Revealing the Molecular Universe: One Antenna is Never Enough - IN HONOR OF THE ACADEMIC RETIREMENT OF JACK WELCH,Book Series: ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES,Volume: 356 Pages: 270-274,Published: 2006
We used the BIMA array to observe the hot molecular core W3(E2O). Our continuum maps at wavelengths of 1.4mm and 2.8mm both achieve sub-aresecond angular resolutions and show a double-peaked morphology. The angular separation of the two sources is 1."19 corresponding to 2.43 x 10(3) AU at the source distance of 2.04 kpc. The flux densities of the two sources at lambda lambda 1.4nnn and 2.8mm have a spectral index of 3, translating to an opacity law of kappa(v) alpha v. The small spectral indices suggest that grain growth has begun in the hot core. We have also observed 5 of the K-components of the methyl cyanide (CH3CN) J = 12-11 transition. A radial velocity difference of 2.81 km s(-1) is found for the gas in the two continuum peaks. Interpreting these two sources as binary components in orbit about one another, we find a minimum mass of 22 M-circle dot for the system. Power-law density distributions close to the free-fall value, r(-1.5), are found for both components, suggesting continuing accretion. The derived luminosities suggest the two sources have equivalent zero-age main sequence (ZAMS) spectral type 130.5 - B0. A velocity gradient previously detected. may be explained by unresolved binary rotation with a small velocity difference.