Metal-poor stars observed with the Magellan Telescope – IV. Neutron-capture element signatures in 27 main-sequence stars

Metal-poor stars observed with the Magellan Telescope – IV. Neutron-capture element signatures in 27 main-sequence stars

ABSTRACT We present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analysed for the first time. The sample spans a range in [Fe/H] from −2.5 to −3.6, with 44 per cent having [Fe/H]

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Veröffentlicht in:Monthly notices of the Royal Astronomical Society 2024-02, Vol.528 (2), p.2912-2929
Hauptverfasser: Mardini, Mohammad K, Frebel, Anna, Betre, Leyatt, Jacobson, Heather, Norris, John E, Christlieb, Norbert
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container_issue 2
container_start_page 2912
container_title Monthly notices of the Royal Astronomical Society
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creator Mardini, Mohammad K
Frebel, Anna
Betre, Leyatt
Jacobson, Heather
Norris, John E
Christlieb, Norbert
description ABSTRACT We present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analysed for the first time. The sample spans a range in [Fe/H] from −2.5 to −3.6, with 44 per cent having [Fe/H]
doi_str_mv 10.1093/mnras/stad3925
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This broadly indicates chemically homogeneous gas at the earliest times. We used the [Sr/Ba] versus [Ba/Fe] diagram to classify metal-poor stars into five populations based on their observed ratios. We find HE 0232 − 3755 to be a likely main r-process star, and HE 2214 − 6127 and HE 2332 − 3039 to be limited-r stars. CS30302-145, HE 2045 − 5057, and CD −24°17504 plausibly originated in long-disrupted early dwarf galaxies. We also find that the derived [Sr/H] and [Ba/H] values for CD −24°17504 are not inconsistent with the predicted yields of the s-process in massive rotating low-metallicity stars models. Further theoretical explorations will be helpful to better understand the earliest mechanisms and time scales of heavy element production for comparison with these and other observational abundance data. Finally, we investigate the orbital histories of our stars. 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title Metal-poor stars observed with the Magellan Telescope – IV. Neutron-capture element signatures in 27 main-sequence stars
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