Sextans Dwarf Spheroidal

Sextans Dwarf Spheroidal
Observation data (J2000 epoch)
Constellation	Sextans
Right ascension	10^h 13^m 02.9^s[1]
Declination	−01° 36′ 53″[1]
Redshift	224 ± 2 km/s[1]
Distance	290 ± 30 kly (90 ± 10 kpc)[2][3]
Apparent magnitude (V)	10.4[1]
Characteristics
Type	dSph[1]
Apparent size (V)	30.0′ × 12.0′[1]
Notable features	satellite galaxy of the Milky Way
Other designations
Sextans I,[1] LEDA 88608[1]

The Sextans Dwarf Spheroidal is a dwarf spheroidal galaxy that was discovered in 1990 by Mike Irwin as the 8th satellite of the Milky Way,^[4] located in the constellation of Sextans. It is also an elliptical galaxy, and displays a redshift because it is receding from the Sun at 224 km/s (72 km/s from the Galaxy). The distance to the galaxy is 320,000 light-years and the diameter is 8,400 light-years along its major axis.^[5]

Like other dwarf spheroidal galaxies, the Sextans Dwarf's population consists of old, metal-poor stars: one study found that the majority of stars have a metallicity between [Fe/H] = −3.2 and −1.4. An analysis of several stars found them to also be deficient in barium, except for one star.^[6]

References

1. "NASA/IPAC Extragalactic Database". Results for Sextans Dwarf. Retrieved 2006-11-29.
2. I. D. Karachentsev; V. E. Karachentseva; W. K. Hutchmeier; D. I. Makarov (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
3. Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics. 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6. S2CID 120973010.
4. M. J. Irwin; P. S. Bunclark; M. T. Bridgeland; R. G. McMahon (1990). "A new satellite galaxy of the Milky Way in the constellation of Sextans". Monthly Notices of the Royal Astronomical Society. 244: 16–19. Bibcode:1990MNRAS.244P..16I.
5. Hartmut Frommert. "Sextans Dwarf". SEDS. Retrieved 2015-03-21.
6. Mashonkina, L.; Pakhomov, Yu V.; Sitnova, T.; Jablonka, P.; Yakovleva, S. A.; Belyaev, A. K. (2022). "The formation of the Milky Way halo and its dwarf satellites: A NLTE–1D abundance analysis. V. The Sextans galaxy". Monthly Notices of the Royal Astronomical Society. 509 (3): 3626–3642. arXiv:2110.09402. doi:10.1093/mnras/stab3189.