Orbits and Chemical Abundances in the Milky Way with Gaia DR2 (Johanna Coronado; MPIA)

From January 29, 2019 13:15 until January 29, 2019 13:45

At Instituto de Astrofísica, Pontificia Universidad Católica, Vicuña Mackenna 4860, Santiago, Chile

Categories: Seminarios

Present and recent sky surveys have advanced in the effort of studying the Milky Way, making volume complete samples in both position and velocity space. In this work, the aim is to explore to which extent stars with very similar abundances are on similar or different orbits, which could give us hints on the effects of radial migration in the disc of the Milky Way. In order to do this, we need to have sizeable samples with good abundances (from a spectroscopic survey such as APOGEE or LAMOST), good distances (parallax or photometric) and proper motions (from Gaia). Here we present our probabilistic approach to model spectroscopic information that we applied to obtain improved spectrophotometric distances (with errors less then 6%) for main sequence stars in the LAMOST DR5 x Gaia crossmatch. We explicitly account for the individual parallax uncertainties in the model building and fully incorporate the binarity of main sequence stars. For the fainter and more distant stars of most current spectroscopic surveys, an approach such as the one presented in this work delivers better distances than Gaia Data Release 2. With these improved distances we then explore the orbital actions and the chemical information from all the main sequence stars in the LAMOST sample.