Abstract
view Abstract Citations (56) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optically thick lines in a quiescent prominence - Profiles of Lyman-alpha, Lyman-beta /H I/, K and H /Mg II/, and K and H /Ca II/ lines with the OSO 8 LPSP instrument Vial, J. C. Abstract The first set of simultaneous measurements are presented of H I Lyman-alpha and Lyman-beta, Ca II K and H, and Mg II k and h lines in a quiescent prominence. It is found that: (1) Ca II resonance lines have low opacity, with an optical thickness at the center of the K line varying between 1.4 and 3.2, and nonthermal velocities ranging from 5 to 9 km/sec.; (2) the resonance lines of Mg II, as measured in the whole prominence, depart from Gaussian profiles and are unexplainably broader than the corresponding Ca II ones. The observed Mg II and Ca II 'inverted' intensity ratios may be due to different incident intensities ratios; and (3) the Lyman-alpha and Lyman-beta lines of H I have the same reversals as the chromospheric lines in bright regions, and unreversed profiles may be observed in darker regions. The intensities are larger than the diluted incident radiation, and the opacity reaches values of 100,000. Publication: The Astrophysical Journal Pub Date: February 1982 DOI: 10.1086/159639 Bibcode: 1982ApJ...253..330V Keywords: Line Spectra; Optical Thickness; Solar Prominences; Solar Spectra; Solar X-Rays; Calcium Isotopes; H Lines; Hydrogen Isotopes; K Lines; Lyman Spectra; Magnesium Isotopes; Spectroheliographs; Solar Physics full text sources ADS |
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