Ten low-mass companions from the Keck precision velocity survey

Ten new companions have emerged from the Keck precision Doppler velocity survey, with minimum (M sin i) masses ranging from 0.8 M-JUP to 0.34 M.. Five of these are planet candidates with M sin i < 12 M-JUP, two are brown dwarf candidates with M sin i ∼ 30 M-JUP, and three are low-mass stellar companions. Hipparcos astrometry reveals the orbital inclinations and masses for three of the (more massive) companions, and it provides upper limits to the masses for the rest. A new class of extrasolar planet is emerging, characterized by nearly circular orbits and orbital radii greater than 1 AU. The planet HD 4208b appears to be a member of this new class. The mass distribution of extrasolar planets continues to exhibit a rapid rise from 10 M-JUP toward the lowest detectable masses near 1 M-SAT.