Limits on low frequency radio emission from southern exoplanets with the Murchison Widefield Array

TL;DR

This study used the Murchison Widefield Array to search for low frequency radio emissions from 17 exoplanetary systems, setting upper limits on emission strength but detecting none, advancing the systematic search for exoplanet radio signals.

Contribution

First systematic low frequency radio survey of exoplanets with the MWA, providing new upper limits and expanding the observational dataset.

Findings

No radio emission detected at 154 MHz.

Established upper limits on circularly polarised emission.

Results are comparable to the best existing low frequency limits.

Abstract

We present the results of a survey for low frequency radio emission from 17 known exoplanetary systems with the Murchison Widefield Array. This sample includes 13 systems that have not previously been targeted with radio observations. We detected no radio emission at 154 MHz, and put 3 sigma upper limits in the range 15.2-112.5 mJy on this emission. We also searched for circularly polarised emission and made no detections, obtaining 3 sigma upper limits in the range 3.4-49.9 mJy. These are comparable with the best low frequency radio limits in the existing literature and translate to luminosity limits of between 1.2 x 10^14 W and 1.4 x 10^17 W if the emission is assumed to be 100% circularly polarised. These are the first results from a larger program to systematically search for exoplanetary emission with the MWA.