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High-resolution spectroscopic study of extremely metal-poor stars in the Large Magellanic Cloud.
- Source :
-
Monthly Notices of the Royal Astronomical Society . Feb2024, Vol. 528 Issue 1, p1065-1080. 16p. - Publication Year :
- 2024
-
Abstract
- We present detailed abundance results based on Ultraviolet and Visual Echelle Spectrograph high-dispersion spectra for seven very and extremely metal-poor stars in the Large Magellanic Cloud (LMC). We confirm that all seven stars, two of which have [Fe/H] ≤ −3.0, are the most metal-poor stars discovered so far in the Magellanic Clouds. The element abundance ratios are generally consistent with Milky Way halo stars of similar [Fe/H] values. We find that two of the more metal-rich stars in our sample are enhanced in r-process elements. This result contrasts with the literature, where all nine metal-poor LMC stars with higher [Fe/H] values than our sample were found to be rich in r-process elements. The absence of r-process enrichment in stars with lower [Fe/H] values is consistent with a minimum delay time-scale of ∼100 Myr for the neutron star binary merger process to generate substantial r-process enhancements in the LMC. We find that the occurrence rate of r-process enhancement (r-I or r-II) in our sample of very and extremely metal-poor stars is statistically indistinguishable from that found in the Milky Way's halo, although including stars from the literature sample hints at a larger r-II frequency the LMC. Overall, our results shed light on the earliest epochs of star formation in the LMC that may be applicable to other galaxies of LMC-like mass. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 528
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 175011137
- Full Text :
- https://doi.org/10.1093/mnras/stae081