Astronomers Discover an Ultra-Faint Satellite of the Milky Way

An international team of astronomers has discovered a dwarf galaxy Pegasus IV. It is a previously unknown satellite of the Milky Way.

Pegasus IV is classified as an ultra-faint galaxy. Such objects are characterized by extremely low brightness but are rich in mysterious dark matter. Ultra-faint galaxies are thought to be very ancient objects, formed shortly after the Big Bang.

Astronomers estimate that Pegasus IV is about 294,000 light-years from the Sun. It moves in a retrograde orbit around the Milky Way. The galaxy's radius is 135 light-years, and the total mass of the stellar population is estimated at 4,400 solar masses. As for the age of Pegasus IV, it is comparable with the age of our Galaxy and is equal to 12.5 billion years.

According to scientists, there could be many more such ultra-faint galaxies in the vicinity of the Milky Way.