Gaia and science of Solar System Objects
Séminaire IPAG de Daniel Hestroffer (IMCCE), jeudi 27 septembre 2018 à 11h00, salle Manuel Forestini
The Gaia ESA space mission provided its first harvest in 2016, with the DR1 catalogue release ; yielding improved astrometry from classical ground-based observations of Solar System Objects (SSOs). Albeit of high interest, the DR1 data release has been largely surpassed by the DR2 release. Indeed, the Gaia DR2 is a major step in the Gaia mission by providing the very first full stellar catalogue, that includes all astrometric parameters (positions, parallaxes, and proper motions) at unprecedented precision, and this for more than 1 billion stars. All these positions are given in an absolute reference frame - to become the optical ICRF. Moreover, Gaia DR2 did provide for the first time astrometry of SSOs, more precisely, epoch positions of about 14,000 asteroids distributed from inner to outer regions of the Solar System, from the direct observations by the satellite down to magnitude V≈20.7.
I will present the generalities of the Gaia surveying mission, and current status. I will then discuss the improvement brought by Gaia over its 5 years and more of mission—starting with DR1—for the science of asteroids and other SSOs ; and focusing especially on the astrometry and dynamics of asteroids. After reminding generalities on SSO observations by Gaia - and some of their peculiarities, we present some of the advances obtained from the use of the Gaia catalogues for the calibration and reduction of SSO astrometry. We also illustrate the ground-based activity coordinated by the Gaia-FUN-SSO network for follow-up observations of newly discovered objects, particularly Near Earth Objects. We will also present advances in observations of stellar occultations, and studies of asteroids’ dynamic.