The collection of stars at the edge of the area was analyzed and deemed that they were not part of the cluster contained in the Milky Way, but a small galaxy which is nearly 30 million light-years away. After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster - which is part of the Milky Way - but rather they are millions of light-years more distant.
Bedin 1 is classified as a "dwarf spheroidal galaxy" because of its relatively small size.
Nestled behind the cluster's crowded star population, a dwarf galaxy was spotted for the first time, NASA said.
In the 1990s, the famous Hubble Deep Field image led NASA to believe there were about 200 billion galaxies in the universe.
Reference: These results will be published online January 31, 2019, in Monthly Notices of the Royal Astronomical Society: Letters [https://academic.oup.com/mnrasl]. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way. Its stars are also old, like really old, revealing that the galaxy is as ancient as the universe itself - approximately 13 billion years old. These faint stars were being studied so that scientists could better gauge how old the cluster was as a whole, but that's when they noticed what appeared to be a galaxy that had yet to be documented. And that's what makes Bedin 1 so interesting for astronomers. The Hubble Space Telescope team initially planned to determine the age of a globular cluster by measuring its faintest stars, but ended up stumbling upon a small galaxy while doing so. The researchers suspect that Bedin-1 is the most isolated galaxy ever discovered. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744.
NASA's Hubble Space Telescope has been peering into the unknown and infinite universe for almost 30 years.