Thanks for the link. I wonder what temperature prevails at 1.0 AU.

On the one hand, artists’ conceptions of boiled oceans and cities in cinders that saddened and discouraged me in my childhood. On the other hand, the heat energy density of Sol today is comparable to a compost heap. When the radius of a sphere doubles, it’s volume increase eight times.

If Sol is too itsy to start helium fusion, maybe orbiting within the post-expansion photosphere - the hydrogen envelope - is chill, damp, and sparky?