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We report a sensitive search for meter-wavelength emission at 244 and 614 MHzfrom HD189733b, the nearest known extrasolar transiting planet of `hot-Jupiter'type. To discriminate any planetary emission from possible stellar orbackground contributions, we observed the system for 7.7 hours encompassing theplanet's eclipse behind the host star. These GMRT observations provide very low(3 sigma) upper limits of 2 mJy at 244 MHz and 160 micro-Jy at 614 MHz. Theselimits are, respectively, about 40 and 500 times deeper than those reportedrecently at a nearby frequency of 340 MHz. Possible explanations of ournon-detection include: (1) the Earth being outside the planet's emission beam;(2) its highly variable emission with more rapid flaring than the temporalsampling in our observations; (3) the planetary emission being intrinsicallytoo weak; or more likely, (4) the emission being predominantly at lowerfrequencies because of a weak planetary magnetic field. We briefly discussthese possibilities and the constraints on this exo-planetary systemenvironment.

GMRT radio observations of the transiting extrasolar planet HD189733b at 244 and 614 MHz