Evidence of redshifts in the average solar line profiles of C iv and Si iv from OSO-8 observations |
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| Authors: | D Roussel-Dupré R A Shine |
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| Institution: | (1) Institute for Astronomy, University of Hawaii, Woodlawn Drive, 2680 Honolulu, Hawaii, U.S.A.;(2) NASA-Goddard Space Flight Center, Code 685, Building 21-1bs, 20771 Greenbelt, Md, U.S.A. |
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| Abstract: | Measurements of the C iv 1548 Å and Si iv 1393 Å lines made with the University of Colorado Ultraviolet Spectrometer on board OSO-8 show that the mean profiles are redshifted at disk center. Assuming these lines to be optically thin, we measure an apparent average downflow of material in the 50 000 to 100 000 K temperature range which is weighted by the emission measure in these lines. The magnitude of the redshift varies from 6–17 km s–1 with a mean of 12 km s–1 and is persistent at least on the order of months, which is the time covered by the observations presented in this paper. Pneuman and Kopp (1978) have demonstrated that the flux of material associated with this downflow is of the same order of magnitude as the flux of material being carried upward in spicules. Thus, it is possible that material observed to be downflowing in C iv and Si iv has its origins in the upward moving spicule material. |
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