A team of scientists from the University of Victoria in Canada and Yale University in the United States describe the detection of the faintest star system ever discovered. Appointed Ursa Major III / UNIONS 1 (UMa3/U1), is considered the least intense group of stars ever observed by sciencewhich is located approximately 30 thousand light-years away from Earth.
Because it is an extremely faint and small system, scientists say it has been invisible for a long time; There are only 60 stars in total, which are about 10 light-years across. In addition, UMa3/U1 is 16 times the mass of the Sun and about 15 times less massive than the faintest dwarf galaxy ever detected.
The star system was detected by Keck Observatory’s Deep Imaging Multi-Object Spectrograph (DEIMOS). From this data scientists have confirmed that it is a gravitationally bound systembut they are still trying to confirm whether the discovery is a dwarf galaxy or a star cluster.
UMa3/U1 can be seen in the left part of the image in orbit around the Milky Way.Fonte: CFHT/ S. Gwyn / S. Smith / The Astrophysical Journal
The first detection of UMa3/U1 was made using the Ultraviolet Near Infrared Optical Northern Survey (UNIONS) and Pan-STARRS astronomical instruments. The study was published in the scientific journal The Astrophysical Journal.
“UMa3/U1 is located in the constellation Ursa Major, the home of the Big Dipper. It is located in our cosmic backyard, relatively speaking, about 30,000 light-years from the Sun. UMa3/U1 has so far eluded detection due to its extremely low luminosity.” study lead author and University of Victoria student Simon Smith said in an official statement.
The faintest system in the Milky Way
So far, scientists have not been able to identify exactly what a star system is. One possibility is that UMa3/U1 is a dwarf galaxy with a significantly low amount of visible matter; it would also be rich in dark matter. In this case, science could use this region to study dark matter.
Another possibility is that UMa3/U1 is a a star cluster that is nearing its end, probably due to the gravitational forces of the Milky Way. Scientists suggest that the first option would be considered more important to humanity because it would support the Lambda Cold Dark Matter (LCDM) hypothesis – a theory that explains how the universe works.
“The object is so insignificant that its long-term survival is very surprising. One would expect that the strong tidal forces of the Milky Way’s disk would have destroyed the system by now, leaving no observable remnants. The fact that the system appears intact leads to two equally interesting possibilities. Either UMa3/U1 is a small galaxy stabilized by a large amount of dark matter, or it is a star cluster that we observed at a very special moment before it soon disappeared,” said study co-author and Yale University graduate student Will Cerny.
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