APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy

Sten Hasselquist, Matthew Shetrone, Verne Smith, Jon Holtzman, Andrew McWilliam, J. G. Fernández-Trincado, Timothy C. Beers, Steven R. Majewski, David L. Nidever, Baitian Tang, Patricia B. Tissera, Emma Fernández Alvar, Carlos Allende Prieto, Andres Almeida, Borja Anguiano, Giuseppina Battaglia, Leticia Carigi, Gloria Delgado Inglada, Peter Frinchaboy, D. A. Garcia-HernándezDoug Geisler, Dante Minniti, Vinicius M. Placco, Mathias Schultheis, Jennifer Sobeck, Sandro Villanova

Resultado de la investigación: Contribución a una revistaArtículo

31 Citas (Scopus)

Resumen

The Apache Point Observatory Galactic Evolution Experiment provides the opportunity of measuring elemental abundances for C, N, O, Na, Mg, Al, Si, P, K, Ca, V, Cr, Mn, Fe, Co, and Ni in vast numbers of stars. We analyze thechemical-abundance patterns of these elements for 158 red giant stars belonging to the Sagittarius dwarf galaxy (Sgr). This is the largest sample of Sgr stars with detailed chemical abundances, and it is the first time that C, N, P, K, V, Cr, Co, and Ni have been studied at high resolution in this galaxy. We find that the Sgr stars with [Fe/H] ≈ -0.8 are deficient in all elemental abundance ratios (expressed as [X/Fe]) relative to the Milky Way, suggesting that the Sgr stars observed today were formed from gas that was less enriched by Type II SNe than stars formed in the Milky Way. By examining the relative deficiencies of the hydrostatic (O, Na, Mg, and Al) and explosive (Si, P, K, and Mn) elements, our analysis supports the argument that previous generations of Sgr stars were formed with a top-light initial mass function, one lacking the most massive stars that would normally pollute the interstellar medium with the hydrostatic elements. We use a simple chemical-evolution model, flexCE, to further support our claim and conclude that recent stellar generations of Fornax and the Large Magellanic Cloud could also have formed according to a top-light initial mass function.

Idioma originalInglés
Número de artículo162
PublicaciónAstrophysical Journal
Volumen845
N.º2
DOI
EstadoPublicada - 20 ago 2017

Áreas temáticas de ASJC Scopus

  • Astronomía y astrofísica
  • Ciencias planetarias y espacial

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    Hasselquist, S., Shetrone, M., Smith, V., Holtzman, J., McWilliam, A., Fernández-Trincado, J. G., Beers, T. C., Majewski, S. R., Nidever, D. L., Tang, B., Tissera, P. B., Alvar, E. F., Allende Prieto, C., Almeida, A., Anguiano, B., Battaglia, G., Carigi, L., Delgado Inglada, G., Frinchaboy, P., ... Villanova, S. (2017). APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy. Astrophysical Journal, 845(2), [162]. https://doi.org/10.3847/1538-4357/aa7ddc