New data, including the exact location of the sun’s 300,000 closest neighbors, has been added to the most accurate map of the Milky Way, with the help of astronomers at the ELKH Astronomical and Earth Sciences Research Center (CSFK).

One of the flagships of the European Space Agency (ESA), the Gaia Space Telescope has been working for years to determine where and how far from our galaxy, at least a billion or one percent, of the hundreds of billions of stars that make up the Milky Way.

Since 2014, the space telescope has been continuously collecting highly accurate position and brightness measurements. In 2018, European astronomers published the first major catalog based on space telescope data, which had a major impact on stars and the Milky Way research: in just two years, more than 3,500 articles used the data then available. According to a statement from CSFK, a new catalog has now been compiled by a consortium of hundreds of astronomers who are working to process the data and process even more, nearly three years of observational data. Four CSFK researchers: László Molnár, Emese Plachy, László Szabados and Elza Szegedi-Elek took part in the work as members of the consortium.


Anthony Brown (Leiden University, The Netherlands), head of the Gaia scientific consortium, said the work was scheduled to be completed in September, but could not be due to the epidemic. The data, which was finally completed in December, already includes the positions and brightness of more than 1.8 billion stars, as well as the distances of approximately 1.5 billion stars, far exceeding preliminary expectations, they write. In the new catalog, the researchers paid special attention to mapping the Sun’s neighbors in one hundred pars, or 326 light years.

As they write, the challenge here was mainly to identify the smallest, faintest stars: most of our neighbors are tiny red dwarf stars, which are not necessarily visible even with smaller binoculars. After careful examination of the data, it appeared that more than 300,000 stars fall in this space, about ten times the number of our known star neighbors. But if you just look at the number of stars within about 80 light years (25 pars), that doubled as well, they said.

Through Gaia’s near-star catalog, we finally have the opportunity to get an accurate picture of not only how many and which other stars surround the sun, but where they came from and where they are going. “

– they emphasize.

For example, based on the speed of the stars, we have been able to identify more than 16,000 pairs moving together, that is, a binary star system. But researchers have also calculated where the stars in the Milky Way will continue to orbit. It turns out that, like the sun, most of them revolve around the Milky Way disk, but a small portion of them are on their own, passing steep trails right next to us. But each star’s trajectory is a little different.

[Megtalálták a galaxis maradványait, ami összeütközött a Tejútrendszerrel]

In addition to nearby stars, stars on the edge of the Milky Way and beyond played a key role in the 2020 data release. ”The edge of the Milky Way turned out to be not just dusty and dull tips: in fact, it is the edge of the Milky Way disk that is most is understood when other smaller galaxies collided. The spatial distribution and velocities of the stars preserve these collisions to this day, the traces of which require a lot of work to accurately detect and model, “the astronomers emphasize.

As they write, the history of our two largest companion galaxies, the Small and Large Magellanic Clouds, turned out to be equally complex. “With Gaia we are already able to map how the two galaxies rotate and how the young and old stars move in them, inside or outside the spiral arms. In addition, the stars of the bridge connecting the two clouds showed. that the Little Magellan flow from the cloud to the Great “. These new Gaia data now also provide ample work for astronomers who are building galaxies with computers and creating theoretical models, they add.

The great Magellanic clouds


Another result, which the researchers didn’t even expect, from 34 months of data, was measuring the acceleration of the solar system. It has long been known how fast the sun and its planets orbit the Milky Way: we travel 230 kilometers every second, and it still takes over 200 million years to circle our galaxy. However, it is much more difficult to measure the extent to which this circulation rate changes. The farthest celestial objects visible to Gaia, the apparent shifts of very bright but very distant galaxies, eventually led to astronomers.

“Based on the results, we are accelerating straight to the center of the Milky Way, but that does not mean that we are slowly falling towards the central black hole, but that gravity is curving the motion of the solar system to stay around it,” they write. The calculated acceleration turned out to be “astonishingly small”: at such a rate, it would take well over four hundred years to pick up the speed of a regular runner, the statement said.

The consortium, and thus several members of the CSFK, are already working on the next catalog, scheduled for 2022. According to the announcement, the space telescope is expected to be able to collect measurements by 2025, so our map of the Milky Way will be out by the end of the 1920s. be further refined. The five articles that present the results are Astronomy and Astrophysics published in a magazine.

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