The European Space Agency has released the world’s most exhaustive star catalog, pinpointing the positions of nearly 1.7 billion stars.
Today’s release, based on 22 months’ worth of data from ESA’s Gaia sky-mapping satellite, follows up on an initial version of the catalog that was released in 2016. This second release adds readings from the period between September 2015 and May 2016.
The Gaia mission’s second data release was presented at the ILA Berlin Air and Space Show in Germany. In addition to the positional data, the new catalog lists parallax and velocity readings for 1.3 billion stars — making it easy for astronomers to plot their distances and motions with respect to Earth.
“The observations collected by Gaia are redefining the foundations of astronomy,” Günther Hasinger, ESA’s director of science, said in a news release.
Astronomy fans agreed, and gushed over the treasure trove on Twitter:
Love this radial velocity map. Can anyone who isn't too busy #GaiaDay-ing explain why all those stars in the inner galaxy are going the wrong way? pic.twitter.com/uQIKw6ZWtx
— Natalie Wolchover (@nattyover) April 25, 2018
Basic reason is that the angular rotation speed of the Milky Way disk decreases with distance from the center and these velocities are wrt the Sun: stars inside the Sun's orbit overtake us, we overtake those outside, change-over occurs at 1/4 and 3/4 in this diagram #GaiaDR2
— Jo Bovy (@jobovy) April 25, 2018
THE CLUSTER CMD POPS OUT JUST LIKE THAT! Folks. This used to take YEARS of painstaking proper motion analysis. YEARS! And my blue stragglers are there!!! THIS IS SO COOL!!!✨ #GaiaDR2 pic.twitter.com/nT1OZ7KM2G
— Natalie Gosnell (@Nattie_G_) April 25, 2018
360º animated view of the sky in the northern hemisphere on 25 April 2018 – based on #GaiaDR2 data released today.
More about @ESAGaia second data release https://t.co/GJfRXcMUGmhttps://t.co/rL1almRB0q— ESA (@esa) April 25, 2018
The corkscrew pattern made by this star is Earth's orbital motion projected onto the sky, combined with that star's own independent motion through our galaxy. How cool is that? #GaiaDR2 pic.twitter.com/o7xpeMTqjy
— Corey S. Powell (@coreyspowell) April 25, 2018
Astrophysical parameters are part of the #GaiaDR2 Catalogue as well. A new extinction map based on dust just came out as well: https://t.co/sEqeXF3vqg #GaiaDR2 pic.twitter.com/FhFB7UpTtS
— ESA Gaia (@ESAGaia) April 25, 2018
Gaia was launched in 2013 and uses two telescopes to track stars and other celestial objects from the vicinity of a gravitational balance point known as Sun-Earth L2. To determine distances and motions, Gaia tracks apparent shifts in the position of objects against their cosmic background as the truck-sized spacecraft moves around the sun.
In addition to mapping stars, Gaia tracks asteroids in our solar system and quasars far beyond our galaxy. Today’s data release provides positional data on 14,000 asteroids and about half a million quasars. Future releases are expected to add to all those tallies.
The $900 million (€740 million) primary mapping mission is due to last until 2019.
Scientific papers describing the data contained in the release and their validation process will appear in a special issue of Astronomy & Astrophysics. A series of 360-degree videos and other virtual-reality visualization resources are available at http://sci.esa.int/gaia-vr.
