VLT-UVES analysis of 5 giants in 47 Tucanae

¹ Universidade de São Paulo, IAG, Rua do Matão 1226, Cidade Universitária, São Paulo 05508-900, Brazil e-mail: [abrito;barbuy]@astro.iag.usp.br
² Università di Padova, Dipartimento di Astronomia, Vicolo dell'Osservatorio 2, 35122 Padova, Italy e-mail: ortolani@pd.astro.it
³ Observatoire de Paris-Meudon, 92195 Meudon Cedex, France e-mail: Vanessa.Hill@obspm.fr
⁴ Universidad Catolica de Chile, Department of Astronomy & Astrophysics, Casilla 306, Santiago 22, Chile e-mail: [dante;mzoccali]@astro.puc.cl
⁵ Princeton University Observatory, Peyton Hall, Princeton, NJ 08544, USA
⁶ European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei München, Germany e-mail: [arenzini;lpasquin]@eso.org
⁷ Universidade Federal do Rio Grande do Sul, Departamento de Astronomia, CP 15051, Porto Alegre 91501-970, Brazil e-mail: bica@if.ufrgs.br
⁸ UCLA, Department of Physics & Astronomy, 8979 Math-Sciences Building, Los Angeles, CA 90095-1562, USA e-mail: rmr@astro.ucla.edu

Received: 10 July 2004
Accepted: 10 January 2005

Abstract

High resolution spectra of 5 giants, including a horizontal branch star, of the metal-rich globular cluster 47 Tucanae were obtained with the UVES spectrograph at the 8 m VLT UT2-Kueyen telescope. The atmospheric parameters (T_eff, log g, [Fe/H], v_t) were derived from VIJK photometry and spectroscopic data based on Fe I and Fe II lines. Fe I and Fe II iron abundances and respective total errors [Fe I/H] = – and [Fe II/H] = – are found. Abundances of α (O, Mg, Ca, Si, Ti), odd-Z (Na, Al), s- (Ba, La, Zr), and r-process (Eu) elements were determined by means of spectrum synthesis. The main results are , [Mg/Fe] ≈ [Si/Fe] ≈ [Ti/Fe] = +, , and . Overabundances of the α-elements O, Mg, Si and Ti, and of Eu are similar to those seen in halo metal-poor stars, whereas a solar Ca-to-Fe ratio resembles the values found in bulge stars. An overall metallicity or [M/H] = –0.45 is thus obtained, as is a mean heliocentric radial velocity  km s^-1.