On the orbital period of 70 Ophiuchi

Abstract

Comparison of two extensive series of determinations of the radial velocity of the brighter component of the visual binary 70 Ophiuchi, one made at the Lick Observatory between 1897 and 1932 and the other at the Dominion Astrophysical Observatory between 1966 and 1990, leads to the establishment of a systematic difference between them of about 0.3 km/s and a most probable value for the orbital period of 88.05 y + or - 0.70 y. This value agrees well with that obtained from observations of separation and position angle, of which it is completely independent. Revised orbital elements, based on the spectroscopic observations alone, are also presented.