J-PLUS: characterization of high-velocity stars in the second data release

High-velocity stars in the Milky Way are related to extreme astrophysical phenomena. In this work, we characterize 28 stars with Galactocentric velocities higher than 400 $\mathrm{km\, s^{-1}}$ observed in the Javalambre Photometric Local Universe Survey Data Release 2 (J-PLUS DR2) survey. We combine J-PLUS photometry with astrometric data from the Gaia DR3 catalogue to analyse the kinematics, dynamics, and fundamental stellar parameters of these stars. Our results indicate that most of the 28 stars have typical behaviour and properties of halo stars, and some of them could be related to the disk population. Some of the halo stars may belong to known structures that originated from mergers of other systems with the Milky Way.