Akademska digitalna zbirka SLovenije - logo
E-viri
Celotno besedilo
Recenzirano Odprti dostop
  • A Perspective on the Milky ...
    Sales-Silva, J. V.; Cunha, K.; Smith, V. V.; Daflon, S.; Souto, D.; Guerço, R.; Queiroz, A.; Chiappini, C.; Hayes, C. R.; Masseron, T.; Hasselquist, Sten; Horta, D.; Prantzos, N.; Zoccali, M.; Allende Prieto, C.; Barbuy, B.; Beaton, R.; Bizyaev, D.; Fernández-Trincado, J. G.; Frinchaboy, P. M.; Holtzman, J. A.; Johnson, J. A.; Jönsson, Henrik; Majewski, S. R.; Minniti, D.; Nidever, D. L.; Schiavon, R. P.; Schultheis, M.; Sobeck, J.; Stringfellow, G. S.; Zasowski, G.

    The Astrophysical journal, 04/2024, Letnik: 965, Številka: 2
    Journal Article

    Abstract This study probes the chemical abundances of the neutron-capture elements cerium and neodymium in the inner Milky Way from an analysis of a sample of ∼2000 stars in the Galactic bulge bar spatially contained within ∣ X Gal ∣ < 5 kpc, ∣ Y Gal ∣ < 3.5 kpc, and ∣ Z Gal ∣ < 1 kpc, and spanning metallicities between −2.0 ≲ Fe/H ≲ +0.5. We classify the sample stars into low- or high-Mg/Fe populations and find that, in general, values of Ce/Fe and Nd/Fe increase as the metallicity decreases for the low- and high-Mg/Fe populations. Ce abundances show a more complex variation across the metallicity range of our bulge-bar sample when compared to Nd, with the r -process dominating the production of neutron-capture elements in the high-Mg/Fe population (Ce/Nd < 0.0). We find a spatial chemical dependence of Ce and Nd abundances for our sample of bulge-bar stars, with low- and high-Mg/Fe populations displaying a distinct abundance distribution. In the region close to the center of the MW, the low-Mg/Fe population is dominated by stars with low Ce/Fe, Ce/Mg, Nd/Mg, Nd/Fe, and Ce/Nd ratios. The low Ce/Nd ratio indicates a significant contribution in this central region from r -process yields for the low-Mg/Fe population. The chemical pattern of the most metal-poor stars in our sample suggests an early chemical enrichment of the bulge dominated by yields from core-collapse supernovae and r -process astrophysical sites, such as magnetorotational supernovae.