CARMA CO(J=2-1) OBSERVATIONS OF THE CIRCUMSTELLAR ENVELOPE OF BETELGEUSE

We report radio interferometric observations of the (CO)-C-12-O-16 1.3 mm J = 2 - 1 emission line in the circumstellar envelope of the Msupergiant alpha Ori and have detected and separated both the S1 and S2 flow components for the first time. Observations were made with the Combined Array for Research in Millimeter- wave Astronomy (CARMA) interferometer in the C, D, and E antenna configurations. We obtain good u-v coverage (5-280 k lambda) by combining data from all three configurations allowing us to trace spatial scales as small as 0.'' 9 over a 32 '' field of view. The high spectral and spatial resolution C configuration line profile shows that the inner S1 flow has slightly asymmetric outflow velocities ranging from -9.0 km s(-1) to +10.6 km s(-1) with respect to the stellar rest frame. We find little evidence for the outer S2 flow in this configuration because the majority of this emission has been spatially filtered (resolved out) by the array. We also report a SOFIA-GREAT CO(J = 12 - 11) emission line profile, which we associate with this inner higher excitation S1 flow. The outer S2 flow appears in the D and E configuration maps and its outflow velocity is found to be in good agreement with high-resolution optical spectroscopy of Ki obtained at the McDonald Observatory. We image both S1 and S2 in the multi-configuration maps and see a gradual change in the angular size of the emission in the high absolute velocity maps. We assign an outer radius of 4 '' to S1 and propose that S2 extends beyond CARMA's field of view (32 '' at 1.3 mm) out to a radius of 17 '', which is larger than recent single-dish observations have indicated. When azimuthally averaged, the intensity falloff for both flows is found to be proportional to R-1, where R is the projected radius, indicating optically thin winds with rho alpha R-2.