Gaia’s Stellar Family Portrait, an interactive visualisation to explore the data from the second release of ESA's Gaia mission, which has been charting the sky to create the most precise map ever made of stars in our Milky Way galaxy. The new visualisation focusses on the Hertzsprung-Russell diagram, a fundamental tool for astronomers to study populations of stars and their evolution.
The Hertzsprung-Russell diagram can be imagined as a stellar family portrait: stars are plotted according to their colour (on the horizontal axis) and brightness (on the vertical axis) and are grouped in different regions of the diagram depending mainly on their masses, chemical composition, ages, and stages in the stellar life cycle. Information about stellar distances is fundamental to calculate the true brightness, or absolute magnitude, of stars.
Dive into the Gaia data at http://sci.esa.int/gaia-stellar-family-portrait/