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The fraction of double degenerates among DA white dwarfs

P. F. L. Maxted·T. R. Marsh
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Abstract

We present the results of a radial velocity survey designed to measure the fraction of double degenerates among DA white dwarfs. The narrow core of the H-alpha line was observed twice or more for 46 white dwarfs yielding radial velocities accurate to a few km/s. This makes our survey the most sensitive to the detection of double degenerates undertaken to date. We found no new double degenerates in our sample, though H-alpha emission from distant companions is seen in two systems. Two stars known to be double degenerates prior to our observations are included in the analysis. We find a 95% probability that the fraction of double degenerates among DA white dwarfs lies in the range [0.017,0.19].

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P. F. L. Maxted, T. R. Marsh. 2000-05-23. The fraction of double degenerates among DA white dwarfs. https://doi.org/10.1046/j.1365-8711.1999.02635.x

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