2000A&A...357L..37Z

We observed the hydroxyl (OH) masers in the ground-state 1665 and 1667 MHz transitions toward the cometary HII region G34.3+0.2 with the Very Long Baseline Array (VLBA). Our observations were sensitive to both right and left circular polarizations with a spectral resolution of 0.176km/s and an angular resolution of 8x31 mas. We detected 120 maser features in a region of 3x6 arcsec, including 15 Zeeman pairs separated by an average distance of only 2 mas were identified. The OH masers are associated with two newly formed stars in the G34.3+0.2 complex. One star ionizes a weak, ultra-compact HII region (source B) and has a magnetic field orientation predominantly away from us. The other star, or stars, power the dominant cometary HII region (source C) and the magnetic field along the northern rim of the cometary source is directed toward us.