Local (thick-disc) white dwarfs and the Galactic mass budget

Authors

  • K. Fuhrmann,

    Corresponding author
    1. Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
    2. Isaac Newton Group of Telescopes, Apartado 321, E-38700 Santa Cruz de La Palma, Spain
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  • R. Chini,

    1. Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
    2. Instituto de Astronomía, Universidad Católica del Norte, Avenida Angamos 0610, Casilla 1280, Antofagasta, Chile
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  • V. H. Hoffmeister,

    1. Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
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  • J. Bernkopf

    1. University of Applied Sciences Augsburg, An der Hochschule 1, D-86161 Augsburg, Germany
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E-mail: klaus@ing.iac.es

ABSTRACT

The stars of the solar neighbourhood essentially originate from two stellar populations: Population I (the thin disc) and Population II (the thick disc). Recently, we completed an unbiased sample of long-lived solar-type stars and demonstrated that the local normalization of the thick disc versus thin disc is about 20 per cent. In this second paper, we present the observational evidence that at least this percentage is also met in the realm of their degenerate counterparts and may even be as high as one-third. Along with the results from the solar-type stars, this is a direct confirmation of the thick disc being the massive and dark baryonic population of the Milky Way.

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