re: Astrometric versus Doppler wobble
Mpsin(i) is, therefore, the minimum mass of the planet
That is why Marcy & Butler, et. al. all qualify their results. At first many skeptics suspected that the "planets" were really massive Brown dwarfs, but in orbits inclined at a high angle to our ecliptic. Later observations statistically made this improbable. To this day, we only KNOW the minimum mass not the actual mass of most of these extrasolar planets.
I'm very encouraged by the promise of astrometry in these posts.