HD 93129A at different radio scales

P. BENAGLIA; S. M. DOUGHERTY; C. PHILLIPS; B. KORIBALSKI; T. TZIOUMIS

Viña del Mar, Chile

Workshop; The Interferometric View on Hot Stars; 2009

ESO/U. de Valparaíso

Recent observations toward the O2 If* star HD 93129A have revealed important non-thermal radio emission, and that it has an early O companion 140 AU away if at 2.5 kpc (FGS-HST data). These facts strongly support the possibility of a massive stars wind-collision region as the acceleration site of the synchrotron-emitting relativistic electrons. We have carried out LBA VLBI observations at 2.37 GHz to resolve the non-thermal source, and search for a bow-shock shape, typical of a wind-collision region. Preliminary results are presented here.