Repositório Digital

A- A A+

Young (α/Fe)-enhanced stars discovered by CoRoT and APOGEE : what is their origin?

.

Young (α/Fe)-enhanced stars discovered by CoRoT and APOGEE : what is their origin?

Mostrar registro completo

Estatísticas

Título Young (α/Fe)-enhanced stars discovered by CoRoT and APOGEE : what is their origin?
Autor Chiappini, C.C.M.
Anders, Friedrich
Rodrigues, Thaise da Silva
Miglio, Andrea
Montalbán, Josefina
Mosser, Benoît
Girardi, Leo Alberto
Valentini, Marica
Noels, Arlette
Morel , Thierry
Minchev, Ivan
Steinmetz, M.
Santiago, Basilio Xavier
Schultheis, Mathias
Martig, Marie
Costa, Luiz N. da
Maia, M.A.G.
Allende Prieto, Carlos
Assis Peralta, R. de
Hekker, Saskia
Themeßl, Nathalie
Kallinger, Thomas
Garcia, Rafael A.
Mathur, Savita
Baudin, Frederic
Beers, T.C.
Cunha, Katia
Harding, Paul
Holtzman, J.A.
Majewski, Steven Raymond
Mészáros, S.
Nidever, D.L.
Pan, K.
Schiavon, Ricardo P.
Shetrone, M.
Schneider, D.P.
Stassun, Keivan G.
Abstract We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [ /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 reliably obtained, although in smaller relative numbers. This might explain why these stars have not previously received attention. The young [ /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 because only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [ /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 than in other regions that are more frequently shocked by the passage of spiral arms. Moreover, this is where the mass return from older inner-disc stellar generations is expected to be highest (according to an inside-out disc-formation scenario), which additionally dilutes the in-situ gas. Other possibilities to explain these observations (e.g., a recent gas-accretion event) are also discussed.
Contido em Astronomy and astrophysics. Les Ulis. Vol. 576 (Apr. 2015), L12, 7 p.
Assunto Asterosismologia
Formacao de galaxias
[en] Asteroseismology
[en] Galaxy: abundances
[en] Galaxy: disk
[en] Galaxy: formation
[en] Galaxy: stellar content
[en] Stars: fundamental parameters
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/143886
Arquivos Descrição Formato
000996899.pdf (1.102Mb) Texto completo (inglês) Adobe PDF Visualizar/abrir

Este item está licenciado na Creative Commons License

Este item aparece na(s) seguinte(s) coleção(ões)


Mostrar registro completo

Percorrer



  • O autor é titular dos direitos autorais dos documentos disponíveis neste repositório e é vedada, nos termos da lei, a comercialização de qualquer espécie sem sua autorização prévia.
    Projeto gráfico elaborado pelo Caixola - Clube de Criação Fabico/UFRGS Powered by DSpace software, Version 1.8.1.