European satellite maps 1.7 billion stars (less than 1%)
The Gaia catalog, which enabled the three-dimensional mapping of the Milky Way, is the most complete, yet compiles less than 1% of the galaxy's stars.
]The European satellite Gaia completed the 3D mapping of 1.7 billion stars of the Milky Way and determined the distance between many of them and Earth.
"These data are very important and we believe they will revolutionize astronomy and our understanding of the Milky Way," Uwe Lammers, a scientist responsible for Gaia for the European Space Agency (ESA), told AFP.
The Gaia catalog made it possible to carry out the color, dynamic and three-dimensional cartography of the Milky Way, the most complete one to date, said the Paris Observatory. However, it still compiles less than 1% of the stars in the galaxy.
"With Gaia we can observe the entire history of the Milky Way, it's as if we were practicing archaeoastronomy ... to really reconstruct the history of our Universe," said Günther Hasinger, ESA's science director, in a presentation of these data during a Salon in Berlin.
Launched in late 2013, the satellite, which scans light sources in our galaxy, orbits the sun 1.5 million kilometers from Earth and makes 500 million measurements per day. The data are transmitted to Earth and processed by a consortium of 450 scientists from 20 countries.
Gaia, which has been operational since 2014, had already delivered a first series of results in September 2016. These gave the 1.1 billion star position of the Milky Way, but the satellite was only able to accurately determine the distance of two million stars.
"It was just an appetizer," Frédéric Arenou, a CNRS researcher at the Paris-PSL Observatory, told AFP.
"Now it's a real firework display," said François Mignard, director of research emeritus at the CNRS, responsible for the French team at Gaia.
"Knowing the distance of these stars, we will know its intrinsic brightness, we will know its age, its evolution", explained Frédéric Arenou.
Enthusiasm among astronomers
The new data compiled by Gaia for 22 months - between July 2014 and May 2016 - were published online this Wednesday, so everyone can access this catalog on the Internet.
Across the globe, researchers are "very excited" to discover these new data and start working on them, said Anthony Brown of the University of Leiden, the Netherlands, one of the scientists involved in the Berlin salon.
The Gaia catalog now contains the positions and brightness of 1.7 billion stars. It also provides the distance and movement of 1.3 billion of them, which is considered crucial information.
There is also information about the radial velocities of about 7.2 million stars indicating the rate at which they are moving toward or away from Earth.
On the other hand, Gaia also identified within the solar system 14,000 asteroids and calculated their orbits.
In addition, outside the galaxy has detected 500,000 quasars, extremely energetic and distant objects that emit a colossal energy.
The Gaia satellite is working well and continues to gather data, ESA reaffirmed.
His mission, originally scheduled to last five years, was extended by a year and a half, said Uwe Lammer about this satellite that has the necessary funding to work until 2020.
The cost of this mission is estimated at EUR 740 million for ESA plus the operating costs of the consortium of researchers funded by the countries involved.