Title: Relationship between solar activity and luminosity
Abstract: Measurements of the solar constant — the total irradiance at mean Sun-Earth distance — during the last 12 years from satellites show variations over time scales from minutes to years and decades. The most important variance is in the range from days to several months and is related to the photospheric features of solar activity: decreasing the irradiance during the appearance of sunspots, and increasing it by faculae and the bright magnetic network. Modulation by the 11-year activity cycle is now observed conclusively with the irradiance being higher during solar maximum. All these variations can be explained - at least qualitatively - by their manifestation on the photosphere. Whether the short term variations are luminosity changes cannot be deduced from irradiance observations. For the solar cycle variation the situation is different: simultaneous changes of the solar p-mode frequencies are observed and both effects can be explained qualitatively by the same mechanism. This suggests that the solar cycle related irradiance change can be interpreted as a global phenomenon and is the manifestation of a change in luminosity. Longer term variations can be inferred from stellar observations and the possibility for a solar origin of the little ice-age during the Maunder minimum are explored.
Publication Year: 1993
Publication Date: 1993-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 5
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