The Planet's Effective Temperature and the Planet's Mean Surface Temperature Equation: Tmean = [ Φ (1-a) S (β*N*cp)¹∕ ⁴ /4σ ]¹∕ ⁴

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Charon in enhanced color to bring out differences in surface composition.

Charon in true color, imaged by New Horizons

Charon’s (Pluto’s moon) Mean Surface Temperature Calculation

So = 1.362 W/m² (So is the Solar constant)

Charon’s albedo: acharon = 0,2 to 0,5 at solar phase angle of 15°

let's have acharon = 0,2

1/R² = 1/39,48² = 1/1.558 = 0,0006418

Charon’s sidereal rotation period is 6,38723 days

Charon does N = 1/6,38723 rotations/ per day

Charon is an ice crust planet, very cratered, and Charon’s surface irradiation accepting factor Φcharon =1.

Charon’s surface is composed of water ice

Charon can be considered as a water ice crust surface planet,

cp.charon = 1 cal/gr*°C

β = 150 days*gr*°C /rotation*cal – it is the Planet Surface Solar Irradiation Absorbing-Emitting Universal Law constant

σ = 5,67*10⁻⁸ W/m²K⁴, a Stefan-Boltzmann constant

Charon’s mean surface temperature equation Tmean.charon is:

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

Τmean.charon = { 1*(1-0,20)*1.362 W/m² *0,0006418*[150 *(1/6,38723)* 1]¹∕ ⁴ /4*5,67*10⁻⁸ W/m²K⁴ }¹∕ ⁴ = 51,04 K

Tmean.charon = 51,04 K

Tsat.charon = 53 K (- 220 °C).

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  The faster a planet rotates (n2>n1) the higher is the planet’s average (mean) temperature T↑mean:

Tmin→ T↑mean ← Tmax

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