-=> Quoting Charles Daniels to Jack Sargeant <=-
 > ...But are the stars of a group that could have planets capable of
 > supporting life as we know it?  They would have to be of the G-2
 > class.
 CD> As I recall Sol is a G-4 star.  
     Jack's right.  It's a G-2.  
 CD> I don't see why a class M or K star
 CD> couldn't support life if the planets were closer, or why a B star
 CD> couldn't if the planet was further away.  Each star would have it's
 CD> own "life zone" where a planet could exist that could provide it
 CD> with earth-like conditions.
     Kinda sorta almost but not quite.
     A number of factors come into play here - total radiation, 
age, orbital parameters, etc - but the most likely candidates are 
the F and G class stars ... maybe K-0 as well.  For each class, 
there is a band in which a LAWKI (Life As We Know It for the 
abbreviation-impaired ) world may exist, and that world would 
have to exhibit parameters (size, mass, orbital diameter, 
material content percentages, et al) which fall within a narrow 
range.  This has the rather nice effect of reducing the size of 
the haystack in which we would have to look for a LAWKI-bearing 
world.
     However, life is a rather persistent bugger, and LAWKI may 
not be a universal constant but rather a local ordinance.  While 
our knowledge of biology is a good first best guess, it may not 
be the only game in town, which opens up other possibilities and 
makes the haystack big again.
Michael
... "Earth.  Mostly harmless." - Douglas Adams
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