The orbit of the nearby low-mass binary Gliese 600

We have computed a combined spectroscopic-interferometric orbit for the nea rby binary Gliese 600 discovered by us. The orbital period is 2.78 years, a nd the semimajor axis is 100 mas (0.1 "). Its M0V components are almost ide ntical and have a mass of 0.5M.. The mass ratio is uncertain because of the low radial-velocity semiamplitude (7 km s(-1)) associated with the low orb ital inclination (37 degrees): The orbital parallax of the binary (52 +/- 1 1 mas) matches its dynamical and photometric parallaxes but differs signifi cantly from the Hipparcos parallax (44.3 +/- 1.6) mas; the latter was proba bly distorted by the orbital motion that was not taken into account. (C) 20 00 MAIK "Nauka/Interperiodica".