A progress report on the carbon dominated atmosphere white dwarfs

@article{Dufour2009APR,
  title={A progress report on the carbon dominated atmosphere white dwarfs},
  author={P. Dufour and James William Liebert and Brandon J. Swift and Gilles Fontaine and Tuguldur Sukhbold},
  journal={arXiv: Solar and Stellar Astrophysics},
  year={2009},
  volume={172},
  pages={012012}
}
Recently, Dufour et al. (2007) reported the unexpected discovery that a few white dwarfs found in the Sloan Digital Sky Survey had an atmosphere dominated by carbon with little or no trace of hydrogen and helium. Here we present a progress report on these new objects based on new high signal-to-noise follow-up spectroscopic observations obtained at the 6.5m MMT telescope on Mount Hopkins, Arizona. 

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