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Grus II

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Grus ll
Observation data
ConstellationGrus
Right ascension331.02
Declination-46.44
Distance179,386 ly
Group or clusterMilky Way subgroup

Grus ll is an ultra-faint dwarf galaxy (UFD) located at a distance of 55 kiloparsecs from the Milky Way in the constellation of Grus.[1]

It has a higher than expected ratio of [Mg/Ca] than other metal poor stars in ultra-diffuse galaxies. The chemical enrichment of Grus ll is from the stellar nucleosynthesis of core collapse supernovas from high mass stars over 20 solar masses and the merging of neutron stars. The stars within Grus ll may also possess a small enhancement of rapid neutron capture (r-process) elements.[2]

Reference

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  1. ^ Martínez-Vázquez, C. E.; Vivas, A. K.; Gurevich, M.; Walker, A. R.; McCarthy, M.; Pace, A. B.; Stringer, K. M.; Santiago, B.; Hounsell, R.; Macri, L.; Li, T. S.; Bechtol, K.; Riley, A. H.; Kim, A. G.; Simon, J. D. (December 2019). "Search for RR Lyrae stars in DES ultrafaint systems: Grus I, Kim 2, Phoenix II, and Grus II". Monthly Notices of the Royal Astronomical Society. 490 (2): 2183–2199. arXiv:1909.06308. Bibcode:2019MNRAS.490.2183M. doi:10.1093/mnras/stz2609. ISSN 0035-8711.
  2. ^ Hansen, T. T.; Marshall, J. L.; Simon, J. D.; Li, T. S.; Bernstein, R. A.; Pace, A. B.; Ferguson, P.; Nagasawa, D. Q.; Kuehn, K.; Carollo, D.; Geha, M.; James, D.; Walker, A.; Diehl, H. T.; Aguena, M. (July 2020). "Chemical Analysis of the Ultrafaint Dwarf Galaxy Grus II. Signature of High-mass Stellar Nucleosynthesis". The Astrophysical Journal. 897 (2): 183. arXiv:2005.10767. Bibcode:2020ApJ...897..183H. doi:10.3847/1538-4357/ab9643. ISSN 0004-637X.