The Gaia Space Telescope is an asteroid science rock

The European space mission Gaia has created unprecedented amounts of new, advanced and detailed information for the Milky Way galaxy and nearly two billion objects in the surrounding cosmos. Monday’s Gaia Data Release 3 revolutionizes our knowledge of the solar system and the Milky Way and its satellite galaxy.

The Gaia space mission of the European Space Agency ESA is creating a very accurate three-dimensional map of our galaxy, the Milky Way, observing about two billion stars or about one percent of all the stars in our galaxy. Gaia was launched in December 2013 and has been collecting scientific data since July 2014 On Monday 13 June, ESA released Gaia Data in Data Release 3 (DR3) Finnish researchers were heavily involved in the publication.

Data from Gaia, for example, allow to find out the orbits and physical properties of asteroids and exoplanets. The data helps to uncover the origin and future evolution of the solar system and the Milky Way, and helps us to understand the evolution of the planets and our position in the cosmos.

Gaia slowly revolves around its axis in about six hours and is composed of two optical space telescopes. Three scientific instruments allow precise determination of stellar position and velocity as well as spectral properties. Gaia lives approximately 1.5 million kilometers away from the Earth in the opposite direction to the Sun, where it orbits the Sun along the Earth near the so-called Sun-Earth Lagrange Point L2.

On June 13, 2022, the Gaia DR3 was significant throughout astronomy. About 50 scientific research papers have been published with DR3, nine of which are dedicated to highlighting the extraordinary potential of DR3 for future research.

New DR3 data includes, for example, chemical composition, temperature, color, mass, light, age and radial velocity of stars. DR3 contains the largest catalog of binary stars created for the Milky Way, more than 150,000 solar system objects, mostly asteroids but planetary satellites, and millions of galaxies and quasars outside Way Milky.

“There is so much revolutionary progress that it is difficult to identify a single most significant progress. Based on Gaia DR3, Finnish researchers will change the design of our solar system’s asteroids, the exoplanets of our Milky Way galaxy, and the stars as well as the galaxies. Including themselves, the Milky Way and its surrounding satellite galaxy. Back on our planet, Gaia will create an ultra-accurate reference frame for navigation and location, “said Carrie Muinonen, a professor at the University of Helsinki Academy.

Gaia and asteroids

A ten-fold increase in the number of asteroids reported in Gaia DR3 compared to DR2 means a significant increase in the number of close encounters between asteroids identified by Gaia. These nearby encounters can be used to estimate asteroid mass, and we expect a significant increase in the number of asteroid masses using Gaia DR3 astrometry, especially when combined with astrometry obtained by other telescopes.

In the conventional calculation of the orbit of an asteroid, the asteroid is assumed to be a point-like object and its size, shape, rotation and surface light scattering properties are not taken into account. The Gaia DR3 astronomy is so precise that the angular offset between the center of the asteroid’s mass and the center of the Gaia visible sunlight region must be taken into account. Based on the Gaia DR3, the offset was attested to the asteroid (21) Lutetia (Fig. 2). ESA’s Rosetta space mission filmed Lutetia during a July 10, 2010 flyby. A rotation period, rotation pole orientation, and detailed size models have emerged with the help of Rosetta Lutetier’s images and ground-based astronomical observations. When physical modeling is combined with orbital calculations, methodological errors are removed and, unlike conventional calculations, all observations can be combined to solve orbitals. Therefore, Gaia astrometry provides information about the physical properties of asteroids. These features must be considered when using physical models or empirical error models for astronomy.

Gaia DR3 includes spectral observation for the first time. The spectrum measures the color of the target, such as brightness at different wavelengths. A particularly interesting feature is that the new version contains about 60,000 spectra of asteroids in our solar system (Figure 3). The spectrum of asteroids contains information about their structure and hence their origin and the evolution of the entire solar system. Prior to the Gaia DR3, only a few thousand asteroid spectra were available, so Gaia would multiply the amount of data beyond the scale.

Gaia and Exoplanet

Gaia is expected to detect 20,000 giant exoplanets by measuring their gravitational effects on the motion of their host stars. It will find virtually all Jupiter-like exoplanets in the solar system over the next few years and will determine the frequency of architectures like the solar system. Guy’s first astrometric detection was a giant exoplanet around the Episillon indie A, just 12 light-years away, the closest Jupiter-like exoplanet. The first such detection is possible because the acceleration seen in radial velocity studies can be combined with motion data from Gaia to determine the planet’s orbit and mass.

Gaia and the galaxy

The Gaia DR3’s microarcsecond resolution provides precise measurement of star speeds not only in our own galaxy, the Milky Way, but also for the many satellite galaxies that surround it. From the motion of the stars in the Milky Way itself, we can accurately measure its mass and with the help of the exact motion of the satellites we can now accurately determine their orbits. This allows us to look at both the past and the future of the Milky Way galactic system. For example, we know which of the galaxies around the Milky Way are true satellites and which are just passing through. We can also study whether the evolution of the Milky Way is compatible with the cosmic model, and in particular, whether the orbits of the satellites coincide with the ideal model of dark matter.

Gaia and reference frame

The International Cosmic Reference Frame, ICRF3, is based on the position of several thousand quasars determined by very long baseline interferometry (VLBI) over radio wavelengths. ICRF3 is used to obtain the coordinates of celestial objects and to determine the orbits of satellites. ICRF3 quasars are also specific points in the sky that can be used to determine the exact orientation of the Earth in space at any time. Without this information, for example, satellite location will not work.

Gaier’s data contains about 1.6 million quasars, which can be used to create a more accurate visible-light sky reference frame to replace the current. In the future, this will affect the accuracy of satellite positioning and earth exploration satellite measurements.

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