Scientists have discovered the darkest of all known galaxies, which contains 1000 ancient, small and faded stars. Dwarf galaxy Segue 1 is located close to the Milky Way and is, for the most part, a huge cloud of black cloth, diluted stars. Its mass of 3400 times greater than would be expected in the number of visible stars.
Segue 1 was discovered two years ago, ten-meter Keck II telescope in Hawaii Marla Gehoy researchers from Yale University, and Joshua Simon from the Carnegie Institution of Washington.
Additional research by Dr. Simon and his team carried out using a spectrograph to study extragalactic objects Deep Extragalactic Imaging Multi-Object Spectrograph, have shown that these stars are moving not only in relation to the Milky Way, but also in relation to each other.
If the galaxy consisted of 1000 members, with a small amount of dark matter, all the stars move with about the same speed. But as shown by data from the Keck Observatory, their speed varies greatly among themselves.
Instead of having to move at a constant speed of 209 kilometers per second relative to the Milky Way, some stars are moving at a speed of 194 kilometers per second, while the speed of the other is 224 kilometers per second. Dr. Geha explained: "It is said that Segue 1 must have much greater mass to accelerate the stars to such an extent."
It is estimated that such a velocity that can be seen on Segue 1, corresponds to the weight of 600 000 solar units.
But since Segue 1 is only 1000 stars which correspond roughly to the mass of our Sun on, almost all the rest belongs to the mass of dark matter.
One way to determine the age of stars is to analyze their chemical composition, which can be identified by its emission spectrum of the light.
Very old or primitive stars have had time to rework their light atoms such as hydrogen and helium into heavier elements such as iron and oxygen. Younger star, however, contain small amounts of heavy elements. Scientists have gathered information on the content of iron in the six stars of the galaxy Segue 1 with the Keck telescope 2, and one star from Segue 1 with the Very Large Telescope in Australia.
Dr. Simon said: "This study shows that it is one of the oldest and least developed of all known stars."
The study was published in the journal Astrophysical Journal.