New estimate of wandering Jupiter-mass worlds better matches ideas of how planets become orphans
J. Skowron/Warsaw Univ. Observatory
Big, rogue planets — ones without parent stars — are rare.
A new census of free-floating Jupiter-mass planets determined that these worlds are a tenth as common as previous estimates suggested. The results appear online July 24 in Nature.
Planets can go rogue in two ways: They can get kicked out of their parent planetary systems or form when a ball of gas and dust collapses (SN: 4/4/15, p. 22).
In the new study, Przemek Mróz of the Astronomical Observatory of the University of Warsaw and colleagues estimated the number of large, rogue planets in our galaxy using a technique called microlensing. When an object with a mass of a planet passes in front of a distant, background star, the gravity of the planet acts as a gravitational magnifying glass. It distorts and focuses the light,