Model atmosphere analysis of the extreme DQ white dwarf GSC2U J131147.2+292348

D. Carollo*, D. Koester, A. Spagna, M. G. Lattanzi, S. T. Hodgkin

*Corresponding author for this work

    Research output: Contribution to journalLetterpeer-review

    11 Citations (Scopus)
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    A new model atmosphere analysis for the peculiar DQ white dwarf discovered by Carollo et al. (2002) is presented. The effective temperature and carbon abundance have been estimated by fitting both the photometric data (UBJVRFINJHK) and a low resolution spectrum (3500 < λ < 7500 Å) with a new model grid for helium-rich white dwarfs with traces of carbon (DQ stars). We estimate Teff ≃ 5120 ± 200 K and log[C/He] ≃ -5.8 ± 0.5, which make GSC2U J131147.2+292348 the coolest DQ star ever observed. This result indicates that the hypothetical transition from C2 to C2H molecules around Teff = 6000 K, which was inferred to explain the absence of DQ stars at lower temperatures, needs to be reconsidered.

    Original languageEnglish
    JournalAstronomy and Astrophysics
    Issue number1
    Publication statusPublished - Mar 2003

    Bibliographical note

    Copyright ESO 2003. First published in Astronomy and Astrophysics, Vol. 400, No. 1, published by EDP Sciences. The original publication is available at


    • Stars: Individual: GSC2U J131147.2+292348
    • Stars: Kinematics
    • Techniques: Spectroscopic
    • White dwarfs


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