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Old 04-17-2006, 08:53 AM   #9
MrId
 
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Join Date: Oct 2005
Location: Boston, MA
Default Re: Space 4e System Generation

Quote:
Originally Posted by dataweaver
I'm also inclined to say that not even epistellar gas giants can exist inside the luminosity-based inner limit. Incidently, this also places a hard upper limit of planetary blackbody temperatures: 2800 Kelvins.
I'm not sure about that -- haven't large gas giants been detected very close to thier primaries in other star systems? I think they can survive there if they formed further out and have sufficient mass to keep their atmosphere despite the increased heating, but I'm decidedly not an astrophysicist.

Quote:
Originally Posted by dataweaver
I'm looking into guidelines for climate variations based on day vs. night, using the Tide-locked world rules as limits. My problem lies in figuring out how long a day can be before the limits are hit. I'm also interested in computing lattitude-based variations; while I know that there ought to be a simple formula for this, I don't know what it would be.
I have largely the same stuff from First In, so I'll just but a couple additional notes in:

Adding to what Pomphis wrote, for latitude based variation, the planets "average" climate zone should be in hex rows 4-5 (on the old icosahedral map), while rows 2-3 will be one categories warmer, while the equator will be two categories warmer. Repeat the same sequence heading towards the poles (6-7 one cooler, 8-9 two cooler, 10-11 three cooler, and 12-13 four cooler). While the book (First In) doesn't say either way, I think that this requires a substantial atmosphere to work and distribute the heat evenly. Of course, if there isn't an atmosphere, the PCs will probably have problems other than the temperature...

For seasonal variation, the only thing that I would add is, according to First In, axial tilts of 40 degrees or more will affect temperature to some degree all the way down the equator, while planets with 25 degrees of tilt would have "full seasonal effects" in rows 7-13, but not so much below that. I found that with First In I generated a lot of planets with high axial tilts, which would probably cause all sorts of headaches for settlers trying to do any sort of agriculture.
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