Gaia Data Release 2: Variable stars in the colour-absolute magnitude diagram

Understand

The ESA Gaia mission provides a unique time-domain survey for more than 1.6 billion sources with G ~ 21 mag.

• We showcase stellar variability across the Galactic colour-absolute magnitude diagram (CaMD), focusing on pulsating, eruptive, and cataclysmic variables, as well as on stars exhibiting variability due to rotation and eclipses.
• We illustrate the locations of variable star classes, variable object fractions, and typical variability amplitudes throughout the CaMD and illustrate how variability-related changes in colour and brightness induce `motions' using 22 months worth of calibrated photometric, spectro-photometric, and astrometric Gaia data of stars with significant parallax.
• To ensure a large variety of variable star classes to populate the CaMD, we crossmatch Gaia sources with known variable stars.