Abstract
We present the Lyman α sky background data obtained by the UV spectrometers on the Voyager 1 and 2 spacecraft between 1993 and early 1998. These data which consist of special maneuvers dedicated to the study of the Lyα pattern in the outer heliosphere represent a unique opportunity to constrain the hydrogen distribution in the outer heliosphere.A first analysis of the data is presented. This consists of a comparison with a Hot Model of the hydrogen distribution combined with a radiative transfer calculation in the hypothesis of Complete Frequency Redistribution. We confirm previous measurements showing the existence of an excess in Lyα background in the upwind direction. The radial variation of the upwind intensity measurements found from the two Voyager data sets are different. The Voyager 1 data show a radial decrease following r -1.4 whereas the Voyager 2 data yield r -0.79. These values have been derived after correction for solar flux variations using the SOLSTICE/UARS data set.
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Quémerais, E., Sandel, B.R., Bertaux, J. et al. Outer Heliosphere Ly-α Measurements: 1993 to 1998. Astrophysics and Space Science 274, 123–132 (2000). https://doi.org/10.1023/A:1026591705751
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DOI: https://doi.org/10.1023/A:1026591705751