High Resolution Center-To-Limb Variation of the Quiet Solar Spectrum Near Mg II
Abstract
The accurate determination of the high resolution center to limb variation of the solar spectrum is of fundamental importance to our understanding of both spatially resolved solar spectral radiance as well as full disk spectral irradiance. Previous studies have examined the center to limb variation at various spectral resolutions using both observations and calculations. In his study we derive the center to limb variation near Mg II at 2800 A from observations made by the HRTS rocket spectrograph at both high spatial (1-arc second) and spectral (0.077A) resolution. We present the details of the methods used in this derivation including the determination of the vignetting properties of the HRTS instrument. This latter correction accounts for the intensity variation along the slit axis of the observed spectrogram. The resulting center to limb variation is use in a model of solar spectral irradiance near Mg II. Using these results and calibrated solar irradiance spectra the absolute intensity calibration is generated for the HRTS spectra. An important aspect of the high resolution center to limb variation we present is the presence of many spectral features demonstrating the differences between the wings and cores of the numerous Fraunhofer lines in the 2765-2875 A region. In addition, both the Mg I and Mg II lines in this spectral region have very broad smooth wings with significant variation across these spectral features. The results of this study will provide a good source of comparison for detailed models of the solar spectrum.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2008
- Bibcode:
- 2008AGUSMSP21B..02M
- Keywords:
-
- 1616 Climate variability (1635;
- 3305;
- 3309;
- 4215;
- 4513);
- 1650 Solar variability (7537);
- 7507 Chromosphere;
- 7538 Solar irradiance;
- 7549 Ultraviolet emissions