The fraction of double degenerates among DA white dwarfs |
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Authors: | P F L Maxted T R Marsh |
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Institution: | University of Southampton, Department of Physics and Astronomy, Highfield, Southampton SO17 1BJ |
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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 line was observed twice or more for 46 white dwarfs yielding radial velocities accurate to a few km s1. 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 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 per cent probability that the fraction of double degenerates among DA white dwarfs lies in the range 0.017, 0.19]. |
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Keywords: | techniques: radial velocities binaries: spectroscopic stars: evolution stars: rotation supernovae: general white dwarfs |
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