Gaia satellite to build the most detailed 3D map of the Milky Way ever made

By AG Staff Writer 15 September 2016
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The European Space Agency has charted more than a billion Milky Way stars – on its way to building the most detailed 3D map of our galaxy ever made.

YESTERDAY, THE EUROPEAN Space Agency (ESA) released the first catalogue of more than a billion stars from its Gaia satellite – the largest all-sky survey of celestial objects to date.

Launched in December 2013, the goal of the Gaia mission is to build the largest, most precise 3D map of our galaxy ever made.

With three years left of the mission, the data contained in this first release alone is unprecedented – the precise position in the sky and brightness of 1142 million stars charted by Gaia over a 14 month period. The distances and motions across the sky for more than two million stars was also published.

Already, this new catalogue is twice as precise and contains 20 times more stars than the previous definitive reference, the Hipparcos Catalogue from an ESA mission launched in 1989.

gaia map esa

An all-sky view of stars in the Milky Way and neighbouring galaxies, based on the first year of observations from ESA’s Gaia satellite. This map shows the density of stars observed by Gaia in each portion of the sky. Brighter regions indicate denser concentrations of stars, while darker regions correspond to patches of the sky where fewer stars are observed. (CREDIT: ESA/Gaia/DPAC)

“Today’s release gives us a first impression of the extraordinary data that await us and that will revolutionise our understanding of how stars are distributed and move across our galaxy,” said Alvaro Giménez, ESA’s Director of Science.

Carrying the largest digital camera ever taken into space at almost one billion pixels, Gaia will observe one billion stars about 70 times each over five years – an average of about 40 million observations per day. The resulting data-processing challenge is enormous, with data expected to exceed 1 Petabyte (1 million Gigabytes) by the end of the mission in 2019.

As well as being processed and analysed by a consortium consisting of more than 400 individuals who will contribute a combined total of 2000 years effort, the database is publically available online for researchers and curious enthusiasts.

“Not only is Gaia massively expanding the number of stars for which we have information, it is doing it at unprecedented accuracy compared to previous missions such as Hipparcos, and even reaching beyond the confines of the Milky Way,” said Jarrod Hurley, an astrophysicist at Swinburne University of Technology in Melbourne, Australia.

“For me personally, the ability of Gaia to peer inside open [star] clusters to provide accurate data on the positions and velocities of cluster members is particularly exciting,” he said.

Fifteen scientific papers decribing Gaia’s first data release are published in a special edition of the journal Astronomy & Astrophysics

Watch the ESA’s animated visualisation of how Gaia scanned the sky during its first 14 months of operations:

The oval represents a projection of the celestial sphere, with different portions of the sky gradually appearing, according to when and how frequently they were scanned by Gaia. (Source: ESA/Gaia/DPAC)