The metal content of the bulge globular cluster NGC 6528

• Autor(a) principal: Zoccali, Manuela
• Data de Publicação: 2004
• Outros Autores: Barbuy, Beatriz, Hill, Vanessa, Ortolani, Sergio, Renzini, Alvio, Bica, Eduardo Luiz Damiani, Momany, Yazan, Pasquini, Luca, Minniti, Dante, Rich, Robert Michael
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/98767
• topic: Estrelas gigantes; Aglomerados globulares; Atmosferas estelares; Composicao estelar; Fotometria estelar; Espectros estelares; Fontes ultravioletas (astronômicas); Galaxy: bulge; Globular clusters: individual: NGC 6528; Stars: abundances; Stars: atmospheres

High resolution spectra of five stars in the bulge globular cluster NGC 6528 were obtained at the 8m VLT UT2-Kueyen telescope with the UVES spectrograph. Out of the five stars, two of them showed evidence of binarity. The target stars belong to the horizontal and red giant branch stages, at 4000 < Teff < 4800 K. Multiband V, I, J, H, Ks photometry was used to derive initial effective temperatures and gravities. The main purpose of this study is the determination of metallicity and elemental ratios for this template bulge cluster, as a basis for the fundamental calibration of metal-rich populations. The present analysis provides a metallicity [Fe/H] = −0.1 ± 0.2 and the α-elements O, Mg and Si, show [α/Fe] ≈ +0.1, whereas Ca and Ti are around the solar value or below, resulting in an overall metallicity Z ≈ Zѳ.