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| Eridanus II Dwarf Galaxy | |
|---|---|
| Observation data (J2000 epoch) | |
| Constellation | Eridanus |
| Right ascension | 03h 44m 20.1s (Crnojević et al., 2016) |
| Declination | −43° 32′ 01.7″ (Crnojević et al., 2016) |
| Distance | 1,207 ± 29 kly (370 ± 9 kpc)[1] |
| Characteristics | |
| Type | dSph[2] |
| Apparent size (V) | 4.6 arcmin (Crnojević et al., 2016) |
| Notable features | contains a centrally-located globular cluster |
| Other designations | |
| Eridanus 2 (Koposov et al. 2015), DES J0344.3-4331 (Bechtol et al., 2015). | |
The Eridanus II Dwarf is a low-surface brightness dwarf galaxy in the constellation Eridanus. Eridanus II was independently discovered by two groups in 2015, using data from the Dark Energy Survey (Bechtol et al., 2015; Koposov et al. 2015). This galaxy is probably a distant satellite of the Milky Way (Li et al., 2016). Eridanus II contains a centrally located globular cluster; and is the smallest, least luminous galaxy known to contain a globular cluster. Crnojević et al., 2016. Eridanus II is significant, in a general sense, because the widely accepted Lambda CDM cosmology predicts the existence of many more dwarf galaxies than have yet been observed. The search for just such bodies was one of the motivations for the ongoing Dark Energy Survey observations. Eridanus II has special significance because of its apparently stable globular cluster. The stability of this cluster, near the center of such a small, diffuse, galaxy places constraints on the nature of dark matter (Brandt 2016; Li et al., 2016).
- ^ Martínez-Vázquez, C. E.; Monelli, M.; Cassisi, S.; Taibi, S.; Gallart, C.; Vivas, A. K.; Walker, A. R.; Martín-Ravelo, P.; Zenteno, A.; Battaglia, G.; Bono, G.; Calamida, A.; Carollo, D.; Cicuéndez, L.; Fiorentino, G.; Marconi, M.; Salvadori, S.; Balbinot, E.; Bernard, E. J.; Dall'Ora, M.; Stetson, P. B. (2021). "Variable stars in Local Group galaxies – V. The fast and early evolution of the low-mass Eridanus II d SPH galaxy". Monthly Notices of the Royal Astronomical Society. 508: 1064–1083. arXiv:2109.01177. doi:10.1093/mnras/stab2493.
- ^ Eridanus II is usually grouped with other dwarf spheroidal galaxies in the literature, but this characterization is not yet certain. One group has classified Eridanus II as a probable or candidate dSph (Albert et al., 2017: 4, Table 1 note). Pawlowski et al. (2015: 2, Table 1) simply refer to it as an "unclassified dwarf" galaxy.