Chemical Analysis of the Ultrafaint Dwarf Galaxy Grus II. Signature of High-mass Stellar Nucleosynthesis

  title={Chemical Analysis of the Ultrafaint Dwarf Galaxy Grus II. Signature of High-mass Stellar Nucleosynthesis},
  author={Terese T. Hansen and Jennifer L. Marshall and Joshua D. Simon and T. S. Li and R. A. Bernstein and Andrew B. Pace and P. S. Ferguson and Daniel Q. Nagasawa and Kyler W. Kuehn and Daniela Carollo and Marla C. Geha and David J. James and Alistair R. Walker and H. Thomas Diehl and Michel Aguena and Sahar Allam and Santiago {\'A}vila and Emmanuel Bertin and David Brooks and Elizabeth Buckley-Geer and David L. Burke and Aurelio Carnero Rosell and Matias Carrasco Kind and Jorge Carretero and Matteo Costanzi and L. N. da Costa and Shantanu Desai and Juan de Vicente and Peter Doel and Kathleen D. Eckert and T. F. Eifler and S. Everett and I. Ferrero and Joshua A. Frieman and Juan Garc{\'i}a-Bellido and Enrique Gazta{\~n}aga and David W. Gerdes and Daniel Gruen and Robert A. Gruendl and Julia Gschwend and Gaston R. Guti{\'e}rrez and Samuel R. Hinton and Devon L. Hollowood and Klaus Honscheid and Nikolay Kuropatkin and Marcio A. G. Maia and M March and Ramon Miquel and Antonella Palmese and Francisco Paz-Chinch{\'o}n and Andreas Alejandro Plazas and Eusebio S{\'a}nchez and Bas{\'i}lio Xavier Santiago and Victor E. Scarpine and Santiago Serrano and M. Smith and Marcelle Soares-Santos and Eric Suchyta and Mollye E. C. Swanson and Gregory G. Tarl{\'e} and T. N. Varga and R. D. Wilkinson},
  journal={The Astrophysical Journal},
We present a detailed abundance analysis of the three brightest member stars at the top of the giant branch of the ultrafaint dwarf (UFD) galaxy Grus II. All stars exhibit a higher than expected [Mg/Ca] ratio compared to metal-poor stars in other UFD galaxies and in the Milky Way (MW) halo. Nucleosynthesis in high-mass ( 20 M⊙) core-collapse supernovae has been shown to create this signature. The abundances of this small sample (three) stars suggests the chemical enrichment of Grus II could… 

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