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Save the date: Gaia's second data release set for 25 April

on 31 January 2018

Following the release of the first catalogue in 2016, ESA's Gaia mission will publish its long-awaited map of more than 1 billion stars in our Galaxy on 25 April 2018.

Launched on 19 December 2013, and in routine science operations since 25 July 2014, Gaia has been mapping the positions and motions of stars at an accuracy level never before achieved, far below one thousandth of an arcsecond. Such an accuracy relies on the satellite's extraordinary equipment, long stretches of uninterrupted observations, and a collaboration of about 450 scientists and software experts who are entrusted with the complex task of analysing and processing the data.

The first release, which included the positions on the sky for 1 billion stars plus an estimate of the distance (parallax) and proper motion for a subset of 2 million bright stars, has already had a profound impact on the global astronomical community and generated hundreds of scientific publications.

But it is the second release of Gaia data that astronomers across the world are eagerly looking forward to.

Based on 22 months of data collected between 25 July 2014 and 23 May 2016, it will contain the positions, parallaxes, and proper motions for more than 1.3 billion stars, as well as G magnitudes for all of them. It will also contain a measure of each star's colour – the BP magnitude, recorded by the blue photometer, and the RP magnitude, recorded by the red photometer – for the vast majority of sources.

And there is more: the second Gaia release will also include: radial velocities for more than six million stars; temperature estimates for about 150 million stars; the light curves of more than half a million variable stars, including Cepheids and RR Lyrae; and the positions of more than 13 000 objects in the Solar System – mostly asteroids – based on more than 1.5 million observations.

This sensational data set will enable astronomers to explore the composition, formation and evolution of our Milky Way galaxy like no other stellar catalogue has before.

The release will be accompanied by a media briefing to take place at the ILA Berlin Air and Space Show in Germany.

Image credit: ESA/ATG medialab