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Titolo:
First results of UVES at VLT: abundances in the Sgr dSph
Autore:
Bonifacio, P; Hill, V; Molaro, P; Pasquini, L; Di Marcantonio, P; Santin, P;
Indirizzi:
Osservatorio Astron Trieste, I-34131 Trieste, Italy Osservatorio Astron Trieste Trieste Italy I-34131 I-34131 Trieste, Italy European So Observ, D-85748 Garching, Germany European So Observ Garching Germany D-85748 v, D-85748 Garching, Germany
Titolo Testata:
ASTRONOMY AND ASTROPHYSICS
fascicolo: 2, volume: 359, anno: 2000,
pagine: 663 - 668
SICI:
0004-6361(200007)359:2<663:FROUAV>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
SAGITTARIUS DWARF GALAXY; MAGELLANIC-CLOUD; CHEMICAL-COMPOSITION; SPHEROIDAL GALAXY; STELLAR CONTENT;
Keywords:
stars : abundances; stars : individual : Sgr 143 galaxies : abundances; galaxies : dwarf; galaxies : individual : Sgr dSPH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
20
Recensione:
Indirizzi per estratti:
Indirizzo: Bonifacio, P Osservatorio Astron Trieste, Via GB Tiepolo 11, I-34131 Trieste, Italy Osservatorio Astron Trieste Via GB Tiepolo 11 Trieste Italy I-34131
Citazione:
P. Bonifacio et al., "First results of UVES at VLT: abundances in the Sgr dSph", ASTRON ASTR, 359(2), 2000, pp. 663-668

Abstract

Two giants of the Sagittarius dwarf spheroidal have been observed with theUVES spectrograph on the ESO 8.2m Kueyen telescope, during the commissioning of the instrument. Sgr 139 has [Fe/H] = -0.28 and Sgr 143 [Fe/H]= -0.21,these values are considerably higher than photometric estimates of the metallicity of the main population of Sgr. We derived abundances for O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Ba, La, Ce, Nd and Eu; the abundance ratios found are essentially solar with a few exceptions: Na shows a strong over-deficiency, the heavy elements Ba to Eu, are overabundant, while Y is underabundant. The high metallicity derived implies that the Sgrgalaxy has experienced a high level of chemical processing. The stars had been selected to be representative of the two main stellar populations of Sagittarius, however, contrary to what expected from the photometry, the twostars show a very similar chemical composition. We argue that the most likely explanation for the difference in the photometry of the two stars is a different distance, Sgr 143 being about 2 Kpc nearer than Sgr 139. This result suggests that the interpretation of colour - magnitude diagrams of Sgr is more complex than previously thought and the effect of the line of Sightdepth should not be neglected. It also shows that spectroscopic abundancesare required for a correct interpretation of Sgr populations.

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Documento generato il 19/09/20 alle ore 13:48:21