Abstract
NUMEROUS attempts have been made to find the physical mechanism responsible for the sunspot cycle. Present theoretical discussions of the basic mechanism of solar activity are usually based on a dynamo theory with a reversing magnetic field1, but objections and alternative interpretations1,2 have recently been advanced. Our understanding of the sunspot cycle seems to be in a stage where new observational insight may be valuable. We report here a variation in the infrared umbra intensity of large sunspots with the phase in the solar cycle.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to the full article PDF.
USD 39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Bumba, V. & Kleczek, J. Basic Mechanisms of Solar Activity, I.A.U. Symp. 71 (Reidel, Dordrecht, 1976).
Gokhale, M. H. Kodaikanal Obs. Bull. A 2, 10–27 (1977).
Ekmann, G. & Maltby, P. Solar Phys. 35, 317–322 (1974).
Iuell, P. & Staveland, L. Inst. theor. Astrophys. Rep. No. 43 (Oslo, 1975).
Ekmann, G. Solar Phys. 38, 73–75 (1974).
Maltby, P. Solar Phys. 55, 335–346 (1977).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
ALBREGTSEN, F., MALTBY, P. New light on sunspot darkness and the solar cycle. Nature 274, 41–42 (1978). https://doi.org/10.1038/274041a0
Received:
Accepted:
Published:
Issue date:
DOI: https://doi.org/10.1038/274041a0
This article is cited by
-
Structural Invariance of Sunspot Umbrae over the Solar Cycle: 1993 – 2004
Solar Physics (2010)
-
Modeling the Subsurface Structure of Sunspots
Solar Physics (2010)
-
Starspots
The Astronomy and Astrophysics Review (2009)
-
Intensity and Magnetic Field Distribution of Sunspots
Solar Physics (2008)
-
The Behavior of Sunspot Contrast during Cycle 23
Solar Physics (2008)
