Meet the Milky Way's New Neighbor, KKs3

Meet the Milky Way's new neighbor, KKs3, a dwarf galaxy located almost seven million light-years away, new research describes.

Kks3 is a "dwarf spheroidal" - or dSph galaxy - unlike our own Milky Way, and despite its isolated existence, astronomers hope this discovery can shed some light on the history of galaxy formation.

"Finding objects like KKs3 is painstaking work, even with observatories like the Hubble Space Telescope. But with persistence, we're slowly building up a map of our local neighborhood, which turns out to be less empty than we thought," Dimitry Makarov, part of the Russian-American team that found the dwarf galaxy, said in a statement. "It may be that are a huge number of dwarf spheroidal galaxies out there, something that would have profound consequences for our ideas about the evolution of the cosmos."

The Milky Way is part of a cluster of more than 50 galaxies that make up the "Local Group," a collection that includes the famous Andromeda galaxy and many other far smaller objects. KKs3 is just one of these many galaxies, located in the southern sky in the direction of the constellation of Hydrus. It lacks features found in our own galaxy, like the Milky Way's characteristic spiral arms, as well as gas and dust needed for new stars to form. Its stars also have only one ten-thousandth of the mass of the Milky Way.

The team, led by Professor Igor Karachentsev of the Special Astrophysical Observatory in Karachai-Cherkessia, Russia, which found KKs3 in August 2014, suspect that isolated objects like this orphan dwarf galaxy formed differently in comparison to other galaxies, For example, they may have had an early burst of star formation that used up all the available gas resources, which is why KKs3 doesn't contain any gas or dust.

Finding dSph objects is difficult, even with the advanced Hubble Space Telescope - the only other known isolated spheroidal dwarf is KKR 25, found by the same team in 1999. The lack of hydrogen gas clouds in nebulae makes them harder spot. Nevertheless, scientists are trying to locate more dSph galaxies by their individual stars alone, a task that may become easier once more advanced instruments like the European Extremely Large Telescope (E-ELT) become operational.

The results were published in the journal Monthly Notices of the Royal Astronomical Society.

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