In 2013, the European Space Agency (ESA) deployed this Gaia The space mission, an observer of the next pay generation that will spend the next five years collecting data on the position, distance and proper speed of the stars. The resulting data will be used to build today’s largest 3D space catalog, totaling 1 billion stars, planets, comets, asteroids, quasars and other celestial objects.
Since the mission began, ESA has issued three initial releases Gaia Data, each of which has led to new research findings and a more detailed map of our galaxy. Based on the third release of mission data, known as Early Data Release 3 (Gaii EDR3), astronomers have created a map of the sky that includes updated data on celestial objects and manages to obtain the total brightness and color of the stars in our galaxy. .
EDR3 was unveiled on December 3, 2020, and includes the position and brightness of 1.8 billion stars, the parallax and proper motion of 1.5 billion stars, and the color of more than 1.5 billion stars. It includes data from more than 1.6 million additional galaxy sources of light, including stars, globular clusters, and more distant galaxies.
New maps
Compared to the previous publication (Gaia DR2) which was published in April 2018, it represents an increase of more than 100 million resources. In addition, the latest release includes improvements in general accuracy and precision measurements. With this updated data, astronomers were able to create a map that showed not only the brightness, but also the density of our galaxy.
While luminous regions correspond to denser concentrations of bright stars, darker regions are parts of the sky where fewer and fainter stars are located. Around the Milky Way galaxy, there are dark patches formed by the foreground clouds of international gas and dust that absorb light from more distant stars. The bright horizontal structure corresponds to the viewed edge of the galaxy’s flattened disk (aka the plane of the galaxy).
Many of these are clouds that hide star nurseries, spreading the nebula to the interclass medium where new stars are born. Around the galactic plane, there are regions of dark patches, corresponding to the foreground clouds of light absorbing the gas and dust of the intestinal tract from more distant stars. And of course, there are bright “beads” in the middle that are ga ense concentrations of stars and gas that are the center of the galaxy.
Then there are the many global and open clusters that appear as bright spots laid across the whole image, some of which are galaxies rather than our own. At the bottom right of the image are two bright objects, the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), two dwarf galaxies that orbit the Milky Way (and are expected to merge with it in a few billion years).
The color of the stars was recreated by combining the total amount of light collected Gaia With all the blue and red light recorded from each patch of the sky. This is the second improvement that EDR3 offers, which is the presence of color information for about 1.5 billion sources (200 million more than DR2).
Galactic collision
Another advancement from this latest information release is that it allows astronomers to detect populations of older and younger stars all the way to the galactic anticenter (the very edge of the galaxy). This allowed astronomers to determine how past mergers affected the formation of galactic disks, and to create computer models that predicted how it would grow over time.
The data show that the outer regions of the disk have a slow moving component of stars heading down the plane and the fast moving component below the plane moves upwards. This pattern came as a complete surprise to astronomers and has strengthened the case for a recent collision between a galaxy and a Sagittarius dwarf galaxy in the recent past.
This dwarf galaxy, which contains millions of stars, is located about 70,000 light years from Earth and orbits the galaxy around its poles. This satellite galaxy is currently being cannibalized by the Milky Way, a process that has brought it closer to our galaxy a few times in the past. With each pass, the galaxy’s gravitational influence is enough to disturb some of the stars in your galaxy’s disk.
The ESA’s Data Processing and Analysis Consortium (DPAC), a pan-European team of expert scientists and software software developers, could already detect a glimmer in the galaxy. They attributed this to past collisions between Sagittarius and the Milky Way 300 to 900 million years ago. This latest data promotes the case for this based on the movement of stars in the Galaxy disk.
Marie Curie Scud Odovska Fellow Teresa Antoza with the Institute of Cosmos Sciences at the University of Barcelona worked with DPAC colleagues on this analysis. “The way disk stars move is different from what we believe,” he said in a recent ESA press release. “As the imitations of all the other writers show, he could be a good candidate for all these distractions.”
Stars of Motion
In addition, researchers at the University of Helsinki created an animation using the proper motion of 40,000 randomly-selected stars over the next 1.6 million years. As it progresses, stars appear to move from the left side of the galaxy and accumulate to the right side, which is the result of the motion of the solar system. Similarly, the apparent speed of the quarters helped to stop the full motion of the solar system.
Professor Markku Pouten of the Finnish Geospatial Research Institute (FGI) said, “The knowledge gained by Gaia affects the accuracy of future satellite navigation. “The position of the satellite in space and the direction of the earth are determined in a reference frame bound in the direction of the quarters. The accuracy and position of the art of the reference frame is important for the accuracy of the researcher. “
As Professor Carrie Muononen of the University of Helsinki and a research professor with FGI explain:
“In animation, short and long trains describe the changes in the position of the stars over 80,000 years. The former is mostly related to distant stars, while the latter is due only to nearby stars. From now on, short trains extend in the long run, and long trains compress in the short run. This is also related to the changing distances of the stars. ”
“This shows the average motion of the solar system, taking into account the surrounding stars. From the Finnish point of view, it is interesting to note that the motion documented by Gaia agrees with the leading research on the motion of the solar system. Friedrich Wilhelm August Gust Argelander (1799-1875) at the 19th century Helsinki Observatory. “
Argeland was a member of the University of Helsinki Observatory, then known as Imperial Alexander University. While the first astronomer to calculate the motion and direction of the solar system around the center of the galaxy. These observations were made while Argelander was at the Turku Observatory from 1827 to 1831, with a precise position of 560 stars.
Further research by DPAC measured how the speed of the solar system changes over time. Using observational speeds of extremely distant galaxies, they estimated that the solar system is moving at a rate of 0.23 nm / s.2 (Compared to the rest of the frame of the universe), which increases by about 115 km in a year.
Star counting
EDR3 data also allowed a new calculation of stars, known as the Gaia catalog of nearby stars, containing 331 312 (objects (approximately 92% stars)) in the 326 light-years of the solar system. This is the first census to be obtained since it was compiled.Initially, it contained only 915 object objects, updated to 3,803 object objects in 1991, and was limited to a distance of 82 light years.
In other words, the New Gaia census contains 100 times the objects at four times the distance. It also offers location, speed and brightness measurements which are more precise size orders than the Glias catalog. As Muinone describes the data-mining process:
“We are responsible for the daily orbits of the asteroids discovered by Gaia. Based on these calculations, ground-based follow-up observations are conducted. Before the data is published, we participate in the validity of Gaia observations of asteroid positions, brightness and spectra.
“Our research with Gaia data focuses on asteroid orbits, orbital periods and polar directions, masses, shapes and surface structural and structural properties. In calculating collision probabilities for asteroids close to Earth, the accuracy of the reference frames is entirely central. “
As the teams precede, this Gaia Project Scientist, added:
“Gaia EDR3 is the result of the tremendous efforts of everyone involved in the Gaia Mission. It is an exceptionally rich data set and I look forward to many discoveries made by astronomers around the world with this resource.. And we’re not done yet; More great data will follow as Gaia continues to measure from orbit.“
This and other new insights are the latest breakthroughs from the data Gaia has collected over the past seven years. EDR3 is the first of a two-part release to be made after the release of Complete Data Release 3 (DR3). Due to the epidemic, the date has been pushed back but is currently expected to happen in the first half of 2022.
At a meeting of the ESA’s Science Program Committee (SPC) on October 1, Gaia The mission was once again extended – this time to December 31, 2022. With mid-term review and confirmation pending by the SPC, the mission could also be extended to 2025. With all the data he provided, it is clear that ESA wants. To continue this mission!
Further reading: ESA, ESA (2), University of Helsinki
