Planets normally orbit stars – but now astronomers have found more than 70 of them, that roam freely through the galaxy like nomads. Presumably there are billions of them in the Milky Way.
Without their host star to illuminate them, these planets are difficult to detect. Only in the first ten million years after their formation are planets of Jupiter’s mass and up to 13 times its mass still hot enough to glow. Therefore, they can be located with the help of large telescopes.
The team of Núria Miret-Roig from Laboratoire d’Astrophysique in Bordeaux (France) found a huge group of these loners in a star-forming region in the constellations Scorpius and Ophiochus. The scientists evaluated more than 80,000 images taken over a 20-year period.
There are several theories about the origin of such vagabonding exoplanets. Based on the statistical analysis of the found objects, the researchers estimate that two mechanisms are most probable: either a gravitational interaction within the host star system, which led to a catapulting out of the loner. Or the collapse of a gas cloud that was too small to lead to the formation of a star. But astronomers do not rule out other mechanisms either.
Future observational data will hopefully soon provide new insights.
Read more about it here.