Subarcsecond-Resolution 86 GHz Continuum Maps of Orion KL

The BIMA array was used to map the 86 GHz continuum emission from Orion KL with 0 6 angular resolution. The Becklin-Neugebauer object (BN) and radio source I, coincident with the IRc2 SiO maser, were detected as unresolved sources with flux densities of 84 ± 10 and 34 ± 5 mJy, respectively. The radio spectra of both sources are well fit by models of free-free emission from ionized circumstellar envelopes. The offset of BN from the SiO maser is determined with ±0 02 accuracy. Comparison with earlier data suggests that BN and source I are moving apart at ~0 02 yr -1 , 50 km s -1 at the distance of Orion. We suggest that BN is a runaway B star that lies near the Kleinmann-Low Nebula purely by coincidence.