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On Sunspot and Facular Contrast Variations Near 2 μm and 4 μm

Published online by Cambridge University Press:  03 August 2017

V. A. Kotov  and
S. Koutchmy
V. A. Kotov
Affiliation:
CSSA, Stanford University, Stanford, CA 94305, U.S.A. Crimean Astrophysical Observatory, Nauchny, Crimea 334413, USSR
S. Koutchmy
Affiliation:
Institut d'Astrophysique, CNRS, 98 bis, Boulevard Arago, F-75014 Paris, France

Abstract

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Observations of the Sun at 2.2 and 3.75 μm have been made at the Pic-du-Midi and Crimean observatories. High resolution (~ 1″) records of the sunspot and facular contrasts at various heliocentric distances as well as those at the extreme solar limb are presented. We find substantial variations in the sunspot-core relative intensity caused by magnetic activity of the spot. The extreme-limb contrasts of faculae at 3.75 μm are strong thus support flux-tube models which result in an enhancement of the extreme-limb facular brightness.

Keywords

flux tubesinfrared: starsSun: faculae, plagessunspots
Type
Part 3: Infrared Perspectives on Atmospheric Dynamics
Information
Symposium - International Astronomical Union , Volume 154: Infrared Solar Physics , 1994 , pp. 265 - 270
Copyright
Copyright © Kluwer 1994 

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