S. J. George1,2 and I. R. Stevens1
Abstract.
We present radio observations of the {magnetic} chemically peculiar Bp star HR Lup (HD 133880)
at 647 and 277 MHz with the GMRT. At both frequencies the source is not detected but we
are able to determine upper limits to the emission. The 647 MHz limits are particularly
useful, with a 5σ value of 0.45 mJy. Also, no large enhancements of the
emission were seen. The non-detections, along with previously published higher frequency detections,
provide evidence that an optically thick gyrosynchrotron model is the correct mechanism for
the radio emission of HR Lup.
Keywords: magnetic fields -- radio continuum: stars -- stars: chemically peculiar
1Astrophysics Group, The Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge,
Cambridge, CB3 0HE, UK
2Astrophysics and Space Research Group, School of Physics and Astronomy, University of Birmingham,
Birmingham, B15 2TT, UK