Triangulum II (Tri II or Laevens 2) is a

dwarf galaxy A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is ...

close to the

Milky Way Galaxy The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

. Like other dwarf spheroidal galaxies, its stellar population is very old: the galaxy was

quenched In materials science, quenching is the rapid cooling of a workpiece in water, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phas ...

before 11.5 billion years ago. It contains only 1000 stars, yet is quite massive, having a solar mass to light ratio of 3600. This is an unusually high mass for such a small galaxy. ; The distance from the centre of the Milky Way is . The luminosity is 450 times that of the Sun. This makes it one of the dimmest known galaxies. The 2D half light radius is . The galaxy was discovered in images taken by

Pan-STARRS The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...

by Benjamin P. M. Laevens in 2015. Triangulum II is a candidate for detecting

WIMP Wimp, WIMP, or Wimps may refer to: Science and technology * Weakly interacting massive particle, a hypothetical particle of dark matter * WIMP (computing), the "window, icon, menu, pointer" paradigm * WIMP (software bundle), the web stack of Wind ...

s as a source of

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...

References

{{DEFAULTSORT:Triangulum II Dwarf galaxies Triangulum Milky Way Subgroup Astronomical objects discovered in 2015