From September 14, 2021 15:30 until September 14, 2021 16:30
Posted by Patricia Tissera
Stellar variability in the Gaia Era: the Gaia DR3 harvest
INAF - Osservatorio di Astrofisica e Scienza dello Spazio (OAS), Bologna
The last couple of decades have seen a true revolution in the field of stellar variability thanks to the increasing number of ground/space-based facilities and surveys that have been collecting multi-epoch photometry over large portions of the sky. A leading role in this revolution is played by Gaia, the ESA cornerstone mission that monitors the whole sky since July 2014, obtaining astrometric parameters (positions, parallaxes and proper motions) and multi-epoch photometry in three different pass-bands (Gaia G, G_BP and G_RP) of sources down to a limiting magnitude G = 21 mag. The spacecraft also simultaneously collects spectroscopy with the Radial Velocity Spectrometer (RVS) of the sources brighter that V ? 16 mag. In the first half of 2022, the second instalment of Gaia third data release (DR3), will publish time series multi-band photometry and parameters for about 14 million sources and more that 20 different variability types. Epoch RVS radial velocities will be also released for about 2000 RR Lyrae stars and Cepheids. We discuss some of the Gaia DR3 variability results, focussing more specifically on the RR Lyrae stars and Cepheids, in light of the impact these variable stars have on the definition of the cosmic distance ladder and the study of resolved stellar populations in and beyond the Milky Way. Future perspectives opened by upcoming new facilities such as the Vera Rubin Observatory and spectrographs such as WEAVE, MOONS and 4MOST will also be briefly considered.