The Solar Radius at 37 GHz through Cycles 22 to 24
| Autor: | C. G. Giménez de Castro, Caius L. Selhorst, Adriana Valio, Juha Kallunki, Joaquim E. R. Costa |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Normalization (statistics) 010504 meteorology & atmospheric sciences FOS: Physical sciences Astronomy and Astrophysics Solar radius Astrophysics Solar atmosphere Lambda 01 natural sciences Solar cycle Wavelength Radio observatory Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences Activity cycle 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Popis: | To better understand the influence of the activity cycle on the solar atmosphere, we report the time variation of the radius observed at 37 GHz ($\lambda$=8.1 mm) obtained by the Mets\"ahovi Radio Observatory (MRO) through Solar Cycles 22 to 24 (1989-2015). Almost 5800 maps were analyzed, however, due to instrumental setups changes the data set showed four distinct behaviors, which requested a normalisation process to allow the whole interval analysis. When the whole period was considered, the results showed a positive correlation index of 0.17 between the monthly means of the solar radius at 37 GHz and solar flux obtained at 10.7 cm (F10.7). This correlation index increased to 0.44, when only the data obtained during the last period without instrumental changes were considered (1999-2015). The solar radius correlation with the solar cycle agrees with the previous results obtained at mm/cm wavelengths (17 and 48 GHz), nevertheless, this result is the opposite of that reported at submillimetre wavelengths (212 and 405 GHz). Comment: 11 pages, 5 figures, accepted for publication in Solar Physics |
| Databáze: | OpenAIRE |
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