Discovery of a peculiar DQ white dwarf

D. Carollo*, S. T. Hodgkin, A. Spagna, R. L. Smart, M. G. Lattanzi, B. J. McLean, D. J. Pinfield

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)


    We report the discovery of a new carbon rich white dwarf that was identified during a proper motion survey for cool white dwarfs based on photographic material used for the construction of the Guide Star Catalog II. Its large proper motion (μ ≃ 0.48 arcsec/yr) and faint apparent magnitude (V ≃ 18.7) suggest a nearby object of low luminosity. A low-resolution spectrum taken with the William Herschel Telescope clearly shows strong C2 Deslandres-d'Azambuja and Swan bands, which identify the star as a DQ white dwarf. The strength of the Deslandres-d'Azambuja bands and the depression of the continuum in the Swan-band region are signs of enhanced carbon abundance for the given Teff. Comparison of our spectrophotometric data to published synthetic spectra suggests 6000 K < Teff < 8000 K, although further analysis with specialized synthetic models appear necessary to derive both Teff and chemical composition. Finally, the range of spatial velocity estimated for this object makes it a likely member of the halo or thick disk population.

    Original languageEnglish
    JournalAstronomy and Astrophysics
    Issue number3
    Publication statusPublished - Oct 2002

    Bibliographical note

    Copyright ESO 2002. First published in Astronomy and astrophysics, Vol. 393 and No. 3, published by EDP Sciences. The original publication is available at


    • Astrometry
    • Stars: carbon
    • Stars: individual: GSC2U J131147.2+292348
    • Stars: kinematics
    • Techniques: spectroscopic
    • White dwarfs


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