[email removed] (james vassilakos) writes:
Re: Star types
but type O, I'm not sure why they changed it... probably in order
to conform more closely with observed stellar frequencies.
Type O is *very* rare. There's a second factor as well. Type O stars have only a few *million* years on the mainsequence, after which they die rather messily (can *you* say "Supernova"? I knew you could!)
Since all the stars in an area will tend to be of the same age, that means that all the type O (and almost all type B) stars will have gone supernova before life evolved on most planets around here.
Good thing, too. A supernova can be lethal at *interstellar* distances. Several parsecs at least.
Everything I've ever heard regarding planetary formation indicates that a type O star *can't* have them. Too little matter left over from forming the star, and too little time before it got bright enough for the stellar wind and sheer *light pressure* to blast everything out of the system.
It is interesting to note that Space Master (unlike Traveller and
GURPS), includes two other spectral classes (S and N), which are
placed below M (dim red) on the classification scheme. Actually,
to the best of my understanding, there are 10 spectral classes:
O, B, A, F, G, K, M, R, N, and S.
Are there any astronomer types out there who can tell us
more about these final three spectral types and/or give us some
local-area frequency probabilities for each of the spectral
types?
I'm only an amateur, but I've got a textbook sitting in fromt of me. It doesn't even *list* R, N, and S types. From my reading, I seem to recall that they are very rare and don't really fit in with the other tpyes. For the sort of thing we are talking about, they *should* be ignored.
So type O stars should be *at most* one per campaign (unless your campaign map covers *thousands* of parsecs) and they shouldn't have planets.
BTW, if the tables give (as I recall) stellar luminosity on a scale that has Sol as 1 and a type O star at 10,000 or so, then there's a rough formula for how long the star will spend on the main sequence:
T=11*(L^.75)
T= lifetime in billions of years
L= luminosity
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