Investigating the origins of a single magnetic star within a binary system
Date:
HD148937 is one of the three Galactic O-type sources belonging to the rare class of Of?p objects. These stars are characterised by recurrent spectral variations, the origin of which is found to be their strong magnetic fields. Originally thought to be a single star, long baseline near-IR interferometry with PIONIER has revealed HD148937 to be a binary system. In this presentation I will discuss our investigations into the source using a combination of multi-epoch GRAVITY and PIONIER data. These data reveal that the two components are of similar brightness but one star shows the BrG line in emission and the other in absorption, confirming that only one of the two stars is magnetic. Combining our data with existing spectroscopic measurements, a preliminary 3D orbit of the system can be obtained and subsequently absolute masses. We use these new constraints to discuss the evolutionary status of this unique object in the context of the origin of the magnetic star.