### 10. Rhea’s (Saturn’s satellite) Effective Temperature Calculation

**10. Rhea’s (Saturn’s satellite) Effective Temperature Calculation: **

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

**Rhea’s albedo: arhea = 0,949 (geometric) **

**1/R² = 1/9,04² = 1/81 = 0,01234567 **

**Rhea is a heavy cratered planet, so the Φ = 1 **

**cp.rhea = 1 cal/gr*oC **

**Rhea’s sidereal rotation period is 4,518212 days **

**Rhea performs N = 1/4,518212 rotations /per day, synchronous**

**β = 150 days*gr*oC/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**

** Rhea’s effective temperature Te.rhea is **

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

**Τe.rhea = { 1*(1-0,949)*1.362 W/m² *0.01234*[150*(1/4,518212)*1]¹∕ ⁴ /4*5,67*10⁻⁸ W/m²K⁴ }¹∕ ⁴ **

**Te.rhea = 54,881 K **

**The temperature on Rhea is 99 K (−174 °C) in direct sunlight and between 73 K (−200 °C) and 53 K (−220 °C) in the shade. We don’t have data for the Rhea’s Bond albedo. We have data only for Rhea’s Geometric albedo: arhea = 0,949 (geometric) **

**But such a high albedo doesn’t leave enough sunlight in our formula; therefore the Planet- Without-Atmosphere Effective Temperature Formula is based on the Bond Albedo and not on Geometric Albedo. **

**Tsat.rhea = min 53 K, max 99 K **