2009A&A...500L..51L

We report a sensitive search for meter-wavelength emission at 244 and 614MHz from HD 189733b, the nearest known extrasolar transiting planet of ``hot-Jupiter'' type. To discriminate any planetary emission from possible stellar or background contributions, we observed the system for 7.7h encompassing the planet's eclipse behind the host star. These GMRT observations provide very low (3σ) upper limits of 2mJy at 244MHz and 160µJy at 614MHz. These limits are, respectively, about 40 and 500 times deeper than those reported recently at a nearby frequency of 340MHz. Possible explanations of our non-detection include: (1) the Earth being outside the planet's emission beam; (2) its highly variable emission with more rapid flaring than the temporal sampling in our observations; (3) the planetary emission being intrinsically too weak; or more likely; (4) the emission being predominantly at lower frequencies because of a weak planetary magnetic field. We briefly discuss these possibilities and the constraints on this exo-planetary system environment.