Magnetic Modulation of Solar Luminosity by Photospheric Activity
Abstract
The authors study the behavior of slow changes in solar irradiance, S, using measurements obtained with radiometers on the SMM and Nimbus 7 spacecraft. The analysis of the 1978 - 1984 ACRIM and ERB radiometry reveals low-amplitude (0.04% - 0.07%) variations in S on time scales of 4 - 9 months that are well correlated between these two data bases. The variations correlate very well with changes in facular radiations. It is also shown that the slow downtrend in S seen since 1981 by the ACRIM and ERB arises mainly from a decreasing irradiance contribution of bright photospheric magnetic elements outside the large faculae included in the daily CaK plage index. The finding that this network contribution is unbalanced over several years shows that photospheric activity has a net influence on solar luminosity, besides the more nearly balanced contributions of the spots and the large faculae.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1988
- DOI:
- 10.1086/166297
- Bibcode:
- 1988ApJ...328..347F
- Keywords:
-
- Magnetic Effects;
- Photosphere;
- Solar Activity;
- Stellar Luminosity;
- Faculae;
- Modulation;
- Nimbus 7 Satellite;
- Solar Magnetic Field;
- Solar Maximum Mission;
- Solar Physics;
- EARTH: GENERAL;
- SUN: ACTIVITY;
- SUN: FACULAE;
- SUN: GENERAL;
- SUN: MAGNETIC FIELDS