Academic Journal
GHOST commissioning science results - II: a very metal-poor star witnessing the early galactic assembly
| العنوان: | GHOST commissioning science results - II: a very metal-poor star witnessing the early galactic assembly |
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| المؤلفون: | Sestito, Federico, Hayes, Christian R., Venn, Kim A., Jensen, Jaclyn, Mcconnachie, Alan W., Pazder, John, Waller, Fletcher, Ardern-Arentsen, Anke, Jablonka, Pascale, Martin, Nicolas F., Matsuno, Tadafumi, Navarro, Julio F., Starkenburg, Else, Vitali, Sara, Bassett, John, Berg, Trystyn A. M., Diaz, Ruben, Edgar, Michael L., Firpo, Veronica, Gomez-Jimenez, Manuel, Kalari, Venu, Lambert, Sam, Lawrence, Jon, Robertson, Gordon, Ruiz-Carmona, Roque, Salinas, Ricardo, Sebo, Kim M., Venkatesan, Sudharshan |
| المساهمون: | Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE31-0017,Pristine,Pristine — Sondage des premières étoiles Galactiques(2018) |
| المصدر: | ISSN: 0035-8711. |
| بيانات النشر: | CCSD Oxford University Press (OUP): Policy P - Oxford Open Option A |
| سنة النشر: | 2024 |
| مصطلحات موضوعية: | stars: kinematics and dynamics, stars: Population II, Galaxy: abundances, Galaxy: bulge, Galaxy: evolution, Galaxy: formation, [SDU]Sciences of the Universe [physics] |
| الوصف: | International audience ; This study focuses on Pristine$\_180956.78$-294759.8 (hereafter P180956, [Fe/H] = -1.95 ± 0.02), a star selected from the Pristine Inner Galaxy Survey (PIGS), and followed-up with the recently commissioned Gemini High-resolution Optical SpecTrograph (GHOST) at the Gemini South telescope. The GHOST spectrograph's high efficiency in the blue spectral region (3700-4800 Å) enables the detection of elemental tracers of early supernovae (e.g. Al, Mn, Sr, and Eu). The star exhibits chemical signatures resembling those found in ultrafaint dwarf (UFD) systems, characterized by very low abundances of neutron-capture elements (Sr, Ba, and Eu), which are uncommon among stars in the Milky Way halo. Our analysis suggests that P180956 bears the chemical imprints of a small number (2 or 4) of low-mass hypernovae ($\sim 10{-}15{\rm \, M_\odot }$), which are needed to mostly reproduce the abundance pattern of the light-elements (e.g. [Si, Ti/Mg, Ca] ~0.6), and one fast-rotating intermediate-mass supernova ($\sim 300{\rm \, km \ s^{-1}}$, $\sim 80{-}120{\rm \, M_\odot }$), which is the main channel contributing to the high [Sr/Ba] (~+1.2). The small pericentric ($\sim 0.7{\rm \, kpc}$) and apocentric ($\sim 13{\rm \, kpc}$) distances and its orbit confined to the plane ($\lesssim 2{\rm \, kpc}$) indicate that this star was likely accreted during the early Galactic assembly phase. Its chemo-dynamical properties suggest that P180956 formed in a system similar to a UFD galaxy accreted either alone, as one of the low-mass building blocks of the proto-Galaxy, or as a satellite of Gaia-Sausage-Enceladus. The combination of Gemini's large aperture with GHOST's high efficiency and broad spectral coverage makes this new spectrograph one of the leading instruments for near-field cosmology investigations. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| Relation: | info:eu-repo/semantics/altIdentifier/arxiv/2308.07366; ARXIV: 2308.07366; BIBCODE: 2024MNRAS.528.4838S |
| DOI: | 10.1093/mnras/stae244 |
| الاتاحة: | https://insu.hal.science/insu-04465174 https://insu.hal.science/insu-04465174v1/document https://insu.hal.science/insu-04465174v1/file/stae244.pdf https://doi.org/10.1093/mnras/stae244 |
| Rights: | http://creativecommons.org/licenses/by/ ; info:eu-repo/semantics/OpenAccess |
| رقم الانضمام: | edsbas.68C66547 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1093/mnras/stae244 |
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