April 25 (UPI) -- As promised, Gaia made its second data release available to the public on Wednesday, offering new details on some 1.38 billion stars.
The European Space Agency's Gaia observatory is roughly half-way to completing its "book of the heavens." Already, the mission has assembled the most comprehensive and precise map of the Milky Way, with data on a total of 1.7 billion stars.
Wednesday's data release comprised observations collected between July 2014 and May 2016 and builds on the first data release, shared in 2016.
"The second Gaia data release represents a huge leap forward with respect to ESA's Hipparcos satellite, Gaia's predecessor and the first space mission for astrometry, which surveyed some 118 000 stars almost thirty years ago," Anthony Brown, an astronomer at Leiden University in the Netherlands, said in a news release.
Launched in 2013, Gaia is working its way toward compiling the largest and most precise 3D space catalog in history. When Gaia's mission is complete, the space observatory will have surveyed a record 1 percent of the universe's 100 billion stars.
Gaia photographs its targets multiple times, and with each exposure the observatory accumulates information about each star's positioning and brightness. Because Gaia surveys stars multiple times, it can plot each star's real movement across the sky -- each star's orbital path through the universe.
Included in the new release are the radial velocities of 7.2 million stars and surface temperature estimates for 161 million stars. The data drop also includes radius and luminosity measurements for 76 million stars.
Though a wealth of surprising discoveries are expected as scientists begin to analyze the new data, researchers are already using the updated catalogue to identify different populations of stars, differentiating stellar groups by position, age and type.
Gaia's data promises to usher in a new era of research in the field of galactic archaeology, the study of the history and evolution of galaxy through analysis of the relationships between different groups of stars.
"Gaia is astronomy at its finest," said Fred Jansen, Gaia mission manager at ESA. "Scientists will be busy with this data for many years, and we are ready to be surprised by the avalanche of discoveries that will unlock the secrets of our Galaxy."