A faint trail of stars in a distant galaxy has helped astronomers make a discovery that could provide new clues about dark matter and how galaxies form and evolve. Researchers have found a barely visible stellar trail in archival data from the Hubble Space Telescope. It is the first globular cluster star stream to be discovered outside the Milky Way Galaxy. This stream is located in a galaxy located about 115 million light-years from Earth, and is reportedly the remains of a dense cluster of stars slowly disintegrating under the gravity of its host galaxy. CNN.
As the stars gradually separate from the star cluster, the remaining stars form a long, thin star stream. Astronomers have discovered dozens of these stellar streams in the Milky Way, but many remain undetected due to their extremely faint light.
Details of this discovery were published in a study in the journal nature. Stellar flow modeling helped scientists map the galaxy called UGC 9050-Dw1 and study its gravitational field.
The galactic gravity affects the shape and motion of the stellar stream. Based on this, the researchers studied the galaxy’s gravitational field and estimated its total mass, which includes both visible matter – such as stars – and dark matter.
Co-author Julie Kjell-Holme described their discovery that they had found a stellar stream outside the Milky Way as “very exciting.”
She noted that the team then began to consider possibilities for further research.
The true nature of dark matter remains a mystery to scientists. Although it cannot be observed directly, the effects of its gravity on stars and galaxies can be detected.
According to Kjell Holm, scientists estimate that dark matter makes up about 80 to 85 percent of the universe, so efforts to understand it are crucial.
Scientists have previously used stellar streams to study dark matter within the Milky Way. Now, this new discovery offers the possibility of applying the same technique to better understand the amount and structure of dark matter in other galaxies.
This new star stream was found in an “ultra-diffuse galaxy”, which has extremely low luminosity and a very diffuse structure.
The researchers believe that these characteristics may have made the stellar stream easier to identify.
“Ultra-diffusive galaxies are very massive,” explained co-lead author Sarah Pearson. She stated that the galaxy needs to be massive enough to pull stars from its original star cluster.
