Constraining Nucleosynthesis in Two CEMP Progenitors Using Fluorine
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 HE 1305+0007 is enhanced in both, slow and rapid neutron-capture process elements, a CEMP-s/r. The F abundances estimates are derived from the vibration-rotation transition of the HF molecule at 23358.6 Š using high-resolution infrared spectra obtained with the Immersion Grating Infrared Spectrometer (IGRINS) at the 4-m class Lowell Discovery Telescope. Our results include an F abundance measurement in HE 1429-0551 of A(F) = +3.93 ([F/Fe] = +1.90) at [Fe/H] = -2.53, and an F upper limit in HE 1305+0007 of A(F) < +3.28 ([F/Fe] < +1.00) at [Fe/H] = -2.28. Our new derived F abundance in HE 1429-0551 makes this object the most metal-poor star where F has been detected. We carefully compare these results with literature values and state-of-the-art CEMP-s model predictions including detailed asymptotic giant branch (AGB) nucleosynthesis and binary evolution. The modelled fluorine abundance for HE 1429-0551 is within reasonable agreement with our observed abundance, although is slightly higher than our observed value. For HE 1429-0551, our findings support the scenario via mass transfer by a primary companion during its thermally pulsing phase. Our estimated upper limit in HE 1305+0007, along with data from the literature, shows large discrepancies compared with AGB models. The discrepancy is principally due to the simultaneous s- and r-process element enhancements which the model struggles to reproduce.
Item Type | Article |
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Additional information | © 2020 The Author(s). The version of record [Aldo Mura-Guzmán, D Yong, C Abate, A Karakas, C Kobayashi, H Oh, S-H Chun, G Mace, Constraining nucleosynthesis in two CEMP progenitors using fluorine, Monthly Notices of the Royal Astronomical Society, Volume 498, Issue 3, November 2020, Pages 3549–3559] is available online at: https://doi.org/10.1093/mnras/staa2610. |
Keywords | astro-ph.sr, astro-ph.ga, stars: agb and post-agb, stars: chemically peculiar, stars: abundances, astronomy and astrophysics, space and planetary science |
Date Deposited | 15 May 2025 14:25 |
Last Modified | 31 May 2025 00:26 |
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