Scientists and astronomers around the globe were aflutter last year when an interstellar object called Oumuamua was discovered. The argument over the object spanned from if it was an asteroid or comet to what star system the object originated from. The ESA has been using data gleaned from the Gaia spacecraft to try and determine what star systems Oumuamua could have possibly originated from.
Gaia has identified four different stars as potential origins for the object. Initially, scientists called Oumuamua an asteroid and it was later found to be a comet. The comet revelation was made after it was discovered that Oumuamua wasn’t slowing the way it was expected with variations recorded in its trajectory. These variations were caused by gasses coming out of its surface making it more comet-like.
To figure out where the object hailed from scientists had to look at the trajectory of the comet and what stars might have crossed paths with the object in the last few million years. By studying the Gaia data, the scientists identified four possible stars with orbits that had come within a couple lightyears of Oumuamua in the near past that had relative velocities low enough to be compatible with likely ejection mechanisms.
All four of these possible home stars are dwarf stars with masses smaller than our Sun and had an encounter with the comet between one and seven million years ago. None of these stars are known to have planets or to be part of a binary system. Scientists say that having a binary star or large planet is the most preferred mechanism to have ejected Oumuamua into interstellar space.
Scientists studying the origins are looking forward to future Gaia data with a larger sample of radial velocities for stars that will allow the team to reconstruct and investigate trajectories or more stars. There are two Gaia data dumps expected in the 2020s. The scientists are clear that it is too early in the study to pinpoint Oumuamua’s origin.