WATER MASERS IN ORION

Measurements of the 6(16) --> 5(23) line of H2O at 1.3 cm in the Orion region of star formation are reported. With a spatial resolution of a pproximate to 0.'' 1, H2O maser emission was detected in two regions: Orion BN/KL and Orion S. The well-known masers in the BN/KL region are distributed in a 30 '' by 30 '' area. The ''shell'' masers, within th e BN/KL region, are distributed in a 2 '' by 0.'' 5 strip centered on radio source I and are offset from IRc2. The average shell maser spect rum is doubly peaked, resembling the spectrum of the upsilon = 1 SiO m asers. The shell masers have deconvolved sizes of 24-38 AU, slightly s maller than the synthesized beam. Newly detected H2O masers in the Ori on S region are distributed in a 15 '' by 20 '' area. One cluster of m asers in the Orion S region is found in a thin 0.''(6 strip. The veloc ity range of the masers in this cluster is nearly 65 km s(-1). We sugg est that this cluster of masers is associated with the energetic sourc e of the Orion S molecular outflow. A search in the Orion S region for associated maser emission in the ground-state OH main lines and the 9 (2) --> 10, A(+) and 6(2) --> 6(1) E lines of CH3OH gave only upper li mits, as did a search for centimeter-wavelength continuum.Near-infrare d images of the Orion region are presented in the J, H, and K bands. T hree objects with very red near-infrared colors were detected in the O rion S region, near the H2O masers and the previously detected millime ter-wavelength dust continuum peak. One of these objects exhibits near -infrared colors consistent with a B2 zero-age main-sequence star. Alt hough this object may heat the northern part of the Orion S dust cloud , its luminosity and separation from the dust maximum make it unlikely that it alone heats the entire Orion S region. More likely, the prima ry heat source of the Orion S region is deeply embedded in dust and co mpletely extincted in the near-infrared.