Hmm, emissive ability on a planet... that's clever! I wonder if it will work... that could be an an alternate way of making glassing a planet harder!
(I_DONT_CARE, emissive ability does not generate additional hitpoints, despite its description in Abilities.txt - it actually reduces the damage of each incoming attack by the specified number of points, so in your case the planet would be immune to anything doing 3000 damage or less, and an attack doing 4000 damage (good luck finding one
) would actually do 1000 damage.)