Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
The O-Na and Mg-Al anticorrelations in turn-off and early subgiants in globular clusters
Autore:
Gratton, RG; Bonifacio, P; Bragaglia, A; Carretta, E; Castellani, V; Centurion, M; Chieffi, A; Claudi, R; Clementini, G; DAntona, F; Desidera, S; Francois, P; Grundahl, F; Lucatello, S; Molaro, P; Pasquini, L; Sneden, C; Spite, F; Straniero, O;
Indirizzi:
Osservatorio Astron Padova, I-35122 Padua, Italy Osservatorio Astron Padova Padua Italy I-35122 ova, I-35122 Padua, Italy Osservatorio Astron Trieste, I-34131 Trieste, Italy Osservatorio Astron Trieste Trieste Italy I-34131 I-34131 Trieste, Italy Osservatorio Astron Bologna, I-40127 Bologna, Italy Osservatorio Astron Bologna Bologna Italy I-40127 I-40127 Bologna, Italy Univ Pisa, Dipartimento Fis, I-56100 Pisa, Italy Univ Pisa Pisa Italy I-56100 Pisa, Dipartimento Fis, I-56100 Pisa, Italy CNR, Ist Astrofis Spaziale, I-00185 Rome, Italy CNR Rome Italy I-00185CNR, Ist Astrofis Spaziale, I-00185 Rome, Italy Osservatorio Astron Roma, I-00136 Rome, Italy Osservatorio Astron Roma Rome Italy I-00136 on Roma, I-00136 Rome, Italy Univ Padua, Dipartimento Astron, I-35122 Padua, Italy Univ Padua Padua Italy I-35122 Dipartimento Astron, I-35122 Padua, Italy European So Observ, Garching, Germany European So Observ Garching Germany ropean So Observ, Garching, Germany Univ Aarhus, Dept Astron, Aarhus, Denmark Univ Aarhus Aarhus DenmarkUniv Aarhus, Dept Astron, Aarhus, Denmark Univ Texas, Austin, TX 78712 USA Univ Texas Austin TX USA 78712Univ Texas, Austin, TX 78712 USA Observ Meudon, F-92195 Meudon, France Observ Meudon Meudon France F-92195 bserv Meudon, F-92195 Meudon, France Osservatorio Astron Collurania, Collurania, Italy Osservatorio Astron Collurania Collurania Italy ania, Collurania, Italy
Titolo Testata:
ASTRONOMY AND ASTROPHYSICS
fascicolo: 1, volume: 369, anno: 2001,
pagine: 87 - 98
SICI:
0004-6361(200104)369:1<87:TOAMAI>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
METAL-POOR STARS; HIGH-DISPERSION SPECTROSCOPY; MAIN-SEQUENCE STARS; RED GIANT STARS; LIGHT-ELEMENTS; CN BANDS; ABUNDANCES; LITHIUM; SODIUM; ALUMINUM;
Keywords:
stars : abundances; stars : evolution; stars : population II; Galaxy : globular clusters;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Gratton, RG Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy Osservatorio Astron Padova Vicolo Osservatorio 5 Padua Italy I-35122
Citazione:
R.G. Gratton et al., "The O-Na and Mg-Al anticorrelations in turn-off and early subgiants in globular clusters", ASTRON ASTR, 369(1), 2001, pp. 87-98

Abstract

High dispersion spectra (R greater than or similar to 40 000) for a quite large number of stars at the main sequence turn-off and at the base of the giant branch in NGC 6397 and NGC 6752 were obtained with the UVES on Kueyen(VLT UT2). The [Fe/H] values we found are -2.03 +/- 0.02 +/- 0.04 and -1.42 +/- 0.02 +/- 0.04 for NGC 6397 and NGC 6752 respectively, where the firsterror bars refer to internal and the second ones to systematic errors (within the abundance scale defined by our analysis of 25 subdwarfs with good Hipparcos parallaxes). In both clusters the [Fe/H]'s obtained for TO-stars agree perfectly (within a few percent) with that obtained for stars at the base of the RGB. The [O/Fe] = 0.21 +/- 0.05 value Re obtain for NGC 6397 is quite low, but it agrees with previous results obtained for giants in this cluster. Moreover, the star-to-star scatter in both O and Fe is very small,indicating that this small mass cluster is chemically very homogenous. On the other hand, our results show clearly and for the first time that the O-Na anticorrelation (up to now seen only for stars on the red giant branchesof globular clusters) is present among unevolved stars in the globular cluster NGC 6752, a more massive cluster than NGC 6397. A similar anticorrelation is present also for Mg and Al, and C and N. It is very difficult to explain the observed Na-OI and Mg-Al anticorrelation in NGC 6752 stars by a deep mixing scenario; we think it requires some non internal mechanism.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 15:08:57