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A model of a sunspot chromosphere based on OSO 8 observationsOSO 8 spectrometer observations of the H I, Mg II, and Ca II resonance lines of a large quiet sunspot during November 16-17, 1975, along with a C IV line of that event obtained by a ground-based spectrometer, are analyzed together with near-simultaneous ground-based Stokes measurements to yield an umbral chromosphere and transition region model. Features of this model include a chromosphere that is effectively thin in the resonance lines of H I and Mg II, while being saturated in Ca II, and an upper chromospheric structure similar to that of quiet-sun models. The similarity of the upper chromosphere of the sunspot umbra to the quiet-sun chromosphere suggests that the intense magnetic field plays only a passive role in the chromospheric heating mechanism, and the observations cited indicate that solar-type stars with large areas of ordered magnetic flux would not necessarily exhibit extremely active chromosphere.
Document ID
19820052253
Document Type
Reprint (Version printed in journal)
Authors
Lites, B. W. (National Center for Atmospheric Research Boulder, CO, United States)
Skumanich, A. (High Altitude Observatory Boulder, CO, United States)
Date Acquired
August 10, 2013
Publication Date
June 1, 1982
Publication Information
Publication: Astrophysical Journal Supplement Series
Volume: 49
Subject Category
SOLAR PHYSICS
Funding Number(s)
CONTRACT_GRANT: NASA ORDER S-65013-B
Distribution Limits
Public
Copyright
Other