A Strontium-rich Ultra Metal-poor Star in the Atari Disk Component

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Auteurs principaux: Mardini, Mohammad K., Frebel, Anna, Chiti, Anirudh
Format: Preprint
Publié: 2024
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author Mardini, Mohammad K.
Frebel, Anna
Chiti, Anirudh
author_facet Mardini, Mohammad K.
Frebel, Anna
Chiti, Anirudh
contents We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J20500194$-$6613298 (J2050$-$6613; \mbox{[Fe/H] = $-4.05$}) selected from the Gaia BP/RP spectral catalog that belongs to the ancient Atari disk component. We obtained a high-resolution spectrum for the star with the MIKE spectrograph on the Magellan-Clay telescope. J2050$-$6613 displays a typical chemical abundance pattern for UMP stars, including carbon and zinc enhancements. In contrast, J2050$-$6613 shows extremely high [Sr/Fe] and [Sr/Ba] ratios compared to other stars in the [Fe/H] $<-4.0$ regime. J2050$-$6613 is most likely an early Population\,II star that formed from a gas cloud that was chemically enriched by a massive Population\,III hypernova (E $> 10^{52}$\,erg). Such a Population\,III core-collapse hypernova could simultaneously explain the origin of the abundance pattern of light and heavy elements of 2MASS~J2050$-$6613 if a large amount of Sr of $\sim10^{-5}$\,M$_{\odot}$ was produced, possibly by neutrino-driven \textbf{(wind)} ejecta. Therefore, the abundance pattern of 2MASS~J2050$-$6613 places important constraints on Sr-producing nucleosynthesis sources operating in the Atari progenitor at the earliest times.
format Preprint
id arxiv_https___arxiv_org_abs_2402_07046
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Strontium-rich Ultra Metal-poor Star in the Atari Disk Component
Mardini, Mohammad K.
Frebel, Anna
Chiti, Anirudh
Astrophysics of Galaxies
Solar and Stellar Astrophysics
We report on the discovery of the first ultra metal-poor (UMP) star 2MASS~J20500194$-$6613298 (J2050$-$6613; \mbox{[Fe/H] = $-4.05$}) selected from the Gaia BP/RP spectral catalog that belongs to the ancient Atari disk component. We obtained a high-resolution spectrum for the star with the MIKE spectrograph on the Magellan-Clay telescope. J2050$-$6613 displays a typical chemical abundance pattern for UMP stars, including carbon and zinc enhancements. In contrast, J2050$-$6613 shows extremely high [Sr/Fe] and [Sr/Ba] ratios compared to other stars in the [Fe/H] $<-4.0$ regime. J2050$-$6613 is most likely an early Population\,II star that formed from a gas cloud that was chemically enriched by a massive Population\,III hypernova (E $> 10^{52}$\,erg). Such a Population\,III core-collapse hypernova could simultaneously explain the origin of the abundance pattern of light and heavy elements of 2MASS~J2050$-$6613 if a large amount of Sr of $\sim10^{-5}$\,M$_{\odot}$ was produced, possibly by neutrino-driven \textbf{(wind)} ejecta. Therefore, the abundance pattern of 2MASS~J2050$-$6613 places important constraints on Sr-producing nucleosynthesis sources operating in the Atari progenitor at the earliest times.
title A Strontium-rich Ultra Metal-poor Star in the Atari Disk Component
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2402.07046