A SEARCH FOR RADIO-EMISSION FROM THE NONMAGNETIC CHEMICALLY PECULIAR STARS

We have observed 23 members of the Am and HgMn subclasses of chemicall y peculiar (CP) stars with the VLA to search for nonthermal radio emis sion at levels comparable to those found for the Si and He peculiar su bclasses of the CP stars by Linsky et al. [ApJ, 393, 341 (1992)]. This study was motivated by recent claims that magnetic fields of kilogaus s strength are present in at least some of the Am and HgMn stars, cont rary to previous beliefs, which would indicate that radio-emitting mag netospheres could be present in these stars. We detected none of the A m and HgMn stars as radio emitters with upper limits typically < 0.20 mJy. Applying a correlation between radio luminosity, surface magnetic field, and effective temperature derived from previous radio studies of the Si and He peculiar CP stars, we find that the predicted radio l uminosities of alpha And (an HgMn star) and Sirius (a hot Am star) are more than an order of magnitude larger than the observed upper limits , indicating that these stars lack magnetospheres, and, by inference, surface magnetic fields.