XPost: sci.astro.amateur   
   From: henry@spsystems.net   
      
   In article <1118819258.136624.199020@g44g2000cwa.googlegroups.com>,   
     wrote:   
   >Out of curiousity in regards to the search for Extrasolar planets, why   
   >are planet hunters studying worlds hundreds of light years away when we   
   >have several star systems in our own back yard that don't seem to get   
   >much attention, and in theory wouldn't their closer proximity make them   
   >easier to search for and study possible planets?   
      
   The major method currently used for planet searches, Doppler velocity   
   measurement, does not care very much about distance -- it does *not* work   
   substantially better on very close stars.  It does prefer bright stars,   
   because high-resolution spectroscopy needs quite a bit of light, but the   
   brighter stars mostly aren't close.   
      
   Moreover, Doppler planet detection isn't as easy for multiple stars (Alpha   
   Centauri and Sirius, for example, are both binary).  It's still possible,   
   but harder to do.   
      
   Moreover moreover, it is a relatively slow method except when big planets   
   are very close to the star.  You have to wait multiple orbital periods of   
   the planet to be sure that an apparent planet is real.  So it rewards   
   people who gather data on *many* stars rather than targeting a few   
   specific ones, because that gives a steady stream of discoveries.  Since   
   most of the stars the method is usable on are relatively distant, it's not   
   surprising that you don't hear about nearby stars much.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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