A new star system orbiting our Milky Way has been discovered

A team of astronomers from Yale University and the University of Victoria has made a surprising discovery. It is the faintest star system ever observed orbiting our galaxy, the Milky Way. Called Ursa Major III / UNIONS 1 (UMa3/U1), it is an incredibly dim and ancient group of stars located 30,000 light-years away in the constellation Ursa Major (where the Big Dipper is located). UMa3/U1 is hidden in plain sight UMa3/U1 was invisible for a long time because it was incredibly weak and small. We’re talking about just 60 stars about 10 light-years in diameter. For comparison, one light year is almost 6 trillion miles long. Even if you have a powerful telescope, it’s like trying to spot a few specks of dust floating across a spotlight. hamburger icon logo search icon Product image March 30, 2024 A new star system orbiting our Milky Way has been discovered Written by Sanjana Ghaziveer Earth.com staff A team of astronomers from Yale University and the University of Victoria has made a surprising discovery. It is the faintest star system ever observed orbiting our galaxy, the Milky Way. Called Ursa Major III / UNIONS 1 (UMa3/U1), it is an incredibly dim and ancient group of stars located 30,000 light-years away in the constellation Ursa Major (where the Big Dipper is located). UMa3/U1 is hidden in plain sight UMa3/U1 was invisible for a long time because it was incredibly weak and small. We’re talking about her 60 stars, which are only about 10 light years across. For comparison, one light year is almost 6 trillion miles long. Even if you have a powerful telescope, it’s like trying to spot a few specks of dust floating across a spotlight. Despite its small size, this tiny cosmic neighbor is actually quite close, just 30,000 light-years from Earth. It is located in the constellation Ursa Major (where the Big Dipper is located). Is UMa3/U1 a galaxy or a star cluster?

An important question facing astronomers is whether UMa3/U1 is a true dwarf galaxy or a star cluster. The answer may come down to a mysterious and invisible substance: dark matter. Galaxies are thought to be held together by the gravitational force of dark matter. Dark matter is a type of matter that we cannot see directly but that scientists know exists due to the influence of gravity. On the other hand, gravity alone usually binds stars together to form star clusters, often without the support of dark matter. However, the amazing expansion of UMa3/U1 stars did not lead to their gravitational extinction in the Milky Way. Is dark matter the invisible glue that holds this cosmic relic together? “This object is so small that its long-term survival is quite surprising,” explains Will Cerny, a Yale University graduate student who worked on the study. “One might have expected that the intense tidal forces of the Milky Way disk would tear this system apart by now, leaving no visible debris behind.” UMa3/U1 as a galaxy First, UMa3/U1 may be a true dwarf galaxy, a structure with an incredibly low amount of visible material compared to what is typically observed in such galaxies. This property is an interesting subject for study because it suggests that UMa3/U1 may be composed primarily of dark matter. If UMa3/U1 is indeed a dark matter-rich dwarf galaxy, it could provide valuable insight into the role of dark matter in galaxy formation and evolution. This could support the theory that many galaxies dominated by dark matter exist but remain hidden from our view, potentially revolutionizing our understanding of the structure of the universe. be. star cluster Alternatively, UMa3/U1 could be a star cluster on the verge of collapse. This perspective depicts UMa3/U1 as a cosmic anomaly, a collection of stars that have existed together for billions of years and may now be in the final stages of collapsing due to the gravity of the Milky Way. Observation of such collapse in real time would provide a unique opportunity to study the life cycle of star clusters and the dynamic processes involved in their evolution and collapse. If Scenario 1 proves true, it would provide interesting evidence for the currently dominant theory of how the universe works: the lambda cold dark matter (LCDM) model. This model suggests that when our galaxy formed, it attracted hundreds of small satellite systems that still orbit the galaxy today. UMa3/U1 Space Ghost Hunt “While we don’t know whether future observations will confirm or refute the existence of large amounts of dark matter in this system, we do believe that this object may be the tip of the iceberg.

”The new system is a class of very faint systems that have so far eluded discovery,” Cerny said. The research team used powerful telescopes in Hawaii, including the W. M. Keck Observatory and the Canada-France-Hawaii Telescope (CFHT), to unravel this object’s mysteries. Further observations are required to clarify the identity of UMa3/U1. unknown charm “This discovery could challenge our understanding of galaxy formation, and perhaps even the definition of ‘galaxy,'” said Simon Smith, an astronomy PhD student at the University of Victoria and principal investigator on the study. “There is,” he explains. Source: https://arxiv.org/abs/2311.10134