Gaia @ ROB



Belgian astronomers help to compile the most detailed 3D map of our galaxy (press release)

Gaia Data Release 2 was made public on 25 April 2018 and is available through the Gaia Archive


copyright: ESA/Gaia/DPAC


Based on 22 months of observations, the second release of Gaia's data contains the position on the sky and brightness of 1 692 919 135 stars, as well as measurements of the parallax and proper motion of 1 331 909 727 stars.

It also includes a wide range of additional information: the colours of 1.38 billion stars; the radial velocities of 7 224 631 stars; information about 550 737 variable sources; an estimate of the surface temperature for 161 497 595 stars, of the extinction – a measure of the amount of dust along the line of sight – for 87 733 672 stars, and of the radius and luminosity of 76 956 778 stars.

Closer to home, the new data set also contains the position of 14 099 Solar System objects – mostly asteroids – based on more than 1.5 million observations.

A description of the contents of Gaia DR2 is online available



The participation of the ROB in the preparation of Gaia started as early as 1998 in various working groups, and continued after DPAC definition in CU4, CU6, CU7, and CU8. (CU = Coordination Unit ; DPAC = Data Processing and Analysis Consortium)

The members of the Gaia ROB have different domains of expertise that encompass the physics and dynamics of intermediate mass to massive stars (O, Be, B[e], A stars), of variable and multiple stars, and asteroids. Our contributions imply work package management and software development.

In CU8, we are dealing with the identification and classification of peculiar and emission-line stars. Our tasks include the computation and delivery of synthetic spectra computed with different codes, the data mining in existing catalogues, the observation of peculiar stars and the subsequent data reduction as part of our GBOG (Ground Based Observations for Gaia) activities.

For CU7, our staff is working on variability characterization and is conceiving algorithms enabling the search and determination of periods of variable signals.

We are also involved in specific objects studies. As members of CU6, we are developing and proposing various approaches allowing the extraction of single and multiple stars radial velocities and projected rotation velocities from single transit RVS (Radial Velocity Spectrometer) data.

And in CU4, our team is taking care of the astrometric reduction of Solar system objects (SSOs). Our efforts and participation to the Gaia DPAC are supported by the Belgian ESA PRODEX program.


Successfully launched on 19 December 2013, 9h12m18s UTC!