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arXiv · 0709.2604

Near-infrared spectroscopy of the very low mass companion to the hot DA white dwarf PG1234+482

P. R. Steele·M. R. Burleigh·P. D. Dobbie·M. A. Barstow
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Abstract

We present a near-infrared spectrum of the hot ($T_{\rm eff}$ $\approx$ 55,000 K) DA white dwarf PG 1234+482. We confirm that a very low mass companion is responsible for the previously recognised infrared photometric excess. We compare spectra of M and L dwarfs, combined with an appropriate white dwarf model, to the data to constrain the spectral type of the secondary. We find that uncertainties in the 2MASS $HK$ photometry of the white dwarf prevent us from distinguishing whether the secondary is stellar or substellar, and assign a spectral type of L0$\pm$1 (M9-L1).Therefore, this is the hottest and youngest ($\approx 10^6$ yr) DA white dwarf with a possible brown dwarf companion.

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P. R. Steele, M. R. Burleigh, P. D. Dobbie, M. A. Barstow. 2007-09-17. Near-infrared spectroscopy of the very low mass companion to the hot DA white dwarf PG1234+482. https://doi.org/10.1111/j.1365-2966.2007.12481.x

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