The Solar X-ray Limb III

Introduction

How big is the Sun? This question has to be answered with "it depends". The IAU nominal value for the solar radius is given as 695.7 km Prsa et al. 2016. This value is based on optical measurements and depends on details of the atmosphere and radiative transfer models. In two previous nuggets we described a new technique that uses RHESSI visibilities to measure the height of the X-ray limb (The X-ray Limb) and reported on preliminary analysis of a suitable solar flare (The Solar X-ray Limb II). As reported in the second nugget there were some problems with the chosen flare, but having found a better suited candidate we can finally claim success!