Estimating Gaia’s performance for O stars in the Outer Galactic Plane using Herschel data

K.L.J. Rygl, S. Molinari, T. Prusti, T. Antoja, D. Elia, J. de Bruijne (ESTEC-ESA, The Netherlands)

It is in the less dense Outer Galaxy where Gaia can contribute much to stellar studies of the Galactic Plane. Using Herschel column density maps of the Galactic Plane we estimate the extinction in the Outer Galaxy and derive the farthest accurate Gaia astrometry for O-stars. As O stars are by definition young (~Myr) objects their positions and kinematics can still be related to their formation site and history. Thus, the Gaia O star astrometry will be not only important for studies of high-mass star formation, but also an interesting complement to the radio maser astrometry of star-forming regions. We find that the Outer Galaxy extinction is such that Gaia astrometry will be able to transgress the Perseus arm.