Preliminary results are given for a systematic survey of K-dwarf stars in the solar vicinity. Nine companions to the G and K dwarfs have very low M
2 sin i, less than 0.08 M
⊙. These detections from a sample of 540 G and K primary stars support the reality of the existence of companions with mass below 0.08 M
⊙: brown dwarfs exist.
A comparison of the relative mass function distribution f(m)/M
1 between low-mass (M
1 < 1.3 M
⊙) and intermediate-mass (2 < M
1 < 5 M
⊙) binaries suggests a dependence of the mass-ratio distribution on the mass of the primary: f(q, M
By combining the photometric information with orbital elements constraints, we have derived the mass-ratio distribution for intermediate-mass stars. As is the case for low-mass stars, this distribution does not have any maximum close to M
1 = 1.