"R" == Rich  <someone@somewhere.com> writes:

R> In infinite wisdom Joseph Lazio answered:

We know planets are widespread.  More than 5% or 10% of
solar-type stars have Jupiter-mass planets.  Serious selection
biases against finding lower-mass planets, but from the current
census it appears that there are more lower-mass planets than
Jupiter-mass planets.

R> Which census is this?

Umm, the current one?  By the "current census," I mean the known
extrasolar planets.

R> Almost exclusively gas giants, only a few oddball terrestrial
R> planets.  I don't see how you can derive that there are "more
R> lower-mass planets than Jupiter-mass planets" from the data at
R> hand.

From Marcy et al. (2003, "Properties of Extrasolar Planets," in
_Scientific Frontiers in Research on Extrasolar Planets_,
eds. D. Deming & S. Seager, p. 1)

   The distribution of masses rises rapidly toward the lower masses,
   dN/dM ~ M^{-0.7} ....

Later in the paper, they point out that incompleteness for the lower
mass planets implies that the actual increase is probably even steeper
than M^{-0.7}.

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