Stellar variability in Gaia DR3

The position of an object in the dispersion-dispersion planes can be used to constrain its variability type, a direct application of these results.We use information from the MW, LMC, and SMC color-absolute magnitude diagrams (CAMDs) to discuss variability across the Hertzsprung-Russell diagram. White dwarfs and B-type subdwarfs are more variable than main sequence (MS) or red clump (RC) stars, with a flat distribution in S_G_ up to 10mmag and with variability decreasing for the former with age.

The MS region in the Gaia CAMD includes a mixture of populations from the MS itself and from other evolutionary phases. Its S_G_ distribution peaks at low values (~1-2mmag) but it has a large tail dominated by eclipsing binaries, RR Lyr stars, and young stellar objects. RC stars are characterized by little variability, with their sG distribution peaking at 1 mmag or less.

The stars in the pre-main-sequence (PMS) region are highly variable, with a power law distribution in sG with slope 2.75 and a cuto for values lower than 7mmag. The luminous red stars region of the Gaia CAMD has the highest variability, with its extreme dominated by AGB stars and with a power law in sG with slope 2.2 that extends from there to a cuto of 7mmag. We show that our method can be used to search for LMC Cepheids.

We analyze four stellar clusters with O stars (Villafranca O-016, O-021, O-024, and O-026) and detect a strong difference in S_G_ between stars that are already in the MS and those that are still in the PMS.