  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.
