SIMBAD references

This paper reports on the spectroscopic investigation of 54 Cepheids, deriving parameters and abundances. These Cepheids extend previous samples by about 35% in number and increase the amount of the Galactic disk coverage, especially in the direction of l~120°. We find that there exists in the Galactic disk at that longitude and at a solar distance of about 3-4 kpc a region that has enhanced abundances, <Fe/H]>~+0.2, with respect to the local region. A simple linear fit to all Cepheid data now extant yields a gradient d[Fe/H]/dR_G=-0.068±0.003 dex.kpc^–1. After consideration of the spatial abundance inhomogeneities in the sample, we conclude that the best current estimate of the overall gradient is d[Fe/H]/dR_G=-0.06 dex.kpc^–1.