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T.S. Bastian (NRAO,DESPA), G.A. Dulk, Y. Leblanc (DESPA), R. Sault (ATNF)
Fifteen giant planets of mass about 1--13 M\rm J and eleven brown dwarfs of mass 13--50~M\rm J have now been discovered by their gravitational effects on solar-like stars. There is reason to believe that these objects have magnetic fields and that they emit meter- or decimeter-wavelength radio radiation through the electron cyclotron maser mechanism. Although the visible and infrared radiation from exoplanets is much weaker than that of the parent stars, the radio emission need not necessarily be. Extremely intense radio emission can be generated by the electron-cyclotron maser instability. For Jupiter the cyclotron-maser radiation is 105-106 times more intense than its synchrotron emission from the radiation belts and its thermal emission from the disk. If detected from a planet, several important parameters can be deduced, e.g. its rotation period and magnetic field strength.
We report the results of searchs for radio emission from a sample of confirmed extrasolar planets and brown dwarfs. The Very Large Array (VLA) was used in late 1996 to observe seven planets and two brown dwarfs at 1400 and 330 MHz. In early 1998, both 47 UMa (planet) and HD98239 (brown dwarf) were observed at 330 and the new 74 MHz system.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
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The author(s) of this abstract have provided an email address for comments about the abstract: bastian@despa.obspm.fr