On Mon, Oct 17, 2016 at 05:00:54AM -0400, Jerry Barrington wrote:
> Regarding planets around a dim star (or technically *any* multiple
> system): GM should calculate the blackbody temperature of each
> planet by summing 278*(L^.25)/(R^.5) for all stars.

Actually they should sum L/R^2, take the fourth root of the sum, and
multiply by ~278 K.  In most cases this will be very similar to just
taking the maximum (though always at least slightly greater).

A comparative example: suppose a planet orbits a cool M-class star
with luminosity 0.05 at 0.4 AU, which in turn orbits a bright star
with luminosity 2 at distance 1.6 AU.

Maximum method: planet has temp 260 K.
Quoted method (summing temperatures): planet has temp 470 K.
Summing then taking fourth roots: 284 K.

- Tim