galactic planet within our reach."
The parent star, known as HIP 13044, lies around 2,000 light years from Earth in the southern constellation of Fornax (the Furnace).
Astronomers found the planet from the way the tug of its gravity caused the star to "wobble".
It is one of the few known to have survived the massive 'red giant' expansion of an ageing host star.
Lead astronomer Dr Johnny Setiawan, also from the Max Planck Institute, said: "The discovery is part of a study where we are systematically searching for exoplanets that orbit stars nearing the end of their lives.
"This discovery is particularly intriguing when we consider the future of our own planetary system, as the sun is also expected to become a red giant in about five billion years."