The polarization mode of the auroral radio emission from the early-type star HD142301

TL;DR

This paper reports the detection and analysis of highly polarized auroral radio emission from the early-type magnetic star HD142301, revealing polarization reversals linked to stellar magnetic field orientation.

Contribution

It provides the first detailed characterization of auroral radio emission from HD142301, linking polarization behavior to magnetic field geometry and emission mechanisms.

Findings

Detection of highly polarized auroral radio emission from HD142301

Polarization reversal correlates with stellar magnetic field orientation

Emission amplifies one magneto-ionic mode, explaining circular polarization

Abstract

We report the detection of the auroral radio emission from the early-type magnetic star HD142301. New VLA observations of HD142301 detected highly polarized amplified emission occurring at fixed stellar orientations. The coherent emission mechanism responsible for the stellar auroral radio emission amplifies the radiation within a narrow beam, making the star where this phenomenon occurs similar to a radio lighthouse. The elementary emission process responsible for the auroral radiation mainly amplifies one of the two magneto-ionic modes of the electromagnetic wave. This explains why the auroral pulses are highly circularly polarized. The auroral radio emission of HD142301 is characterized by a reversal of the sense of polarization as the star rotates. The effective magnetic field curve of HD142301 is also available making it possible to correlate the transition from the left to the right-hand circular polarization sense (and vice-versa) of the auroral pulses with the known orientation of the stellar magnetic field. The results presented in this letter have implications for the estimation of the dominant magneto-ionic mode amplified within the HD142301 magnetosphere.