From: menarson@cox.net   
      
   "Logan Kearsley"  wrote in message   
   news:94Lue.5451$G4.4772@trnddc09...   
   > Can anybody tell me or point me to a source for formulas for the main   
   > sequence lifetime and luminosity change with age given a star's mass?   
   >   
   > The usually-quoted and easily found main sequence lifetime equation   
   > t=1/M^2.5 is horribly inaccurate according to all of the tables I have   
   > found   
   > listing Mass vs. Lifetime.   
   > .   
   > .   
   > .   
      
   Logan, you might want to check out the "Ask Astro" column of the Sept. 05   
   issue of Astronomy magazine.  There was a question of how long a red or   
   brown dwarf will "live".  You don't only have to take into account the   
   amount of hydrogen, how hot it burns which determines the nuclear reactions,   
   but also the amount of convective mixing which determines the amount of   
   hydrogen the star will be able to burn up.   
      
   BTW I did not realize their was an equation of longevity based on a star's   
   mass.  It would seem that it would be off to a fair amount (as you found)   
   because of the different factors that account for how long a star will last.   
      
   Regards   
   Mike   
      
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