Did interstellar asteroid Oumuamua pass near other stars?
A recently released paper on arXiv (Bailer-Jones et al., AJ) has made use of the recently released GAIA-DR2 data set, and specifically the 7 million stars that have full 6D information, to try and find plausible home stars for 'Oumuamua. They found 4 potential systems of which the closest encounter was at 0.6 parsecs with the M2.5 dwarf HIP 3757 at a relative velocity of 24.7 km/s, 1 million years ago.  However all of the encounter stars have quite high encounter velocities.  A giant planet or a binary system could provide the needed velocity but none of the 4 systems are known to be binaries or to harbor planets. However 7 million stars with full information is still a pretty small fraction of the total, a situation which will improve with later data releases.