Abstract
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 language | English |
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Journal | Astronomy and Astrophysics |
Volume | 393 |
Issue number | 3 |
Publication status | Published - 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 http://dx.doi.org/10.1051/0004-6361:20021130Keywords
- Astrometry
- Stars: carbon
- Stars: individual: GSC2U J131147.2+292348
- Stars: kinematics
- Techniques: spectroscopic
- White dwarfs