[TML] Habitable Zones

[Garry Ward]

----- Original Message ----- 
From: "Tim Rattray" <tim.rattray at gmail.com>
To: "The Traveller Mailing List" <tml at travellercentral.com>
Sent: Friday, November 09, 2007 8:27 AM
Subject: Re: [TML] Habitable Zones


> Ahh, found it.
>
>  L = 4 $B&P(B r^2 $B&R(B T^4
>
> where L is the star's luminosity, r is the distance from the center of
> the star, $B&R(B is the Stefan-Boltzmann constant (= 5.67 $B!_(B 10^ -8 W m-2
> K-1), and T is the effective temperature (in Kelvin)
>
> So solve for r gives us
>
> r^2 = L / 4 $B&P(B $B&R(B T^4  or r = SQRT(L / 4 $B&P(B $B&R(B T^4)
> Now do two calcs, one with T = 373K (inner HZ) and one with T = 273K 
> (outer HZ)
>
>
> Question is, what is L measured in?  (r is in meters)
Interesting, your post got to my machine demanding a japaneses character set 
be installed...

Anyway,

Luminosity is the total energy output of the star.

Stephen Gillette's World Building book that I have defines it as being solar 
luminosities (Our sun = 1) and it can be derived from the magnitude of the 
star ( L = 2.52 ^ (4.85 - the target star's absolute magnitude))

Garry
>
> Tim
>


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