The Pristine survey IV: approaching the Galactic metallicity floor with the discovery of an ultra-metal-poor star
| Autor: | Piercarlo Bonifacio, D. S. Aguado, A. Arentsen, Eline Tolstoy, Rubén Sánchez-Janssen, Patrick Côté, Elisabetta Caffau, Kim A. Venn, Vanessa Hill, Julio F. Navarro, Nicolas Longeard, Carlos Allende Prieto, Morgan Fouesneau, Pascale Jablonka, Raymond G. Carlberg, Marc Gentile, Federico Sestito, Else Starkenburg, Collin Kielty, Helmer H. Koppelman, Jonay I. González Hernández, Nicolas F. Martin, Kris Youakim, Carmela Lardo, Alan W. McConnachie |
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| Přispěvatelé: | Astronomy, Starkenburg E., Aguado D.S., Bonifacio P., Caffau E., Jablonka P., Lardo C., Martin N., Sanchez-Janssen R., Sestito F., Venn K.A., Youakim K., Prieto C.A., Arentsen A., Gentile M., Hernandez J.I.G., Kielty C., Koppelman H.H., Longeard N., Tolstoy E., Carlberg R.G., Cote P., Fouesneau M., Hill V., McConnachie A.W., Navarro J.F., Galaxies, Etoiles, Physique, Instrumentation (GEPI), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), National Research Council of Canada (NRC), 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), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
photometry
stars: abundances Metallicity media_common.quotation_subject 1st stars FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics telescope Star (graph theory) 01 natural sciences Galactic halo Metal hamburg/eso survey 0103 physical sciences Galaxy formation and evolution Astrophysics::Solar and Stellar Astrophysics 010306 general physics 010303 astronomy & astrophysics ComputingMilieux_MISCELLANEOUS Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics media_common [PHYS]Physics [physics] Physics Galaxy: evolution abundance [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] Astronomy and Astrophysics stars: abundances Galaxy: abundances Galaxy: evolution Galaxy: formation Galaxy: halo Astrophysics - Solar and Stellar Astrophysics Astrophysics - Astrophysics of Galaxies model atmospheres Astrophysics - Astrophysics of Galaxies chemical-compositions Universe sky survey Galaxy: halo Galaxy: abundance Stars Astrophysics - Solar and Stellar Astrophysics lithium 13. Climate action Space and Planetary Science Galaxy: formation Astrophysics of Galaxies (astro-ph.GA) visual_art visual_art.visual_art_medium Galaxy: abundances Astrophysics::Earth and Planetary Astrophysics halo-stars |
| Zdroj: | Monthly Notices of the Royal Astronomical Society, 481(3), 3838-3852. Oxford University Press Monthly Notices of the Royal Astronomical Society Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2018, 481 (3), pp.3838-3852. ⟨10.1093/mnras/sty2276⟩ |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/sty2276 |
| Popis: | The early Universe presented a star formation environment that was almost devoid of heavy elements. The lowest metallicity stars thus provide a unique window into the earliest Galactic stages, but are exceedingly rare and difficult to find. Here we present the discovery of an ultra-metal-poor star, Pristine_221.8781+9.7844, using narrow-band Ca H&K photometry from the Pristine survey. Follow-up medium and high-resolution spectroscopy confirms the ultra-metal-poor nature of Pristine_221.8781+9.7844 ([Fe/H] = -4.66 +/- 0.13 in 1D LTE) with an enhancement of 0.3-0.4 dex in alpha-elements relative to Fe, and an unusually low carbon abundance. We derive an upper limit of A(C) = 5.6, well below typical A(C) values for such ultra metal-poor stars. This makes Pristine_221.8781+9.7844 one of the most metal-poor stars; in fact, it is very similar to the most metal-poor star known (SDSS J102915+172927). The existence of a class of ultra metal-poor stars with low(er) carbon abundances suggest that there must have been several formation channels in the early Universe through which long-lived, low-mass stars were formed. Re-submitted to MNRAS after minor revisions |
| Databáze: | OpenAIRE |
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