### Neptune’s Effective Temperature Calculation

Neptune’s Effective Temperature Complete Formula Te.neptune is:

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

Neptune’s sidereal rotation period is16 h 6 min 36 sec, or 0,6713 day

N = 1/0,6713 rotations/per day

R = 30,33 AU, 1/R² = 1/30,33² = 0,001087 times lesser is the solar irradiation on Neptune than that on Earth.

So = 1.362 W/m² is Solar constant

Neptune’s albedo, aneptune = 0,290

Neptune is a gaseous planet, Neptune’s surface irradiation accepting factor Φneptune = 1

(Neptune has not surface to reflect the incident sunlight. Accepted by a Gaseous Hemisphere with radius r sunlight is S*Φ*π*r²(1-a), where Φ = 1)

cp.neptune = 3,1388 cal/gr oC , H₂ specific heat at 175 K, Neptune has not surface, Neptune's atmosphere consists from 80% +- 3,2% H₂ and 19%+-3,2% He₂

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

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

So we have

Neptune’s effective temperature Te.neptune is:

Te.neptune = {1*(1-0,290)1.362*0,001087(W/m²) [150*(1/0,6713)*3,1388]¹∕ ⁴ /4*5,67*10⁻⁸(W/m²K⁴) }¹∕ ⁴ =

**Te.neptune = 69,88 K is the calculated.**

And below is the measured by satellites

** Tsat.mean.neptune = 72 K (at 1bar level)**

** Tsat.mean.neptune = 55 K (at 0,1 bar level).**

Let's for comparison reason calculate Neptune’s Effective Temperature Incomplete Formula Te.neptune.incompl is:

Te.neptune.incompl = [ (1-a) So (1/R²) /4σ]¹∕ ⁴

Te.neptune.incompl = [(1-0,290)1.362*0,001087(W/m²) /4*5,67*10⁻⁸(W/m²K⁴) ]¹∕ ⁴ =

Te.neptune.incompl = 46,40 K is the calculated.

And below is the measured by satellites

Tsat.mean.neptune = 72 K (at 1bar level)

Tsat.mean.neptune = 55 K (at 0,1 bar level).

And comparing with the Effective Temperature Complete Formula Te.neptune.compl = 69,88 K we may conclude here that the without-atmosphere Effective Temperature Complete Formula, when applied to Gaseous Giant (Ice Giant) Neptune gives us much closer to the measured by satellites result.

**I**

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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 ← T↓max**