Triangulum II explained

Triangulum II
Epoch:	J2000
Dec:	+
Dist Ly:	30+/-
Mass Light Ratio:	3600 (V)
Size V:	3.9′
Age:	13 Ga
Constellation Name:	Triangulum
Names:	Triangulum II, Tri II, Laevens 2, Lae 2

Triangulum II (Tri II or Laevens 2) is a dwarf galaxy close to the Milky Way Galaxy. Like other dwarf spheroidal galaxies, its stellar population is very old: the galaxy was quenched before 11.5 billion years ago.^[1] 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.^[2]

The distance from the centre of the Milky Way is 26kpc. The luminosity is 450 times that of the Sun.^[3] This makes it one of the dimmest known galaxies.^[3] The 2D half light radius is 34pc. The galaxy was discovered in images taken by Pan-STARRS by Benjamin P. M. Laevens in 2015.^{[4] [3]}

Triangulum II is a candidate for detecting WIMPs as a source of dark matter.^[2]

Notes and References

1. 10.3847/2041-8213/ac2aa3. Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?. 2021. Sacchi. Elena. Richstein. Hannah. Kallivayalil. Nitya. Van Der Marel. Roeland. Libralato. Mattia. Zivick. Paul. Besla. Gurtina. Brown. Thomas M.. Choi. Yumi. Deason. Alis. Fritz. Tobias. Geha. Marla. Marla Geha . Guhathakurta. Puragra. Jeon. Myoungwon. Kirby. Evan. Majewski. Steven R.. Patel. Ekta. Simon. Joshua D.. Tony Sohn. Sangmo. Tollerud. Erik. Wetzel. Andrew. The Astrophysical Journal Letters. 920. 1. L19. 2108.04271. 2021ApJ...920L..19S. 236965965 . free .
2. Web site: Dajose. Lori . Dark matter dominates in nearby dwarf galaxy . 19 November 2015 . 18 November 2015 . Phys.org .

   Web site: . Dark Matter Dominates in Nearby Dwarf Galaxy . Lori Dajose . November 18, 2015 . December 16, 2015 .

3. Kirby. Evan N.. Cohen. Judith G.. Judith Gamora Cohen. Simon. Joshua D.. Guhathakurta. Puragra. Triangulum II: Possibly a Very Dense Ultra-Faint Dwarf Galaxy . The Astrophysical Journal . 16 November 2015 . 814 . 1 . L7 . 10.1088/2041-8205/814/1/L7 . 2015ApJ...814L...7K . 1510.03856 . 13600560 .
4. Laevens. Benjamin P. M.. Martin. Nicolas F.. Ibata. Rodrigo A.. Rix. Hans-Walter. Bernard. Edouard J.. Bell. Eric F.. Sesar. Branimir. Ferguson. Annette M. N.. Schlafly. Edward F.. Slater. Colin T.. Burgett. William S.. Chambers. Kenneth C.. Flewelling. Heather. Hodapp. Klaus A.. Kaiser. Nicholas. Kudritzki. Rolf-Peter. Lupton. Robert H.. Magnier. Eugene A.. Metcalfe. Nigel. Morgan. Jeffrey S.. Price. Paul A.. Tonry. John L.. Wainscoat. Richard J.. Waters. Christopher. 10. A New Faint Milky Way Satellite Discovered in the PAN-STARRS1 3π Survey . The Astrophysical Journal . 31 March 2015 . 802 . 2 . L18 . 10.1088/2041-8205/802/2/L18 . 2015ApJ...802L..18L . 1503.05554 . 54179272 .