Two solar observations obtained with the Ultraviolet Spectrometer on board Voyager 2 are presented in absolute flux units . The spectra, that are part of a larger collection of solar observations, cover the wavelength range of 50-125 nm with an effective resolution of about 3 nm. They were recorded in December 1985 (low solar activity) and in September 1989 (high solar activity), when the spacecraft was at a distance from the Earth of 18.9 and 30.0 AU, respectively. The data are used to estimate the ultraviolet irradiance variability, from minimum to maximum, during solar cycle 22 with particular interest in the region of shorter wavelengths, where very few measurements have been performed in the past years. The recent calibration of the Voyager solar observations indicates an higher flux level for the spectral region under 91.2 nm as well as for the H Lyalpha line than the ones expected from previous measurements.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1994