The enigmatic radio emission from θ 1 Orionis A

The bright star θ1 Orionis A, the third most luminous OB star in the Orion Trapezium Cluster, is known as a strongly variable non-thermal radio source. The physical nature of the emission mechanism has been a matter of debate since almost two decades. In this contribution we re-analyse available radio data in combination with near-infrared observations to investigate the radio-emission mechanism and the nature of the underlying stellar source. The constraints on the size of the non-thermal radio emission imply the presence of very large magnetic structures, while the infrared data suggest the stellar source is a pre-main sequence intermediate mass star. We therefore suggest that the flaring radio emission of θ1 Orionis A emerges from strong magnetic shearing and reconnection between the magnetic (possibly chemically peculiar) intermediate-mass star θ1 Orionis A2 and its