Triangulum II

Triangulum II
Triangulum II
Observation data (J2000 epoch)
Constellation	Triangulum
Right ascension	02h 13m 17.4s
Declination	+36° 10′ 42.4″
Distance	97.8 ± 6.5 kly (30 ± 2 kpc)
Characteristics
Mass/Light ratio	3600 (V) M☉/L☉
Apparent size (V)	3.9′
Other designations
	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.^[2] It contains only 1000 stars, yet is quite massive, having a solar mass to light ratio of 3600.^[3] This is an unusually high mass for such a small galaxy.^[4]

The distance from the centre of the Milky Way is 26 kpc (85 kly). 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 34 pc (110 ly). The galaxy was discovered in images taken by Pan-STARRS by Benjamin P. M. Laevens in 2015.^[1]^[3]

Triangulum II is a candidate for detecting WIMPs as a source of dark matter.^[4]

References

^ ^a ^b ^c ^d ^e ^f 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.; et al. (31 March 2015). "A New Faint Milky Way Satellite Discovered in the PAN-STARRS1 3π Survey" (PDF). The Astrophysical Journal. 802 (2): L18. arXiv:1503.05554. Bibcode:2015ApJ...802L..18L. doi:10.1088/2041-8205/802/2/L18. S2CID 54179272.
^ 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; Guhathakurta, Puragra; Jeon, Myoungwon; Kirby, Evan; Majewski, Steven R.; Patel, Ekta; Simon, Joshua D.; Tony Sohn, Sangmo; Tollerud, Erik; Wetzel, Andrew (2021). "Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?". The Astrophysical Journal Letters. 920 (1): L19. arXiv:2108.04271. Bibcode:2021ApJ...920L..19S. doi:10.3847/2041-8213/ac2aa3. S2CID 236965965.
^ ^a ^b ^c ^d Kirby, Evan N.; Cohen, Judith G.; Simon, Joshua D.; Guhathakurta, Puragra (16 November 2015). "Triangulum II: Possibly a Very Dense Ultra-Faint Dwarf Galaxy". The Astrophysical Journal. 814 (1): L7. arXiv:1510.03856. Bibcode:2015ApJ...814L...7K. doi:10.1088/2041-8205/814/1/L7. S2CID 13600560.
^ ^a ^b Dajose, Lori (18 November 2015). "Dark matter dominates in nearby dwarf galaxy". Phys.org. Retrieved 19 November 2015.; Lori Dajose (November 18, 2015). "Dark Matter Dominates in Nearby Dwarf Galaxy". Caltech. Retrieved December 16, 2015.

[Laev-1] ^ ^a ^b ^c ^d ^e ^f 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.; et al. (31 March 2015). "A New Faint Milky Way Satellite Discovered in the PAN-STARRS1 3π Survey" (PDF). The Astrophysical Journal. 802 (2): L18. arXiv:1503.05554. Bibcode:2015ApJ...802L..18L. doi:10.1088/2041-8205/802/2/L18. S2CID 54179272.

[Sacchi-2] 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; Guhathakurta, Puragra; Jeon, Myoungwon; Kirby, Evan; Majewski, Steven R.; Patel, Ekta; Simon, Joshua D.; Tony Sohn, Sangmo; Tollerud, Erik; Wetzel, Andrew (2021). "Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?". The Astrophysical Journal Letters. 920 (1): L19. arXiv:2108.04271. Bibcode:2021ApJ...920L..19S. doi:10.3847/2041-8213/ac2aa3. S2CID 236965965.

[Kirb-3] Kirby, Evan N.; Cohen, Judith G.; Simon, Joshua D.; Guhathakurta, Puragra (16 November 2015). "Triangulum II: Possibly a Very Dense Ultra-Faint Dwarf Galaxy". The Astrophysical Journal. 814 (1): L7. arXiv:1510.03856. Bibcode:2015ApJ...814L...7K. doi:10.1088/2041-8205/814/1/L7. S2CID 13600560.

[lori-4] Dajose, Lori (18 November 2015). "Dark matter dominates in nearby dwarf galaxy". Phys.org. Retrieved 19 November 2015.; Lori Dajose (November 18, 2015). "Dark Matter Dominates in Nearby Dwarf Galaxy". Caltech. Retrieved December 16, 2015.

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