I've finally done some more Blender work, inspired by the purchase of a course of tutorials, all about space. See Space VFX by creative shrimp.
The following outputs were produced after watching and mostly following the first tutorial on how to create a simple planet.
I made a few changes to the workflow which I thought would improve things, only to have my changes derail the tutorial about half way through. I considered the results still good enough to keep --- they incorporate some really clever touches that I would never have worked out for myself.
The planet texture consists of two ground maps supported by a third masking layer map.