Faculae and the solar oblateness - A summary

Abstract

Dicke and Goldenberg (1967) inferred a value of the solar oblateness by projecting an image of the sun on a circular occulting disk and measuring the light flux from the portion of the sun exposed beyond the disk. These measurements have the implication that if the optical oblateness measured is mirrored in a true gravitational oblateness, then the non-Newtonian part of Mercury's perihelion advance cannot agree with Einstein's prediction based on general relativity. The present analysis shows that faculae may have contributed all of Dicke and Goldenberg's excess signal. There is overwhelming evidence that this signal is contaminated by faculae at some level, and very little evidence to exclude faculae as a cause of the signal.