Star formation broke out in the Milky Way 2-3 million years ago.



Star formation broke out in the Milky Way 2-3 million years ago.

The region of the Rho Ophiuchi star formation observed by the Gaia satellite of the ESA. The bright spots are stellar clusters with the mbadive and younger stars of the region. The dark filaments track the distribution of gas and dust, where the new stars are born. This is not a conventional photographic image, but the result of the integration of all the radiation received by the satellite during the 22 months of continuous measurements through different filters in the spacecraft. Credit: ESA / Gaia / DPAC, CC BY-SA 3.0 IGO

A team led by researchers from the Institute of Cosmos Sciences of the University of Barcelona (ICCUB, UB-IEEC) and the Astronomical Observatory of Besançon badyzed the data from the Gaia satellite and found that in the Milky Way there was a great explosion of formation of stars in the Milky Way. Millions of years ago. During this process, more than 50 percent of the stars that created the galactic disk could have been born. These results are derived from the combination of the distances, colors and magnitude of the stars that Gaia measured with models that predict their distribution in our galaxy. The study has been published in the journal. Astronomy and Astrophysics.

As a flame vanishes when there is no gas in the cylinder, it is predicted that the rate of star formation in the Milky Way, fed by the deposited gas, will decrease slowly and continuously as the existing gas is extinguished. The results of the study show that, although this process took place during the first 4,000 million years of formation of the Milky Way disk, an explosion of star formation or stellar baby boom reversed this trend. A gas-rich satellite galaxy merged with the Milky Way and could have introduced new fuel and reactivated the process of star formation. This mechanism would explain the distribution of distances, ages and mbades that are estimated from the data taken from the Gaia satellite of the European Space Agency.

"The time scale of this star formation burst, along with the large star mbad involved in the process, billions of solar mbades, suggests that the disk of our galaxy did not have a constant and paused evolution. external disturbance, that began about 5 billion years ago, "said Roger Mor, ICCUB researcher and first author of the article.

"We have been able to discover this by badyzing the precise distances of more than 3 million stars in the solar environment," says Roger Mor. "Thanks to these data, we were able to discover the mechanisms that controlled evolution more than 8 to 10 billion years ago in the disk of our galaxy, which is nothing more than the bright band we see in the sky on a dark night without light pollution. " As in many fields of research these days, these findings are possible thanks to the availability of the combination of a large amount of data of unprecedented precision and many hours of computing.

The cosmological models predict that our galaxy would have been growing due to the fusion with other galaxies, a fact that has been declared by other studies using data from Gaia. One of these combinations could be the cause of the severe outbreak of star formation that was detected in this study.

Star formation broke out in the Milky Way 2-3 million years ago.

The distribution of 3 million stars used in this study to detect star formation exploded 2 or 3 billion years ago. Gaia provided the distance for each of these objects in the galactic disk. Below, an outline of the spiral arms of the Milky Way. Credit: University of Barcelona.

"In reality, the peak of star formation is so clear, unlike predictions prior to the availability of Gaia data, that we thought it was necessary to deal with its interpretation together with experts in cosmological evolution of external galaxies," says Francesca Figuerars, Professor of the Department of Quantum. Physics and astrophysics of the UB, member of ICCUB and signer of the article.

Santi Roca-Fàbrega, from the Complutense University of Mardid, an expert in stellar modeling and co-author, said: "The results obtained coincide with what current cosmological models predict, and what is more, our galaxy seen from the eyes of Gaia is an excellent cosmological Laboratory where we can test and compare models on a larger scale in the universe ".


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More information:
R. Mor et al, Gaia DR2 reveals an explosion of star formation in the disk 2-3 Gyr ago, Astronomy and Astrophysics (2019). DOI: 10.1051 / 0004-6361 / 201935105

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