A statistical study of prominence excitation.

Abstract

view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A statistical study of prominence excitation. Newkirk, Gordon A., Jr. Abstract In order to study the relations which exist between the excitation and the kinematic behavior of a prominence, the author has measured emission line ratios of a number of prominences which have been classified according to the Menzel-Evans scheme. The measurement was greatly facilitated by a special photometer, constructed at Sacramento Peak, which permitted the comparison of the prominence spectrum with a carefully calibrated, juxtaposed, synthetic spectrum. The spectrograms employed were the routine, Sacramento Peak coronal plates. Prominence movies permitted the kinematic classification of each prominence examined. Although a total of twelve emission lines appeared on the plates, only the pair H, and D3 were of sufficient strength in all spectra for their ratio to constitute a reasonably broad criterion of excitation. In addition to measuring the emission line intensities, I also checked each spectrum for the following features: (i)The presence of a continuous spectrum from the prominence. (2)Any anomalies (abnormal strengthening, broadening, or radial velocity shifts) in the coronal lines at 6702, 6374, or 5303 A. (3)The presence of the yellow coronal line at 5694 A. A natural division seems to exist between those prominences where I ~ Ha/D3 <35 and those where_Ha/D3> 35. High excitation objects fall * On leave to U. S. Armv. in the former group; low excitation, in the latter. The division of the various kinematic types into high and low excitation objects appears below: High Excitation Low Excitation Loops Hedges Trees Mounds Coronal Streamers The data were insufficient to permit classification of the other types of prominences. One fact which emerged from the study is that, among the 52 prominences examined, there seems to be no disposition toward high or low excitatioi~ of either the spot or the non-spot prominences. Likewise, the prominence continuum appears as frequently among the high excitation objects as among the low. It is of particular interest that coronal anomalies occur almost exclusively near the prominences of high excitation. Sacramento Peak, Sunspot, N. Mcx. Publication: The Astronomical Journal Pub Date: October 1954 DOI: 10.1086/107038 Bibcode: 1954AJ.....59..330N full text sources ADS |