The subject of the space telescope shakes the science of asteroids – ScienceDaily

The European Theme space mission has created unprecedented new, improved, and accurate data for nearly two billion objects in the Milky Way galaxy and surrounding cosmos. Topic Data Release 3 on Monday revolutionizes knowledge of the Solar System and the Milky Way and its satellite galaxies.

The ESA European Space Agency’s space mission is building an ultra-accurate three-dimensional map of our Milky Way galaxy, observing nearly two billion stars or about one percent of all stars in our galaxy. The topic was launched in December 2013 and has collected scientific data for July 2014. On Monday, June 13, ESA released the Gaia data in the Data Release 3 (DR3) section. Finnish researchers were very involved in the release.

Subject data, for example, allow the orbits and physical properties of asteroids and exoplanets to be derived. The data help to explain the origin and future evolution of the Solar System and the Milky Way, and help us to understand the evolution of the stars and the planet and our place in the cosmos.

The subject rotates slowly around its axis in six hours and consists of two optical space telescopes. The three scientific instruments allow us to accurately determine the positions and velocities and spectral properties of stars. The subject lives 1.5 million kilometers from the Earth in the opposite direction to the Sun, where it orbits the Sun near the Earth near the so-called Lagrange L2 point.

The topic of DR3 on June 13, 2022 was significant in astronomy. About 50 scientific papers are being published with DR3, nine of which have been devoted to highlighting the outstanding extraordinary potential for future DR3 research.

The new DR3 data includes, for example, the chemical composition of stars, temperature, color, mass, brightness, age, and radial velocities. DR3 contains the largest binary star catalog ever on the Milky Way, with more than 150,000 objects in the Solar System, mostly asteroids but also planetary satellites, as well as millions of galaxies and quasars beyond the Milky Way.

“There are so many revolutionary advances where it is difficult to determine any significant advances. Based on DR3, Finnish researchers will change the view of asteroids, exoplanets and stars in our Solar System in our Milky Way galaxy, as well as galaxies themselves. Returning to our homeland, Gaia will create an ultra-precise frame of reference for navigation and location, “said Professor Karri Muinon of the University of Helsinki.

Subject and asteroids

The fact that the number of asteroids indicated by the subject in DR3 has increased tenfold compared to DR2 means that the number of close encounters between asteroids detected by the subject has increased. These close encounters can be used to estimate the mass of asteroids and we hope to significantly increase the number of asteroid masses that will be extracted using Gaia DR3 astrometry, especially in combination with astrometry obtained by other telescopes.

In the conventional computation of the orbit of an asteroid, the asteroid is assumed to be a point-shaped object and its size, shape, rotation, and scattering properties of surface light are not taken into account. The subject DR3 astrometry, however, is so accurate that the angular displacement between the center of mass of the asteroid and the center of the Sun’s illumination and the field of view of the subject must be taken into account. Based on the DR3 theme, the displacement (21) is assured for the asteroid Lutetia (Figure 2). The ESA Rosetta space mission took a picture of Lutetia on a plane on July 10, 2010. With the help of Rosetta Lutetia images and astronomical observations of the Earth, the period of rotation, the orientation of the rotation pole, and the exact shape model were extracted. When physical modeling is incorporated into orbit computation, systematic errors are removed and, contrary to conventional computation, all observations can be incorporated into the orbit solution. As a result, Gaia astrometry provides information about the physical properties of asteroids. These properties should be considered using physical models or empirical errors for astrometry.

Topic DR3 includes spectral observations for the first time. The spectrum measures the color of the target, that is, the brightness at different wavelengths. A particularly interesting feature is that the new version contains about 60,000 asteroids in our Solar System (Figure 3). The spectrum of asteroids contains information about their composition, and therefore about their origin and the evolution of the entire solar system. Before Gaia DR3, only thousands of asteroid spectra were available, so Gaia will multiply the number of data by more than one order of magnitude.

Subject and exoplanets

The subject is expected to detect 20,000 giant exoplanets by measuring their gravitational effect on the motion of their host stars. This will allow you to find almost all of the Jupiter-like exoplanets in the Solar District in the coming years, and to determine how common the similar architecture of the Solar System is. The first detection of an astrometric subject was a giant exoplanet around the Indi A epsilon, the closest Jupiter-like exoplanet that is only 12 light-years away. Such first detections are possible because the acceleration observed in radial velocity surveys can be combined with the motion data of the subject to determine orbits and planetary masses.

Theme and galaxies

Subject matter The microarcusecond resolution of DR3 provides accurate measurements of stellar motions, not only within our Milky Way galaxy, but also for many of the surrounding satellite galaxies. From the motion of the stars in the Milky Way itself, we can accurately measure their mass, and with the proper motion of satellites, we can now accurately determine their orbits. This looks at the past and future of the Milky Way galaxy system. For example, we can find out which of the galaxies orbiting the Milky Way are the actual satellites, and which ones are passing through. We can also investigate whether the evolution of the Milky Way is consistent with cosmological models, and in particular whether the orbits of satellites fit the standard model of dark matter.

Subject and reference marks

The International Sky Reference Framework, ICRF3, is based on the position of several thousand quasars determined by radio wavelengths by Very Long Baseline Interferometry (VLBI). ICRF3 is used to obtain the coordinates of celestial objects and to determine the orbits of satellites. ICRF3 quasars are also fixed points in the sky and can be used to determine the exact orientation of the Earth in space at any time. Without this information, for example, the location of the satellites would not work.

The data for the subject is about 1.6 million quasars, and can be used to create a more accurate Heavenly Reference Framework in visible light, replacing the current one. In the future, this will affect the location of the satellites as well as the accuracy of the measurements of the satellites that are exploring the Earth.


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