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February 23, 2018, 7:25 am
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Stellar Astrophysics

Gaia Data Release 1

The Gaia spacecraft was launched on December 19th, 2013 to perform a 5-year long all-sky scanning survey that will provide exquisitely accurate astrometry (100 times better than Hipparcos) and photometry for about one billion of Galactic stars down to G ~20.7 (Gaia unfiltered band), and radial velocity for several millions of stars to G~16. This wealth of data  will result in an astronomical catalogue and data archive of unprecedented scope, accuracy and completeness. Gaia main goal is to clarify  the origin, structure, and evolutionary history of our Galaxy, but it will have a significant impact on every branch of astrophysics – from asteroids to dark matter – and also on some aspects of fundamental physics.

After about 1000 days after the launch, the first intermediate Gaia Data Release (GDR1) will be available to the astronomical community on September 14th 2016, 12:30 CEST, at ASDC also will host the GDR1 at, providing additional searching and coss-matching capabilities.

This release is made up by 3 components: 1) an astrometric data set with positions, parallaxes and mean proper motions for about 2 million of the brightest stars in common with the Hipparcos and Tycho-2 catalogues  (the so called Tycho-Gaia Astrometric Solution – TGAS), and positions for additional 1.1 billion sources; 2) G band magnitudes for all sources; 3) the G-band light curves and characteristics of ~ 3000 Cepheid and RR-Lyrae stars observed around the south ecliptic pole with a special scanning law.

A briefing is being organised by ESA at the European Space Astronomy Centre (ESAC) in Villanueva de la Cañada, Madrid, Spain, on Wednesday 14 September 2016, 11:30–13:00 CEST. The programme is available at and the webstreaming at