The finding is reported in the journal "Monthly Notices of the Royal Astronomical Society: Letters".
Astronomers using the NASA Hubble Space Telescope and the European Space Agency (ESA) to study some of the oldest and weakest stars in the globular cluster NGC 6752 & # 39; They made an unexpected discovery: a dwarf galaxy at 30 million light years of almost the same age as the Universe itself.
The aim of these scientists' observations was to use the stars of the cluster NGC 6752 & # 39; to measure the age of the globular clump, but in the process they made an unexpected discovery.
On the outer edges of the area observed with the Hubble ACS camera, it seemed a compact collection of stars. After a careful analysis of their brightness and temperature, astronomers concluded that these stars they did not belong to the cluster, which is part of the Milky Way, but they were millions of light-years away.
The newly discovered cosmic neighbor, which was dubbed "Bedin 1" by astronomers, is a galaxy of modest and elongated size. It measures only about 3,000 light-years in its maximum extent, a fraction of the size of the Milky Way. Not only is it small, it is also incredibly weak. These properties led astronomers to classify it as a spheroidal dwarf galaxy.
& # 39; LIVING FOSSIL & # 39;
Spheroidal dwarf galaxies are defined by their small size, low luminosity, lack of dust and old star populations.. It is known that there are 36 galaxies of this type in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.
While spheroidal dwarf galaxies they are not uncommon, & # 39; Bedin 1 & # 39; has some notable features. Not only is it one of the few dwarf spheroids that has a well-established distance, but also It is extremely isolated. They are about 30 million light years from the Milky Way and 2 million light-years from the nearest large plausible galaxy, & # 39; NGC 6744 & # 39; This does what possibly the most isolated small dwarf galaxy discovered to date.
From the properties of their stars, astronomers could infer that the galaxy has about 13,000 million years ago, almost as old as the Universe itself. Due to its insulation, which resulted in almost no interaction with other galaxies, and at its age, & # 39; Bedin 1 & # 39; is the astronomical equivalent of a living fossil & # 39; of the primitive Universe.
The discovery of Bedin 1 & # 39; was a truly fortuitous find. Very few Hubble images allow objects to appear so weak and cover only a small area of the sky. O Future telescopes with a large field of view, such as the WFIRST telescope, will have cameras that cover a much larger area of the sky. and you can find many more of these galactic neighbors.