Monitoring the radio emission of Proxima Centauri

Abstract

We present results from the most comprehensive radio monitoring campaign towards the closest star to our Sun, Proxima Centauri. We report 1.1 to 3.1 GHz observations with the Australian Telescope Compact Array over 18 consecutive days in April 2017. We detect radio emission from Proxima Centauri for most of the observing sessions, which spanned $\sim$1.6 orbital periods of the planet Proxima b. The radio emission is stronger at the low-frequency band, centered around 1.6 GHz, and is consistent with the expected electron-cyclotron frequency for the known star's magnetic field intensity of about 600 Gauss. The 1.6 GHz light curve shows an emission pattern that is consistent with the orbital period of the planet Proxima b around the star Proxima, with its maxima of emission happening near the quadratures. We also observed two short-duration (a few minutes) flares and a long-duration (about three days) burst whose peaks happened close to the quadratures. We find that the frequency, large degree of circular polarization, change of the sign of circular polarization, and intensity of the observed radio emission are all consistent with expectations from electron cyclotron-maser emission arising from sub-Alfvénic star-planet interaction. We interpret our radio observations as signatures of interaction between the planet Proxima b and its host star Proxima. We advocate for monitoring other dwarf stars with planets to eventually reveal periodic radio emission due to star-planet interaction, thus opening a new avenue for exoplanet hunting and the study of a new field of exoplanet-star plasma interaction.

14 pages, 11 figures. Accepted on December 2, 2020 in A&A (main journal), several typos corrected

References in corpus (10)

• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Periodic Bursts of Coherent Radio Emission from an Ultracool Dwarf
• The Arecibo Detection of the Coolest Radio-flaring Brown Dwarf
• ASKAP Detection of Periodic and Elliptically Polarized Radio Pulses from UV Ceti
• ALMA Discovery of Dust Belts Around Proxima Centauri
• Probabilistic Constraints on the Mass and Composition of Proxima b
• Discovery of electron cyclotron MASER emission from the magnetic Bp star HD 133880 with the Giant Metrewave Radio Telescope
• Detection of coherent emission from the Bp star HD 142990 at uGMRT frequencies
• Search for exoplanets and brown dwarfs with VLBI
• Kinetic Simulation of the Electron-Cyclotron Maser Instability: Relaxation of Electron Horseshoe Distributions

Cited by in corpus (36)

• Planet-induced radio emission from the coronae of M dwarfs: the case of Prox Cen and AU Mic
• Coherent radio bursts from known M-dwarf planet host YZ Ceti
• A scaling relationship for non-thermal radio emission from ordered magnetospheres: from the top of the Main Sequence to planets
• V-LoTSS: The Circularly-Polarised LOFAR Two-metre Sky Survey
• The CARMENES search for exoplanets around M dwarfs: Stable radial-velocity variations at the rotation period of AD~Leonis -- A test case study of current limitations to treating stellar activity
• The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc
• The CARMENES search for exoplanets around M dwarfs, Wolf 1069 b: Earth-mass planet in the habitable zone of a nearby, very low-mass star
• The CARMENES search for exoplanets around M dwarfs. A long-period planet around GJ 1151 measured with CARMENES and HARPS-N data
• The CARMENES search for exoplanets around M dwarfs. Two terrestrial planets orbiting G 264-012 and one terrestrial planet orbiting Gl 393
• Hunting for exoplanets via magnetic star-planet interactions: geometrical considerations for radio emission
• Radio-Loud Exoplanet-Exomoon Survey (RLEES): GMRT Search for Electron Cyclotron Maser Emission
• The TESS View of LOFAR Radio-Emitting Stars
• The Habitable-zone Planet Finder Detects a Terrestrial-mass Planet Candidate Closely Orbiting Gliese 1151: The Likely Source of Coherent Low-frequency Radio Emission from an Inactive Star
• Radio masers on WX UMa: hints of a Neptune-sized planet, or magnetospheric reconnection?
• A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone
• MHD study of extreme space weather conditions for exoplanets with Earth-like magnetospheres: On habitability conditions and radio-emission
• GJ 806 (TOI-4481): A bright nearby multi-planetary system with a transiting hot, low-density super-Earth
• Follow-up LOFAR observations of the $\tau$ Boötis exoplanetary system
• Testing a scaling relation between coherent radio emission and physical parameters of hot magnetic stars
• MHD simulations of the space weather in Proxima b: Habitability conditions and radio emission
• TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf
• The Mouse that Squeaked: A small flare from Proxima Cen observed in the millimeter, optical, and soft X-ray with Chandra and ALMA
• A Pilot Radio Search for Magnetic Activity in Directly Imaged Exoplanets
• TOI-4438 b: a transiting mini-Neptune amenable to atmospheric characterization
• Star-Planet Interaction: Wave Structures and Wing-Wing Interaction
• Magnetized winds of M-type stars and star-planet magnetic interactions: uncertainties and modeling strategy
• ROME III. The Arecibo Search for Star-Planet Interactions at 5 GHz
• Searching for star-planet interactions in GJ 486 at radio wavelengths with the uGMRT
• The Proxima Centauri Campaign -- First Constraints On Millimeter Flare Rates from ALMA
• A circularly polarized low-frequency radio burst from the exoplanetary system HD 189733
• Radio Emission from a Nearby M dwarf Binary
• ROME IV. The Arecibo Search for Substellar Magnetospheric Radio Emissions in Purported Exoplanet-Hosting Systems at 5 GHz
• MHD Simulations Preliminarily Predict The Habitability and Radio Emission of TRAPPIST-1e
• Spectroscopic Characterization of LOFAR Radio-emitting M dwarfs
• Upper Limits on Planet-Induced GHz Radio Emission from Inactive M Dwarfs
• First detection of variable radio emission originating from the infant planetary system V1298 Tau