No abstract

The 15.4-day cepheid AV Sgr has been suggested as a possible member of the open cluster NGC 6546. In order to investigate this possibility, we obtained new spectroscopic, radial velocity, and photometric data at Cerro Tololo Inter-American Observatory. From these data we find a distance to the cluster of 1.20 ± 0.12 kpc, considerable differential reddening with a mean color excess E B _ V = 0.72 ± 0.14 (s.d.), and earliest spectral type ~ B2. This places it on the outer edge of the -I spiral arm. From similar data for AV Sgr we find a distance of 2.20 ± 0.25 kpc and excess E B _ V = 1.37 s.d. ± 0.03, leading us to conclude that it cannot be a member.