A subarcsecond radio binary associated with AFGL 4029-IRS1

We present sensitive, high angular resolution (0."3) Very Large Array obser vations made at 3.6-cm of the bright infrared source AFGL 4029. We find tha t the radio source G138.295+1.555, associated with AFGL 4029-IRS1, is actua lly a subarcsecond binary separated by 0."6 approximately in the north-sout h direction. There is also fainter emission extending in the east-west dire ction and emanating from G138.295+1.555(S), the southern component of the b inary. We then identify G138.295+1.555(S) as the exciting source of the opt ical and molecular outflow observed in this region. G138.295+1.555(S) appea rs to be one of the few massive young stars associated with a collimated ou tflow. The northern component of the binary, G138.295+1.555(N), appears to exhibit time-variable radio emission and is proposed to be associated with a T Tauri star. The source G138.300+1.558, associated with AFGL 4029-IRS2, is an ultracompact H II region of cometary morphology, possibly ionized by a B1 ZAMS star.