Temperature in Celestia 1.6.1

General discussion about Celestia that doesn't fit into other forums.
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gironde M
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Temperature in Celestia 1.6.1

Post #1by gironde » 13.10.2018, 10:05

Please, would anyone know how is the temperature of planets or other objects calculated in Celestia 1.6.1?

My goal is to frame the calculation of this temperature in LUT5.
In Celestia, the Sun's temperature is provided by the CELX function obj: getinfo (). Temperature.

In Celestia 1.6.1 this value is 5860 K
In Celestia EPV3 (1.7.0 v5229) this value is 5780 K

To determine the surface temperature of a planet, a moon, ... we need a formula that is a function of the temperature of the star, the distance from the body to the star, the albedo,. ..

What is this formula in Celestia?

:hi:

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Post #2by onetwothree » 13.10.2018, 15:25

BodyTemperature = StarTemperature * ((1.0 - BodyAlbedo) ** 0.25) * sqrt(StarRadius / (2.0 * BodyDistanceFromStar)))

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Post #3by Croc » 13.10.2018, 18:25

BodyTemperature = StarTemperature * ((1.0 - BodyAlbedo) ** 0.25) * sqrt(StarRadius / (2.0 * BodyDistanceFromStar)))

formula-1.jpg


formula-2.jpg


StarTemperature = 5860
BodyAlbedo = 0,37
StarRadius = 696000
BodyDistanceFromStar = 149600000

(1.0 - BodyAlbedo) ** 0.25 = 0,890912674
sqrt(StarRadius / (2.0 * BodyDistanceFromStar)) = 0,048230729
BodyTemperature = 251,8004945 :smile:

onetwothree :clap:

onetwothree, please indicate the source of information.
Creator of the GUI "Lua Universal Tools"
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Post #4by gironde » 14.10.2018, 07:17

The site http://planet-terre.ens-lyon.fr/article/temperature-de-surface.xml
provides this formula for the solar system:
280* [ (1-bodyalbedo) / (BodyDistanceFromStar)^2 ]^0.25
It does not say what 280 represents
for this formula to work outside the solar system, I thought of:
(Tstar/Tsol) * formula

with Croc values, the result for the Earth is 256 K (-17°C), Venus 227K (-46°C), Mercury 404K (131°C)

Thank 'onetwothree', but is this the formula used internally in Celestia 1.6.1

:smile: :hi:

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Post #5by onetwothree » 14.10.2018, 08:45

Croc wrote:onetwothree, please indicate the source of information.

I took it from celestia sources. But you can find it here.

gironde wrote:Thank 'onetwothree', but is this the formula used internally in Celestia 1.6.1
yes, see here.

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Post #6by Croc » 14.10.2018, 09:11

#5by onetwothree
...................
I took it from celestia sources. But you can find it here.

onetwothree, thank :smile:
Creator of the GUI "Lua Universal Tools"
25/V/1947 - 30/III/2019

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Post #7by gironde » 14.10.2018, 16:55

And for me too, thank you 'onetwothree'


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