In search of radio emission from exoplanets: GMRT observations of the binary system HD~41004

TL;DR

This study used GMRT to search for radio emissions from the HD 41004 exoplanetary system at low frequencies, setting upper limits on emission strength and discussing potential reasons for non-detection.

Contribution

First deep low-frequency radio observations of the HD 41004 system, providing constraints on exoplanetary radio emission models and detection limits.

Findings

No radio emission detected at 150 MHz and 400 MHz.

Set 3σ upper limits of 1.8 mJy at 150 MHz and 0.12 mJy at 400 MHz.

Discussed possible reasons for non-detection.

Abstract

This paper reports Giant Metrewave Radio Telescope (GMRT) observations of the binary system HD 41004 that are among the deepest images ever obtained at 150~MHz and 400 MHz in the search for radio emission from exoplanets. The HD 41004 binary system consists of a K1 V primary star and an M2 V secondary; both stars are host to a massive planet or brown dwarf. Analogous to planets in our solar system that emit at radio wavelengths due to their strong magnetic fields, one or both of the planet or brown dwarf in the HD 41004 binary system are also thought to be sources of radio emission. Various models predict HD~41004Bb to have one of the largest expected flux densities at 150 MHz. The observations at 150 MHz cover almost the entire orbital period of HD 41004Bb, and about $20\%$ of the orbit is covered at 400 MHz. We do not detect radio emission, setting 3$\sigma$ limits of 1.8 mJy at 150 MHz and 0.12 mJy at 400 MHz. We also discuss some of the possible reasons why no radio emission was detected from the HD 41004 binary system.