Browsing by Author "Yong, D."

Now showing items 1-5 of 5

    • Constraining Nucleosynthesis in Two CEMP Progenitors Using Fluorine 

      Mura-Guzmán, A.; Yong, D.; Abate, C.; Karakas, A.; Kobayashi, C.; Oh, H.; Chun, S.; Mace, G.; . (2020-11-01)
      We present new fluorine abundance estimations in two carbon enhanced metal-poor (CEMP) stars, HE 1429-0551 and HE 1305+0007. HE 1429-0551 is also enriched in slow neutron-capture process (s-process) elements, a CEMP-s, and ...

    • Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way 

      Howes, L. M.; Casey, A. R.; Asplund, M.; Keller, S. C.; Yong, D.; Nataf, D. M.; Poleski, R.; Lind, K.; Kobayashi, C.; Owen, C. I.; Ness, M.; Bessell, M. S.; Costa, G. S. Da; Schmidt, B. P.; Tisserand, P.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Pietrzyński, G.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P.; Skowron, J.; Kozłowski, S.; Mróz, P. (2015-11-26)
      The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than ...

    • High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1 

      Yong, D.; Costa, G. S. Da; Bessell, M. S.; Chiti, A.; Frebel, A.; Gao, X.; Lind, K.; Mackey, A. D.; Marino, A. F.; Murphy, S. J.; Nordlander, T.; Asplund, M.; Casey, A. R.; Kobayashi, C.; Norris, J. E.; Schmidt, B. P. (2021-11-01)
      We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning -4.1 < [Fe/H] < -2.1. The targets were selected from the SkyMapper survey and include 90 objects with [Fe/H] ≤ -3 of ...

    • R-Process elements from magnetorotational hypernovae 

      Yong, D.; Kobayashi, C.; Costa, G. S. Da; Bessell, M. S.; Chiti, A.; Frebel, A.; Lind, K.; Mackey, A. D.; Nordlander, T.; Asplund, M.; Casey, A. R.; Marino, A. F.; Murphy, S. J.; Schmidt, B. P. (2021-07-08)
      Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis 1–3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element ...

    • Sc and neutron-capture abundances in Galactic low- and high-alpha field halo stars 

      Fishlock, C. K.; Yong, D.; Karakas, A. I.; Alves-Brito, A.; Melendez, J.; Nissen, P. E.; Kobayashi, C.; Casey, A. R. (2017-05-01)
      We determine relative abundance ratios for the neutron-capture elements Zr, La, Ce, Nd and Eu for a sample of 27 Galactic dwarf stars with −1.5 < [Fe/H] < −0.8. We also measure the iron-peak element Sc. These stars separate ...