European satellite releases info on more than 1 billion stars

The European Space Agency (ESA) has released the first data from its Gaia satellite, detailing the position and brightness of 1.14 billion stars in the Milky Way galaxy, as well as the distances and motions for more than 2 million.

This is only a sampling of data from the first 14 months of a larger project to create a 3-D map of 1 billion stars that will be completed in the next year and promises to give scientists a much greater understanding of our galaxy. 

"Gaia is at the forefront of astrometry, charting the sky at precisions that have never been achieved before," said Alvaro Giménez, ESA's Director of Science. "Today's release gives us a first impression of the extraordinary data that await us and that will revolutionize our understanding of how stars are distributed and move across ourgalaxy."

The project owes its success thus far to the collaborative effort of 450 scientists and engineers involved in the Gaia Data Processing and Analysis Consortium and the Gaia telescope's incredibly sophisticated technology. Gaia consists of two tools, a 1 billion pixel camera detector and ultra-stable and super-sensitive optical equipment that allows Gaia to measure the coordinates of a star down to an error of just seven micro-arcseconds.

When the ESA launched Gaia in July 2014, its goal was to expand on the work of Hipparcos, the previous star catalogue of the nearby Milky Way. Hipparcos mapped the position, distance from Earth, and brightness of 100,000 stars, and Gaia has already produced 20 times as much data with a greater degree of precision.

The ESA has opened up a web portal for the public to explore the massive volume of data – and possibly make new celestial discoveries.

"With Hipparcos, we could only analyse the 3-D structure and dynamics of stars in the Hyades, the nearest open cluster to the Sun, and measure distances for about 80 clusters up to 1,600 light-years from us," said Antonella Vallenari from the Istituto Nazionale di Astrofisica (INAF) and the Astronomical Observatory of Padua, Italy. "But with Gaia's first data, it is now possible to measure the distances and motions of stars in about 400 clusters up to 4,800 light-years away."

Many of Gaia's measurements includes the radial velocity of stars – how stars move toward or away from the satellite. A composite look at this data will give scientists insight into how the galaxy came to look the way it does today and how it may look in the future.

Additionally, it contains instruments that measure composition and temperature, which scientists can use to calculate the age of stars and thus generate a timeline, as well as a map, of the Milky Way.

"The beautiful map we are publishing today shows the density of stars measured by Gaia across the entire sky, and confirms that it collected superb data during its first year of operations," said Timo Prusti, Gaia project scientist at ESA. He added that although the data is still tentative, the team wanted to release it for scientific use as soon as possible.

As immense as it is, Gaia's map will only capture 1 percent of the total stars that make up the Milky Way.

Material from the Associated Press contributed to this report.