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Trumpler 20 - an old and rich open cluster

Platais, I. ; Melo, C. ; Fulbright, J. P. ; Kozhurina-Platais, V. ; Figueira, P. ; Barnes, S. A. ; Méndez, R. A.

In: Monthly Notices of the Royal Astronomical Society, 2008, vol. 391, no. 3, p. 1482-1488

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    Titre
    • Trumpler 20 - an old and rich open cluster
    Auteur
    • Platais, I.. Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
    • Melo, C.. European Southern Observatory, Karl-Schwarzschild-Str 2, Garching bei München, Germany
    • Fulbright, J. P.. Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
    • Kozhurina-Platais, V.. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
    • Figueira, P.. Observatoire de Genève, 1290 Sauverny, Switzerland
    • Barnes, S. A.. Lowell Observatory, Flagstaff, AZ 86001, USA
    • Méndez, R. A.. Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2008, vol. 391, no. 3, p. 1482-1488. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:298907
    Summary
    We show that the open cluster Trumpler 20, contrary to the earlier findings, is actually an old Galactic open cluster. New CCD photometry and high-resolution spectroscopy are used to derive the main parameters of this cluster. At [Fe/H]=−0.11 for a single red giant star, the metallicity is slightly subsolar. The best fit to the colour-magnitude diagrams is achieved using a 1.3-Gyr isochrone with convective overshoot. The cluster appears to have a significant reddening at E(B−V) = 0.46 (for B0 spectral type), although for red giants this high reddening yields the colour temperature exceeding the spectroscopic Teff by about 200 K. Trumpler 20 is a very rich open cluster, containing at least 700 members brighter than MV=+4. It may extend over the field of view available in our study at 20 × 20 arcmin2