Milky Way Census Shows Stars Take Varied Paths

Milky Way Census Shows Stars Take Varied Paths

The Gaia satellite is making the most detailed and complete map of the stars in our galaxy

Credit: Nadieh Bremer

After launching to space in 2013, the European Space Agency’s Gaia telescope has been spinning in full circles every six hours, mapping all the stars it can see in every direction. Scientists have released a new catalog that includes the latest data from the mission, including measurements of the chemical compositions, temperatures and masses of nearly two billion stars in our Milky Way. These data show typical star trends: Large stars tend to be young and hot. The older massive stars won’t be around for very long so they will be gone by now. We find smaller stars with lower masses at all ages. They are cooler and more reddish.

Gaia’s observations allow astronomers to piece together the history of our galaxy and see how it compares to other galaxies. Timo Prusti is Gaia’s project scientists. “We are inside the Milky Way.” “It’s like a forest. You see many trees, but you don’t know what the forest looks because you are inside. Gaia is a tool that measures all trees to determine what it looks like

85,000 stars are grouped by spectral type, age, solar luminosity, temperature, solar mass and solar radius.
Credit: Nadieh Bremer (graphic); “Gaia Data Release 3: A Golden Sample of Astrophysical Parameters,” by Gaia Collaboration, arXiv, 2022 (data)

This article was originally published with the title “Milky Way Census” in Scientific American 327, 6, 80 (December 2022)

doi: 10. 1038/scientificamerican1222-80



    Clara Moskowitzis Scientific American‘s senior editor covering space and physics. She holds a bachelor’s degree from Wesleyan University in astronomy, and a master’s degree from the University of California at Santa Cruz in science journalism. Follow Moskowitz on Twitter @ClaraMoskowitz Credit: Nick Higgins

    Read More