Results and Analysis of the RHESSI/SAS Observations of the Optical Solar Limb
Abstract
The Solar Aspect System (SAS) of the RHESSI satellite measures the optical solar limb in the red continuum with a cadence typically set at 16 samples/s in each of three linear CCD sensors. RHESSI has observed the Sun continuously now for more than 9 years, and we have acquired a unique data set ranging almost over a full solar cycle and consisting of about 25x109 single data points. These measurements have led to the most accurate oblateness measurement to date, 8.01+-0.14 milli arcsec (Fivian et al., 2008), a value consistent with models predicting an oblateness from surface rotation. An excess oblateness term can be attributed to the enhanced network. New measurements of latitude-dependent brightness variations at the limb lead to a quadrupolar term (a pole-to-equator temperature variation) of 0.04+-0.02 K. We present the analysis of these unique data and an overview of some results.
- Publication:
-
AAS/Solar Physics Division Abstracts #42
- Pub Date:
- May 2011
- Bibcode:
- 2011SPD....42.1724F