Expanding Atmosphere Types

[dmm]

Check out the references of that Wiki article, esp. 38, 39, and 43.

There are 2 cases: Planets orbit one star of the pair (S type) or orbit the center of mass of both stars (P type).

S type: If the stars are closer than about 7 AU, then planetary formation is severely compromised. Note that most binaries have separations similar to the distance from the Sun to Neptune (~30 AU).

P type: (This is the type currently depicted in SE.) For this type, you need stars closer than about 0.2 AU or so, plus the eccentricity of their mutual orbits has to be close to zero. Otherwise, again, planetary formation is severely compromised. But at this distance, they are close enough to steal matter from each other as they form. So one companion almost always ends up significantly more massive than the other, and you wind up with a red giant / white dwarf combo. I admit, though, that I don't know how long this would take. It might take a long time. So I take back my original criticism. It's not (obviously) silly to have several main sequence stars in a close binary or trinary.

There's another important point. Although 0.2 AU sounds small, the Sun's diameter is only a bit less than 0.01 AU. I was rather shocked at that info. It turns out that SEIV depicts star+planet systems more accurately than SEV, in which the stars are shown WAY too big. Perhaps a "realism mod" for SEV should greatly reduce the sizes of main sequence stars. (Of course the planets are ridiculously large, but that's just a graphical depiction. Regardless of the planet size, it only takes up one hex.) Alternatively, the star size shown could be taken to be the diameter inside of which ships burn to a crisp. So the star isn't actually that large, but the non-navigable region is. Unfortunately, this is always the same distance regardless of the empire's tech level. A better way would be to make the star much smaller but surround it with rings of damaging storms that diminish in intensity as you get further from the star. Then high tech ships could take short cuts and use hiding places unavailable to low tech ships.

[Phoenix-D]

The stars are only too large if you have a fixed scale in mind for the hexes. Though I agree the current size would be best left to very large stars.

[JAFisher44]

I think that in SEV both stars and planets are inflated in size for "graphical depiction"

If you suppose that the entire system map encompasses say orbit of Pluto, that means that the system map is about 50 AU from center to edge. This gives you a rough distance of about 4 AU per hex. At .01 AU a star would be 1/400th of a hex across. Even if you reduce the map to 1 AU per hex a star will still only be 1/100 of a hex across. Either way, it will be as small as the stars in the background if you want to display it realistically.

[Randallw]

It would be good if temperature, gravity and radiation actually meant something or at least matched the planet. In one game I colonised a huge breathable planet and as we are RP'ing I wrote a story about it. Unfortunately although this supposed optimal world had radiation I could figure out, apparently less than earth, and gravity not too different from 1G it had a temperature of 300 degrees. Call that habitable, I don't. I gave up bothering to mention temperature. It's particularly annoying as it is a glaring difference from the picture.