Re: Programming a calendar system

For a planet to have an Earthlike temperature at a distance of 0.7 AU from
their star means that their star must be cooler than the Sun, since they are
receiving the
same amount of radiation from their star as we are at a larger distance.
G-type stars like the Sun have surface temperatures around 6000 K, and
K-type stars (the next coolest) have surface temperatures around 4500 K.
They are also rather larger than the Sun, with diameters around 30 Sol.
Their average densities are
slightly lower so a mass of 1.6 Sol could well be OK. Brightness is a far
from straightforward issue. The term you want is "absolute magnitude" which
is a guide
to the real brightness of a star. After all, the Sun only appears as bright
as it does because we're so close to it - if you went to alpha Centauri (4.3
lightyears)
the Sun would appear as a bright "night-time" star; if you went to Castor
(45 lightyears) the Sun would just be visible with the naked eye. Your best
bet is to put
the term "Hertzsprung-Russell diagram" into a search engine. This is a type
of graph which shows how temperature, brightness, etc. are related. Good
luck!
Mike
 ----- Original Message -----
From: "James Worlton" <JWorlton@...>
To: <CONLANG@...>
Sent: Thursday, April 29, 2004 4:04 PM
Subject: Re: Programming a calendar system


> >each.  That's a total of 19,137,124.8 SI seconds, which is about 221.5
> >Earth days, which is about 0.6064 Earth year.  So the planet of the
> >Aregans must be 0.6064^2^(1/3) = 0.5325 AU from their Sun.
>
>
> >That means
> >that their Sun has to be a K-type (red) star.   Which means that their
> >Sun is much bigger than ours as well as much closer to them, so would
> >be much more dominant in the daytime sky.
>
> Cool. Do you have a good source for this type of data? My conculture/
> conworld needs some astronomical legitimacy, and this looks like a good
> way to create it. I figure that the star of the culture is say 1.6 solar
masses.
> So how do I find out the characteristics of it? That is, brightness,
color,
> temperature, where the life zone is, etc.
>