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Outstanding Stellar Microwave Flares in 1986

Published online by Cambridge University Press:  25 April 2016

O. B. Slee
Affiliation:
Division of Radiophysics, CSIRO, Sydney
G. J. Nelson
Affiliation:
Division of Radiophysics, CSIRO, Sydney
R. T. Stewart
Affiliation:
Division of Radiophysics, CSIRO, Sydney
Alan E. Wright
Affiliation:
Division of Radiophysics, CSIRO, Sydney
David L. Jauncey
Affiliation:
Division of Radiophysics, CSIRO, Sydney
A. E. Vaughan
Affiliation:
Department of Mathematics and Physics, Macquarie University, Sydney
M. I. Large
Affiliation:
School of Physics, University of Sydney
J. D. Bunton
Affiliation:
School of Electrical Engineering, University of Sydney
W. L. Peters
Affiliation:
Mount Stromlo and Siding Spring Observatories, Canberra
S. G. Ryan
Affiliation:
Mount Stromlo and Siding Spring Observatories, Canberra

Abstract

We describe bright microwave events that were first detected with the Parkes 64-m telescope at 8.4 or 22 GHz from six active-chromosphere stars. In some flares spectral data were obtained over a large frequency range from simultaneous measurements with the Parkes reflector (8.4 or 22 GHz), the Tidbinbilla interferometer (8.4 and 2.29 GHz), the Fleurs synthesis telescope (1.42 GHz) and the Molonglo Observatory synthesis telescope (0.843 GHz). Data on circular polarization were obtained from the Parkes observations at 8.4 GHz.

The stars were in a wide variety of evolutionary states, ranging from a single pre-main-sequence star (HD 36705), two RS CVn binaries (HD 127535, HD 128171), an Algol (HD 132742) and two apparently single K giants (HD 32918 and HD 196818). Their high brightness temperatures, positive spectral indices and low polarization are consistent with optically thick gyrosynchrotron emission from mildly relativistic electrons with average energies 0.5 to 3 MeV gyrating in inhomogeneous magnetic fields of 5 to 100 G.

Type
Stellar
Copyright
Copyright © Astronomical Society of Australia 1987

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References

Slee, O. B., Haynes, R. F. and Wright, A. E., 1984, Mon. Not. R. Astron. Soc., 208, 865.CrossRefGoogle Scholar
Slee, O. B. and 10 others, 1987a, Mon. Not. R. Astron. Soc., (in press).Google Scholar
Slee, O. B. and 6 others, 1987b, submitted to Mon. Not. R. Astron. Soc. Google Scholar
Stewart, R. T. and Nelson, G. J., 1979, Proc. Astron. Soc. Aust., 3, 390.Google Scholar
Vaughan, A. E. and Large, M. I., 1987, Proc. Astron. Soc. Aust., 7 Google Scholar