Spectrophotometric studies of Am stars

Abstract

The relationships among the various physical parameters, namely the effective temperatures, radii and bolometric magnitudes, determined on the basis of the energy distribution curves of 25 Am stars are investigated. The ranges are as follows: effective temperature, 7200-9700 K; radii, 1.5-2.5 solar radii; bolometric magnitudes, 0.75-2.25 mag; and mass, 1.5-2.25 solar masses. The Am stars in general are seen as redder than their normal counterparts, the blanketing in the blue and UV regions being the major cause. For the relatively cooler stars, the (B-V) colors are found to be less influenced by blanketing. Located in the neighborhood of the upper edge of the zero-age main sequence band, they exhibit a fairly wide range in the evolutionary status among themselves. The bolometric corrections that are independent of the uncertainties in the parallax measurements follow the same trend as that of the Ap stars with regard to temperature.