The Gaia space telescope , of the European space agency, published its third batch of data in June, providing information on almost two billion objects . The implications of the information collected by Gaia are yet to be determined, but they will undoubtedly expand our understanding of the solar system , the stars and exoplanets of the Milky Way, and the galaxies surrounding our own.
The Gaia telescope was launched into orbit in December 2013 and has been collecting data since July 2014 and is located a million and a half kilometers from Earth in the vicinity of what is known as the second Lagrange point of the Earth (where it was recently joined by the James Webb Space Telescope). Gaia turns on itself and thanks to its two optical telescopes and three detectors on board it is capable of determining the chemical composition, temperature, position, speed, mass and color of millions of stars as well as important information on asteroids, comets , exoplanets, galaxies and more.
Gaia has collected information on 1.5 billion stars in our Milky Way , has created the largest catalog of binary stars , has studied some 150,000 objects in the solar system (mainly asteroids, but also planetary satellites), as well as millions of galaxies and quasars. close to the Milky Way.
In this recent batch of data, the information regarding asteroids and smaller bodies in the solar system is multiplied by ten , which will undoubtedly allow us to study more cases of encounters between these bodies, allowing us to study their masses and physical properties in detail. In addition, these data include observations of the spectrum of asteroids for the first time . This spectrum is used to determine the color and composition of asteroids by measuring their brightness at different wavelengths. This allows us to study their origin and evolution since they were formed at the beginning of the solar system. Gaia has collected the spectra of about 60,000 asteroids , about ten times more spectra than we have managed to collect so far with different methods.
On the other hand, it is expected that the data provided by Gaia will allow us to identify around 20,000 new giant exoplanets , measuring how their presence alters the position of the stars they orbit. This amount would be 4 times higher than the number of exoplanets (of all types) detected so far, during the last 30 years. If we successfully reached this number, we would have detected virtually all exo-Jupiters in the vicinity of the solar system . This will allow us to study the formation of solar systems with arrangements like our own , determining the prevalence of our configuration (rocky planets in the interior and gas giants in the exterior). The first detection of its kind allowed the discovery of the closest gas giant to the solar system, located just 12 light years away .
The enormous sensitivity of Gaia not only allows us to measure the movement of the stars that make up the Milky Way, but also of stars located in some of the satellite galaxies that surround it. Considerably smaller in size than our own galaxy, these galaxies orbit our own, taking hundreds of millions of years to complete one orbit . This is why it is difficult to establish whether they are true satellites or whether the paths of both systems have simply crossed.
Observing the stars of the Milky Way we can determine with great precision the mass and the distribution of matter that compose it. Combining this information with observations of the stars that make up these satellite galaxies we can narrow down more precisely which are true satellites and which are not . This will allow us to compare our cosmic neighborhood with current cosmological models and even deepen our study of the dark matter present in the Milky Way.
In addition, Gaia has collected information on more than a million and a half quasars . These objects, in addition to their astrophysical interest, have a practical use that is to serve as a reference in any created sky map . Being such distant and bright points, they can be considered as fixed points on which to define any reference system. One of these systems, known as ICRF3 (International Celestial Reference Frame) is currently used to determine the position of any celestial object in the sky as well as the artificial satellites that surround our planet. With the new data , an even more precise reference system can be created , allowing us to improve the sensitivity and precision of the thousands of satellites in orbit (and the tens of thousands expected to be launched in the coming decades).
The data collected by the Gaia telescope is by far the most abundant and precise of its kind ever obtained . This telescope represents the not so attractive side of astronomy , compared to Hubble or James Webb. However, all this information is even more important in our study of the universe and our place in it, although the results obtained are not as striking as the spectacular images obtained by the other two telescopes mentioned.
Reference:
GAIA DATE RELEASE 3 (GAIA DR3), June 13, 2022, ESA
Gaia Collaboration, A. Vallenari et al, 2022, Gaia Data Release 3. Summary of the content and survey properties, A&A, DOI: https://doi.org/10.1051/0004-6361/202243940
