HD 209458b Parameters

Orbit
Period		3.52474 days
Semimajor Axis	0.045 AU = 6.75 Mkm
Eccentricity	0.01 +/- 0.03
Inclination	86.7 deg

Planet
Mass		0.69 Mjup
Radius		1.35 Rjup = 96,500 km
Density		0.35 g/cm^3
Surf. gravity	9.43 m/s^2
Escape velocity	43 km/s

Theory says...
Temperature	1500K

Therefore
Scale height	750 km!  (T/g = 30x Jupiter's)