Yeah, just tested by putting it out around the neghborhood of Jupiter (those concentric rings should have distance indicators IMO), 12.8 AU to be exact, and it spawned molten.
Sent off a report as well. I think I forgot to include last screenshot, but that's probably ok.
Edit: Found a related bug, Mars doesn't heat up even when ridiculously close to the sun. Theres probably a slew of problems with the heating system.
Edit2: Toggled the 'enable climate', which immediately toggled back off, and then it started heating up. So, the climate sim isn't working too well either.