We have carried out an L ^ { \prime } and M band Adaptive Optics ( AO ) extrasolar planet imaging survey of 54 nearby , sunlike stars using the Clio camera at the MMT .
Our survey concentrates more strongly than all others to date on very nearby F , G , and K stars , in that we have prioritized proximity higher than youth .
Our survey is also the first to include extensive observations in the M band , which supplemented the primary L ^ { \prime } observations .
These longer wavelength bands are most useful for very nearby systems in which low temperature planets with red IR colors ( i.e . H - L ^ { \prime } , H - M ) could be detected .
The survey detected no planets , but set interesting limits on planets and brown dwarfs in the star systems we investigated .
We have interpreted our null result by means of extensive Monte Carlo simulations , and constrained the distributions of extrasolar planets in mass M and semimajor axis a .
If planets are distributed according to a power law with dN \propto M ^ { \alpha } a ^ { \beta } dMda , normalized to be consistent with radial velocity statistics , we find that a distribution with \alpha = -1.1 and \beta = -0.46 , truncated at 110 AU , is ruled out at the 90 % confidence level .
These particular values of \alpha and \beta are significant because they represent the most planet-rich case consistent with current statistics from radial velocity observations .
With 90 % confidence no more than 8.1 % of stars like those in our survey have systems with three widely spaced , massive planets like the A-star HR 8799 .
Our observations show that giant planets in long-period orbits around sun-like stars are rare , confirming the results of shorter-wavelength surveys , and increasing the robustness of the conclusion .