The molecular spectrum of sunspots

Citation

Webber, John Clinton (1970) The molecular spectrum of sunspots. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/FKJP-0C31. https://resolver.caltech.edu/CaltechETD:etd-05012008-151521

Abstract

The sunspot spectrum shows many molecular lines, of which some have been identified. These lines are formed farther out in the sunspot atmosphere than the atomic lines or the continuum, and are thus useful for probing the outer layers. Photographic spectrograms were obtained for three different sunspots under carefully selected seeing conditions, showing molecular absorption lines due to MgH, CaH, and TiO. Analysis led to estimates of the effective rotational temperatures of each; in the case of CaH, no definite conclusions could be drawn. Predicted rotational temperatures and observational f-values were calculated on the basis of model umbral atmospheres due to several authors. A new model was derived from the molecular lines measured here, and shown to differ widely from previous models. The usefulness of photographic spectra for this purpose is seriously questioned, and suggestions are made for new observations.

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