Hubble Telescope spots a dwarf 'living fossil' galaxy in the backyard of Milky Way

Bedin I is 13 billion years old and could be the most isolated dwarf galaxy found to date

Astronomers have accidentally discovered a dwarf galaxy in the backyard of the Milky Way.

Called Bedin I, the galaxy lies just 30 million light-years away from Earth and was found when astronomers were searching for white dwarf stars in a specific star cluster in the Universe.

The galaxy was nicknamed Bedin I after research team leader LR Bedin of the INAF-Osservatorio Astronomico di Padova, an observatory in Italy.

It was discovered when astronomers were looking for white dwarf stars in the globular star cluster NGC 6752 using the Hubble Space Telescope. NGC 6752 is located 13,000 light-years away in Milky Way's halo.

When the team captured photographs of NGC 6752, they noticed a small set of stars on the edge of the area they were observing. Upon further investigation, astronomers found that those stars were not part of the NGC 6752 cluster, but were actually millions of light-years away from it.

Further observations helped astronomers to discover the dwarf spheroidal galaxy which was found to be sitting behind the crowded stellar population of NGC 6752. The galaxy is much smaller in size than the Milky Way, measuring just 3,000 light-years at its furthest extent.

In comparison, the spiral disk of the Milky Way has a diameter of 100,000 light-years.

Bedin I is about one thousand times dimmer than our galaxy, and is believed not to have been observed before. According to astronomers, it is too faint and too close to the core of NGC 6752 for detection in earlier surveys.

Spheroidal dwarf galaxies are not uncommon in the universe. Astronomers have discovered more than 20 such galaxies, which are satellite galaxies of the Milky Way.

But Bedin I is unique in many ways. It is two million light-years away from NCG 6744, the nearest big galaxy that could possibly be its host. Moreover, it is 13 billion years old and could be the most isolated dwarf galaxy found to date.

Because of its age and isolation, this galaxy is the astronomical equivalent of a living fossil from the early Universe, astronomers think, meaning that further investigation could help uncover clues about how the Universe was formed.

The findings of the study are published in the journal Monthly Notices of the Royal Astronomical Society: Letters.