The derived equilibrium temperature balanced starlight alone. For the widest orbits that is less
than the 2.7 K every body in space is held at by the cosmic microwave background. The planet 7 493
AU from 2MASS J21252752-8138278 read "Equilibrium temp. 1 K", and the one 19 000 AU out from UCAC4
328-061594 would have read 0 K.
equilibriumTemperatureK now adds the background as a second source in the same balance, T^4 =
T_star^4 + (2.7255 K)^4 (Fixsen 2009). Inside a few hundred AU of any star it changes nothing that
shows: Earth, Mars, Jupiter and Neptune reproduce their published values as before. Across the
6 354 exoplanets, the rounded temperature changes for 11, all on orbits of 350 AU or more. Ten go
from 0, 1 or 2 K to 3 K, from VHS J125601.92-125723.9 b at 350 AU to UCAC4 328-061594 b at 19 000
AU, and 2MASS J22501512+2325342 b at 518 AU goes from 4 to 5 K. On the dev server, the detail
pages of the 7 493 AU planet and of GJ 900 b read "Equilibrium temp. 3 K".
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
SenrokaiandClaude Opus 5.5
b46c840369