ESA’s Gaia Mission Releases Its Third Full Dataset

by johnsmith

Gaia’s data release 3 (DR3) contains new and improved details for almost 2 billion stars in our Milky Way Galaxy as well as for a subset of solar system objects and extragalactic sources.

This image shows four (radial velocity, interstellar dust, radial velocity and proper motion, and chemical) maps made with Gaia’s data release 3. Image credit: ESA / Gaia / DPAC.

This image shows four (radial velocity, interstellar dust, radial velocity and proper motion, and chemical) maps made with Gaia’s data release 3. Image credit: ESA / Gaia / DPAC.

ESA’s Gaia star-mapping satellite was launched on December 19, 2013 on board a rocket from Europe’s Spaceport in Kourou, French Guiana.

It operates in an orbit around the Lagrange 2 (L2) point, located 1.5 million km behind the Earth in the direction away from the Sun.

At L2 the gravitational forces between the Earth and Sun are balanced, so the spacecraft stays in a stable position, allowing long-term essentially unobstructed views of the sky.

Equipped with 106 CCDs forming the equivalent of a camera with a resolution of a billion pixels, it surveys 50 million stars per day, each time carrying out ten measurements, which represents a total of 500 million data points per day.

Gaia’s first data release, based on just over one year of observations, was published on September 14, 2016. It included the position and brightness for 1.1 billion stars, but distances and motions for just the brightest two million stars.

The second data release was made public on April 25, 2018 and included the positions on the sky for approximately 1.7 billion stars.

“Unlike other missions that target specific objects, Gaia is a survey mission,” said Gaia project scientist Dr. Timo Prusti, of ESA.

“This means that while surveying the entire sky with billions of stars multiple times, Gaia is bound to make discoveries that other more dedicated missions would miss.”

“This is one of its strengths, and we can’t wait for the astronomy community to dive into our new data to find out even more about our Galaxy and its surroundings than we could’ve imagined.”

The newest data release from the Gaia mission contains new and improved details for almost two billion stars.

It includes new information including chemical compositions, stellar temperatures, colors, masses, ages, and the speed at which stars move towards or away from us (radial velocity).

Much of this information was revealed by the newly released spectroscopy data, a technique in which the starlight is split into its constituent colors.

The data include millions of galaxies and quasars outside the Milky Way and special subsets of stars, like those that change brightness over time.

The release also presents the mass and evolution of more than 800,000 binary systems — the largest catalogue yet of binary stars, while a new asteroid survey comprising 156,000 rocky bodies is digging deeper into the origin of our Solar System.

It reveals information about 10 million variable stars and mysterious macro-molecules between stars.

One of the most surprising discoveries coming out of the new data is that Gaia is able to detect starquakes that change the shapes of stars, something the observatory was not originally built for.

Previously, Gaia already found radial oscillations that cause stars to swell and shrink periodically, while keeping their spherical shape.

But Gaia has now also spotted other vibrations that are more like large-scale tsunamis.

These nonradial oscillations change the global shape of a star and are therefore harder to detect.

Gaia found strong nonradial starquakes in thousands of stars. Gaia also revealed such vibrations in stars that have seldomly been seen before.

These stars should not have any quakes according to the current theory, while Gaia did detect them at their surface.

“Starquakes teach us a lot about stars, notably their internal workings,” said Dr. Conny Aerts, an astronomer at KU Leuven.

“Gaia is opening a goldmine for ‘asteroseismology’ of massive stars.”

A series of papers describing the new Gaia data and their validation process appears in a special issue of the journal Astronomy & Astrophysics.

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