A Search for Radio Emission From the "Nonmagnetic" Chemically Peculiar Stars
Abstract
We have observed 23 members of the Am and HgMn subclasses of chemically peculiar (CP) stars with the Very Large Array (VLA) to search for nonthermal radio emission at levels comparable to those found for the Si and He peculiar subclasses of the CP stars by Linsky et al. (1992). This study was motivated by recent claims that magnetic fields of kilogauss strength are present in at least some of the Am and HgMn stars, contrary to previous beliefs, which would indicate that radio-emitting magnetospheres could be present in these stars. We detected none of the Am and HgMn stars as radio emitters with upper limits typically less than 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 luminosities 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.
- Publication:
-
The Astronomical Journal
- Pub Date:
- December 1994
- DOI:
- 10.1086/117231
- Bibcode:
- 1994AJ....108.2203D
- Keywords:
-
- Peculiar Stars;
- Radio Astronomy;
- Radio Emission;
- Stellar Luminosity;
- Stellar Magnetic Fields;
- Stellar Magnetospheres;
- Correlation;
- Data Processing;
- Helium;
- Silicon;
- Stellar Temperature;
- Very Large Array (Vla);
- Astronomy;
- RADIO CONTINUUM: STARS;
- STARS: PECULIAR;
- STARS: MAGNETIC FIELDS