Chemical abundances of 3 stars in Grus II galaxy

DOI

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 GrusII. 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 (>=20M{sun}) core-collapse supernovae has been shown to create this signature. The abundances of this small sample (three) stars suggests the chemical enrichment of GrusII could have occurred through substantial high-mass stellar evolution, and is consistent with the framework of a top-heavy initial mass function. However, with only three stars it cannot be ruled out that the abundance pattern is the result of a stochastic chemical enrichment at early times in the galaxy. The most metal-rich of the three stars also possesses a small enhancement in rapid neutron-capture (r-process) elements. The abundance pattern of the r-process elements in this star matches the scaled r-process pattern of the solar system and r-process enhanced stars in other dwarf galaxies and in the MW halo, hinting at a common origin for these elements across a range of environments. All current proposed astrophysical sites of r-process element production are associated with high- mass stars, thus the possible top-heavy initial mass function of GrusII would increase the likelihood of any of these events occurring. The time delay between the {alpha} and r-process element enrichment of the galaxy favors a neutron star merger as the origin of the r-process elements in GrusII.

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Identifier
DOI http://doi.org/10.26093/cds/vizier.18970183
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/897/183
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/897/183
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/897/183
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/897/183
Provenance
Creator 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.; Allam S.; Avila S.; Bertin E.; Brooks D.,Buckley-Geer E.; Burke D.L.; Rosell A.C.; Kind M.C.; Carretero J.,Costanzi M.; Da Costa L.N.; Desai S.; De Vicente J.; Doel P.; Eckert K.,Eifler T.F.; Everett S.; Ferrero I.; Frieman J.; Garcia-Bellido J.,Gaztanaga E.; Gerdes D.W.; Gruen D.; Gruendl R.A.; Gschwend J.,Gutierrez G.; Hinton S.R.; Hollowood D.L.; Honscheid K.; Kuropatkin N.,Maia M.A.G.; March M.; Miquel R.; Palmese A.; Paz-Chinchon F.; Plazas A.A.,Sanchez E.; Santiago B.; Scarpine V.; Serrano S.; Smith M.; Soares-Santos M.; Suchyta E.; Swanson M.E.C.; Tarle G.; Varga T.N.; Wilkinson R.
Publisher CDS
Publication Year 2021
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Galactic and extragalactic Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy