2024-10-11 08:45:00
A recent study reveals 55 high-velocity stars ejected from the young star cluster R136, located in the Large Magellanic Cloud (a satellite galaxy of the Milky Way), about 160,000 light-years away. This is the first time that such a large number of high-velocity stars from a single cluster has been detected.
The discovery increases the number of known fugitive stars in this region of the cosmos by up to ten times and represents a new scientific contribution from the European Space Agency’s (ESA) Gaia space telescope, which aims to identify the positions, distances and speeds of most fugitive stars known in this region of the cosmos. of billions of stars in our galaxy.
R136 is a star cluster with particular characteristics, containing hundreds of thousands of stars, including the most massive stars known (up to three hundred times the mass of the Sun), and is part of the largest star-forming region known so far in the world. five million light years.
The Gaia mission is ESA’s most ambitious project for stellar mapping of our galaxy. Since its inception, astronomers from the Department of Quantum Physics and Astrophysics of the University of Barcelona (UB), the UB Institute of Cosmos Sciences (ICCUB) and the Institute of Space Studies of Catalonia (IEEC) have participated to the Gaia project.
In the new research, conducted by experts from the University of Amsterdam, Leiden State University and Radboud University Nijmegen in the Netherlands, Mark Gieles (ICREA, ICCUB, IEEC) has a leading participation. The work was also signed by astronomers from the Royal Belgian Observatory (Belgium), Tel-Aviv University (Israel), the Dutch National Institute for Space Research (Netherlands) and the University of Geneva (Switzerland).
R136 and its surroundings, photographed in infrared light. (Photo: NASA, ESA, CSA, STScI, Webb ERO Production Team)
When star clusters form, collisions between smaller star clusters can cause stars to be expelled from the young cluster. The scientific team, led by Mitchel Stoop, a doctoral candidate at the University of Amsterdam, found that the young R136 cluster has ejected up to a third of its most massive stars outward over the last million years, at speeds exceeding 100,000 km/h. These stars travel up to 1,000 light years from their birthplace before exploding as supernovae at the end of stellar life and giving rise to a neutron star or black hole.
Another surprising result of the study indicates that there was not just one period in which stars were dynamically ejected, but two. According to Stoop, “the first episode occurred 1.8 million years ago, when the cluster formed, and fits with the ejection of stars during the cluster’s formation.” «The second episode occurred only 200,000 years ago and had very different characteristics. For example, the fugitive stars of this second period moved more slowly and did not shoot in random directions as in the first episode, but in a preferred direction,” explains the expert.
Gieles, of ICREA, ICCUB and IEEC and co-author of the research, says that “a lot happens in a short time during the formation of massive star clusters, and the images provide only a snapshot.” He adds that “these new observations of the motion of runaway stars are like a ‘rearview mirror,’ giving us an unprecedented view of what came before.”
It should be remembered that the Dutch astronomer Adriaan Blaauw (1914-2010) identified the first signs of the existence of fugitive stars, that is, stars moving at high speed through the Milky Way galaxy. With this discovery, Blaauw opened one of the most exciting and surprising chapters of research in astronomy and cosmology which revealed its unknowns thanks to a first ESA mission – called Hipparcos – and currently with the Gaia telescope.
The new study is titled “Two waves of massive stars escaping from the young R136 cluster.” And it was published in the academic journal Nature. (Source: University of Barcelona)
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