GMRT search for 150 MHz radio emission from the transiting extrasolar planets HD 189733 b and HD 209458 b^⋆

¹ CNRS, UMR 7095, Institut d’Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
e-mail: lecaveli@iap.fr
² UPMC Univ. Paris 6, UMR 7095, Institut d’Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
³ National Centre for Radio Astrophysics, TIFR, Post Bag 3, Pune University Campus, 411007 Pune, India
⁴ LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France

Received: 24 May 2011
Accepted: 8 July 2011

Abstract

We report a sensitive search for meter-wavelength emission at 150 MHz from two prominent transiting extrasolar planets, HD 189733 b and HD 209458 b. To distinguish any planetary emission from possible stellar or background contributions, we monitored these systems just prior to, during, and after the planet’s eclipse behind the host star. No emission was detected from HD 209458 b with a 3σ upper limit of 3.6 mJy. For HD 189733 b we obtain a 3σ upper limit of 2.1 mJy and a marginal 2.7σ detection of  ~1900 ± 700   μJy from a direction just 13″ from the star’s coordinates (i.e., within the beam), but its association with the planet remains unconfirmed. Thus, the present GMRT observations provide unprecedentedly tight upper limits for meter wavelength emissions from these nearest two transiting-type exoplanets. We point out possible explanations of the non-detections and briefly discuss the resulting constraints on these systems.