view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Physical conditions in solar prominences. Orrall, F. Q. ; Athay, R. G. Abstract Spectra of four solar limb-prominences, obtained with slitless spectrographs at eclipse, are analyzed to determine electron density, Ne, and kinetic temperature, Te For three of the prominences, the data consist of the continuous emission XX65oo-35oo. Data for the fourth prominence include the continuous emission X~4Ioo- 3600 and line emission in several hydrogen, helium and metal lines. We assume that Te and Ne are constant throughout each prominence. From the ratio of the Balmer free-bound em ission to the remaining components of the continuous emission at X3647, we limit P0 in the four prominences to the range 5200 to 2.5 X i~~. We reduce the upper limit on Te to 2 X i~~ for the three prominences for which we have extensive continuum data. At Te = 5500; Ne = 1010 and at Te = 2 >c i&, N0 = 2.7 X 1011. Analysis of the hydrogen and helium line data for the fourth prominence yields the following conclusions: (i) the optical thickness of the central part of the prominence in the center of Ha is less than or near unity and none of the observed hydrogen and helium line intensities are seriously affected by self-absorption; (2) the hydrogen energy levels and the helium triplet energy levels are over-populated relative to the thermodynamic equilibrium populations at Te; (3) helium is predominantly singly ionized if the hydrogen: helium ratio is near 10: I; (4) P0 is near the upper limit of 2.5 X i~~ and Ne > 10"; (5) the prominence is in a steady-state with the energy radiated balanced by an external energy supply. This work was supported by the Geophysics Research Directorate, Air Force Cambridge Research Center. Sacramento Peak Observatory, N. M., and High Altitude Observatory, Boulder, Colo. Publication: The Astronomical Journal Pub Date: 1957 DOI: 10.1086/107623 Bibcode: 1957AJ.....62R..28O full text sources ADS |