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 $α$~Tau, $β$~UMi, and $β$~Gem. Both $α$~Tau and $β$~UMi host massive $\sim$ 6 $M_J$ mass planets at about $\sim$1.4 au from the central star, while $β$~Gem is host to a 2.9 $M_J$ mass planet at 1.7 au from the host star. We observe $α$~Tau and $β$~ UMi at two u(upgraded)GMRT bands; band~3 (250-500~MHz) and band~4 (550-900~MHz). We also analyzed the archival observations from $β$ Gem at 150~MHz from GMRT. We did not detect any radio signals from these systems. At 400~MHz, the 3$σ$ upper limit is 87 $μ$Jy/beam for $α$~Tau~{b} and 77.4 $μ$Jy/beam for $β$~UMi~{b}. From our observations at 650~MHz, we place a 3$σ$ upper limit of 28.2 $μ$Jy/beam for $α$~Tau~b and 33.6 $μ$Jy/beam for $β$~UMi~b. For $β$ Gem b, at 150~MHz, we place an upper limit of 2.5 mJy. At 400~MHz and 650~MHz, our observations are the deepest radio images for any exoplanetary system.