Young [$\alpha$/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?

Autor: Arlette Noels, M. A. G. Maia, Marie Martig, T. Morel, R. A. Garcia, Matthew Shetrone, Keivan G. Stassun, T. S. Rodrigues, Matthias Steinmetz, Sz. Meszaros, T. Kallinger, Paul Harding, Marica Valentini, Josefina Montalbán, D. P. Schneider, M. Schultheis, Friedrich Anders, J. A. Holtzman, R. de Assis Peralta, B. Mosser, S. Hekker, I. Minchev, L. N. da Costa, Andrea Miglio, C. Allende Prieto, Basilio X. Santiago, D. L. Nidever, N. Themeßl, S. R. Majewski, L. Girardi, S. Mathur, K. M. Cunha, F. Baudin, Cristina Chiappini, Timothy C. Beers, K. Pan, Ricardo P. Schiavon
Přispěvatelé: Leibniz-Institut für Astrophysik Potsdam (AIP), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), European Project: 338251,EC:FP7:ERC,ERC-2013-StG,STELLARAGES(2013), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2015
Předmět:
RED-GIANT STARS
Milky Way
fundamental parameters [stars]
MILKY-WAY DISK
Astrophysics
asteroseismology
Astrophysics::Cosmology and Extragalactic Astrophysics
Spectral line
Formacao de galaxias
Galaxy: disk
STELLAR POPULATIONS
SOLAR VICINITY
stellar content [Galaxy]
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Galaxy Astrophysics
QB
Physics
Galaxy: stellar content
Spiral galaxy
Galactic Center
1ST YEAR
abundances [Galaxy]
Astronomy and Astrophysics
ELEMENTAL ABUNDANCE
Alpha (navigation)
CHEMICAL ABUNDANCES
CHEMODYNAMICAL EVOLUTION
Astrophysics - Astrophysics of Galaxies
Chemical evolution
Stars
formation [Galaxy]
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Galaxy: formation
Asterosismologia
Galaxy: abundances
stars: fundamental parameters
Astrophysics::Earth and Planetary Astrophysics
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
disk [Galaxy]
NEARBY STARS
GALACTIC-CENTER
Zdroj: Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, 2015, 576, pp.L12. ⟨10.1051/0004-6361/201525865⟩
Chiappini, C, Anders, F, Rodrigues, T S, Miglio, A, Montalban, J, Mosser, B, Girardi, L, Valentini, M, Noels, A, Morel, T, Minchev, I, Steinmetz, M, Santiago, B X, Schultheis, M, Martig, M, da Costa, L N, Maia, M A G, Allende Prieto, C, Peralta, R D A, Hekker, S, Themessl, N, Kallinger, T, Garcia, R A, Mathur, S, Baudin, F, Beers, T C, Cunhall, K, Harding, P, Holtzman, J, Majewski, S, Meszaros, S, Nidever, D, Pan, K, Schiavon, R P, Shetrone, M D, Schneider, D P & Stassun, K 2015, ' Young [α/Fe]-enhanced stars discovered by CoRoT and APOGEE : What is their origin? ', Astronomy & Astrophysics, vol. 576, L12 . https://doi.org/10.1051/0004-6361/201525865
Astronomy and Astrophysics-A&A, EDP Sciences, 2015, 576, pp.L12. ⟨10.1051/0004-6361/201525865⟩
Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS
ISSN: 0004-6361
1432-0746
DOI: 10.1051/0004-6361/201525865⟩
Popis: We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [alpha/Fe] abundance ratios (as determined from APOGEE spectra) with respect to Solar values. Their existence is not explained by standard chemical evolution models of the Milky Way, and shows that the chemical-enrichment history of the Galactic disc is more complex. We find similar stars in previously published samples for which isochrone-ages could be robustly obtained, although in smaller relative numbers, which could explain why these stars have not received prior attention. The young [alpha/Fe]-rich stars are much more numerous in the CoRoT-APOGEE (CoRoGEE) inner-field sample than in any other high-resolution sample available at present, as only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [$\alpha$/Fe]-rich stars are not clearly thick-disc like, despite their rather large distances from the Galactic mid-plane. Our tentative interpretation of these and previous intriguing observations in the Milky Way is that these stars were formed close to the end of the Galactic bar, near corotation -- a region where gas can be kept inert for longer times, compared to other regions shocked more frequently by the passage of spiral arms. Moreover, that is where the mass return from older inner-disc stellar generations should be maximal (according to an inside-out disc-formation scenario), further diluting the in-situ gas. Other possibilities to explain these observations (e.g., a recent gas-accretion event) are also discussed.
Comment: Letter in press in Astronomy and Astrophysics (5 pages, 4 figures + 2 pages Appendix)
Databáze: OpenAIRE
Externí odkaz: