This discovery is published in the magazine "Monthly Announcements of the Royal Astronomical Society: Letters".
Astronomers use the Hubble Space Telescope from NASA and the European Space Agency (ESA) to study some of the oldest and weakest stars in the globular cluster "NGC 6752" They made an unexpected discovery: a dwarf galaxy of 30 million light years away from almost the same age as the Universe itself.
The purpose of observing these scientists was to use the NGC 6752 cluster stars to measure the age of the cluster, but in the process they made an unexpected discovery.
On the outer edges of the area spotted with the camera of Hubble ACS, it looked a compact collection of stars. After a careful analysis of its brightness and temperature, astronomers have concluded that these stars they did not belong to the cluster, which is part of the Milky Way, but were far from millions of light years old.
Newly discovered cosmic neighbor, which is called "Bedin 1" by astronomers, is a galaxies of modest and elongated size. It measures just about 3,000 light-years to its fullest, part of the Milky Way's size. Not only is it small, but it is also incredibly weak. These properties have led astronomers to classify it as a spheroid dwarf galaxy.
Dwarf spheroidal galaxies are defined by their small size, low gloss, dust deficiency and old star populations. It is already known that in the Local Galaxies group there are 36 galaxies of this type, of which 22 are satellite galaxies of the Milky Way.
While the dwarf spheroidal galaxies they are not uncommon, Bedin 1 & # 39; has some outstanding features. Not only is it one of the few dwarf spheroids that have a well-established distance, but also It is extremely isolated. It is about 30 million light-years from the Milky Way and 2 million light-years from the host of the nearest highly reliable galaxy, "NGC 6744". This is what he does perhaps the most isolated small dwarf galaxy discovered so far.
From the properties of their stars, astronomers can conclude that the galaxy has about 13,000 million years ago, almost as old as the Universe itself. Because of the isolation, resulting in almost no interaction with other galaxies and its age, "Bedin 1" is the astronomical equivalent of the "living fossil" of the primitive Universe.
The discovery of "Bedin 1" was indeed a coincidence. Very few images from Hubble allow objects to appear so weakly, and cover only a small area of the sky. On future telescopes with a large field of vision, such as the WFIRST telescope, will have cameras that cover a much larger area than the sky and you can find a lot more of these galactic neighbors.