A uGMRT search for radio emission from planets around evolved stars

In this work, we present the results from a study using the Giant Meterwave Radio Telescope (GMRT) to search for radio emission from planets around three evolved stars namely alpha Tau, beta UMi, and beta Gem. Both alpha Tau and beta UMi host massive similar to 6 MJ mass planets at about similar to 1.4 au from the central star, while beta Gem is host to a 2.9 MJ mass planet at 1.7 au from the host star. We observe alpha Tau and beta UMi at two upgraded GMRT bands: band 3 (250-500 MHz) and band 4 (550-900 MHz). We also analysed the archival observations from beta Gem at 150 MHz from GMRT. We did not detect any radio signals from these systems. At 400 MHz, the 3 sigma upper limit is 87 mu Jy beam(-1) for alpha Tau b and 77.4 mu Jy beam(-1) for beta UMi b. From our observations at 650 MHz, we place a 3 sigma upper limit of 28.2 mu Jy beam(-1) for alpha Tau b and 33.6 mu Jy beam(-1) for beta UMi b. For beta Gem b, at 150 MHz, we place an upper limit of 2.5 mJy. At 400 and 650 MHz, our observations are the deepest radio images for any exoplanetary system.