Spatial and temporal variations in the solar brightness
- Creators
- Woodard, M. F.
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Libbrecht, K. G.
Abstract
We have investigated long-term variations of solar brightness as a function of both time and solar latitude using eight years of ground-based photometric data in conjunction with space-based irradiance data. In particular, we have examined whether the combination of sunspot brightness deficits and facular brightness excesses is sufficient to explain the solar cycle irradiance variations. After correcting for the contribution from sunspots, we find that the irradiance data can be adequately explained by a model in which the remaining brightness variations are due entirely to facular contributions confined to the magnetically active latitudes. Thus we find no support for the hypothesis that there are convectively driven hot bands in the active latitudes, and our data show brightness variations that are well described by a facular contrast function.
Additional Information
© Kluwer Academic Publishers 2003. (Received 11 April 2002; accepted 12 September 2002) This work was supported by grants from the NSF and NASA. The BBSO observations were carried out over several years by Bill Marquette, Randy Fear, Jeff Nenow, John Varsik, and others. Unpublished data from the VIRGO Experiment on the cooperative ESA/NASAMission SOHO (data composite_d19.asc) were obtained from PMOD/WRC, Davos, Switzerland (Fröhlich and Lean 1998). ACRIM composite data (composite_na3.htm) obtained from http://www.acrim.com. Data from Lean et al., (1998) were kindly supplied by J. Lean.Additional details
- Eprint ID
- 98526
- Resolver ID
- CaltechAUTHORS:20190909-133031536
- NSF
- NASA
- Created
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2019-09-09Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field