INDEPENDENT DISTANCE DETERMINATIONS TO MILKY-WAY CEPHEIDS IN OPEN CLUSTERS AND ASSOCIATIONS .3. CV-MON IN ANON-VANDENBERGH

As part of a program aimed at comparing the galactic Cepheid distance scales from cluster ZAMS fitting and from independent Baade-Wesselink techniques, we have used new, high-quality light and radial velocity c urves of the Cepheid CV Mon supposed to be a member of the sparse clus ter Anon van den Bergh to obtain its distance and mean radius from the visual surface brightness method, We find the distance to CV Mon to b e 2160+/-200 pc which is similar to 20% larger than the ZAMS-fitting d istance to the cluster determined by Turner [JRASC, 72, 248 (1978)] bu t cluster membership of CV Mon is still possible given the uncertainti es of both determinations. Our surface brightness analysis yields a me an radius of 53.5+/-3.9 R. for CV Mon. The Cepheid's absolute visual m agnitude is -3.67+/-0.36 mag, whose large uncertainty is dominated by the relatively uncertain absorption correction. Use of near infrared p hotometry would reduce the uncertainty in the absolute magnitude. We f ind rather clear evidence that CV Mon is pulsating in the fundamental radial mode. There is no evidence, neither from the existing photometr y nor from radial velocity observations obtained over eleven years, th at there is a binary companion to the Cepheid. (C) 1996 American Astro nomical Society.