# Planet's Without-Atmosphere Mean Surface Temperature New Equation: Tmean = [ Φ (1-a) S (β*N*cp)¹∕ ⁴ /4σ ]¹∕ ⁴ (K)

### Io /Enceladus satellite measured mean surface temperatures comparison 110 K / 75 K

Here we have some two, far away from the sun moons, satellite measured mean temperatures comparison.

Io is Jupiter's moon and Enceladus is Saturn's moon.

Both have solar irradiation accepting factor Φ = 1 ( rock type surface, heavy cratered )

Here we have a complete comparison coefficient with all the terms (albedo, solar flux, N and cp) and with all the terms being different.

Io's mean radius is 1.822 km

Enceladus's mean radius is 252,1 ± 0,2 km

Comparison coefficient

[ (1 - a) S (N*cp)¹∕ ⁴ ]¹∕ ⁴

Io

Tmean = 110 K

[ (1- 0,63) 50,37 (0,5559*0,145)¹∕ ⁴ ]¹∕ ⁴ = 1,77518

Tmean = 75 K

[ (1- 0,85) 14,84 (0,7299*1)¹∕ ⁴ ]¹∕ ⁴ = 1,19766

Let's compare

110 K / 75 K = 1,4667

1,77518 /1,19766 = 1,4822

There is only 1% difference!

Conclusion:

Everything is all right.

It is a demonstration of the Planet Surface Rotational Warming Phenomenon!

And

It is the confirmation that the planet axial spin (rotations per day) "N", and the planet average surface specific heat "cp" (cal∕gr*oC) should be considered in the (Tmean) planet mean surface temperature equation in the sixteeth root:

Tmean.planet = [ Φ (1-a) So (1/R²) (β*N*cp)¹∕ ⁴ /4σ ]¹∕ ⁴.