Posted 21 June 2022 in Astronomy, News, Space.

The European Space Agency’s (ESA’s) Gaia mission has revealed stunning new insights into our galaxy, the Milky Way, in the third release of mission data on 13 June. Among the highlights are new and improved details about nearly 2 billion stars, the largest ever catalogue of binary stars and evidence of an unexpected stellar motion in many stars dubbed ‘starquakes’.

RHEA is delighted to see the results emerging from the new data release. RHEA engineers are involved in the data processing and management, testing and cataloguing of Gaia data, and its inclusion in ESASky, a discovery portal that provides access to images and information about the entire sky through an online celestial atlas.

ESA’s Gaia mission is building the most precise three-dimensional map of our galaxy ever created by measuring the position, distance and velocity of billions of astronomical objects with unprecedented accuracy. Gaia was launched in 2013. Data is released in phases, with two previous releases in 2016 and 2018, and an early release of some phase 3 data in 2020.

New star information

Gaia data release 3 includes information on the luminosity, chemical composition, temperature, mass and age of stars, much of which has come from spectroscopy data. It also reveals the radial velocity of more than 33 million stars – a five-fold increase on the previous data release – which tells us how fast each star is moving away from or towards Earth.

The chemical composition of stars – in particular what proportion of materials other than hydrogen and helium they contain – can reveal their origin. Some are made of primordial material, while others, including our Sun, are made of matter that was once part of older generations of stars. Gaia’s data also lets us identify stars in our galaxy that were born in other galaxies.

The new binary star catalogue includes information on the mass and evolution of over 800,000 binary systems. One of the benefits of having data on binary star systems is that it enables the mass of each star to be determined directly through observational data, instead of using models, which is less accurate.

Starquakes

Gaia had previously provided data showing that stars oscillate radially, causing them to swell and shrink. However, they remain spherical during such oscillations. Analysis of data from this latest release shows that some stars also appear to experience ‘starquakes’ – tiny motions on their surface that change the overall shape of the star. Gaia detected such non-radial oscillations on thousands of stars.

Assembling and releasing the data

RHEA operations engineers and scientists play an important role at the Gaia Science Operations Centre (SOC) at ESAC, with responsibility for the reception and initial processing of Gaia data and its daily distribution to Gaia data processing centres across Europe. They are also responsible for management of the extremely databases of data from all ESA missions.

“The new Gaia data release is astounding in terms of the extra information it has produced, both in terms of broadening the existing catalogue of data and revealing new details about our galaxy,” said Javier Espinosa, RHEA Group DevOps Software and Database Engineer working at ESA’s European Space Astronomy Centre (ESAC) Science Data Centre (ESDC). “It is exciting to now be able to make some of this available through ESASky, which acts as an interface for all astronomy missions. Through ESASky, you can look at objects across the sky that have been observed by ESA missions, including Gaia, and navigate in a similar way to using Google Maps.”

Speaking on behalf of the Survey ESDC team, RHEA’s Sara Nieto, SCO-08 Survey Technical Lead, said: “Thousands of concurrent users are accessing the Gaia DR3 archive to make scientific discoveries that will be published in the coming months and years, so we are all very excited!”

Gaia sky maps

A selection of images of our galaxy, the Milky Way, showing different examples of what can be determined from the data in the latest Gaia release.