A giant diffuse tail of stars has been discovered emanating from a large, faint dwarf galaxy. A tail indicates that the galaxy has experienced recent interaction with another galaxy. This is an important clue for understanding how so-called "ultra-diffuse" galaxies are formed. Astronomers using the Subaru Telescope and the Canada-France-Hawaii Telescope found a tail of stars stretching 200,000 light-years out away from a galaxy known as F8D1. This galaxy is a member of the M81 group located 12 million light-years away on the boundary between the constellations Ursa Major and Camelopardalis. F8D1 is one of the closest examples of an "ultra-diffuse" galaxy. The origin of these enigmatic galaxies has puzzled astronomers for several decades: are they born this diffuse or does some later event cause them to puff up in size?
About the Author
