Predicted effective temperatures and radii (in units of
Jupiter radii, Rjup~70,000 km) of some extrasolar planets
and brown dwarfs, including reasonable uncertainties for their mass, 
albedo and age. The dashed line is for isolated H-He (Y=0.25)
objects after 10 Ga of evolution. The upper panel also shows
potentially important chemical species expected to condense near
the photosphere in the indicated range of effective temperatures.
(From Guillot 1999; Science 286, 72).