Abstract

The triple star system α Cen AB and Proxima Cen - the component C - is the nearest to the Sun. The study of its dynamics has shown that this system is probably not a chance one. The motion of the component C (Proxima) with respect to the centre of mass of the pair AB is hyperbolic with the probability P=1.0. We observe, therefore, a slow passage of C close to the pair AB. We propose the hypothesis that this system is a part of a stellar moving group. We list the probable members of this group amongst the nearby stars. Amongst them we have the binaries Gliese 140.1 and 676, the triple system ADS 10288 (Gliese 649.1), and six single stars. The probability to find these stars by chance inside the velocity space cube with a side of 20km/s around α Cen is equal to about 2%.