THE MASS-DISTRIBUTION OF EXTRASOLAR PLANET CANDIDATES AND SPECTROSCOPIC BINARY LOW-MASS COMPANIONS

Spectroscopic orbits have been reported for nine unseen companions orb iting solar-type stars with minimum possible masses in the range 0.5-1 0 Jupiter masses. We compare the mass distribution of these nine plane t candidates with the distribution of low-mass secondaries in spectros copic binaries. Although we still have only a very small number of sys tems, the two distributions suggest two distinctive populations. The t ransition region between the two populations might be at the range of 10-30 Jupiter masses.