ON THE DETECTABILITY OF THE GAS OF OTHER SOLAR NEBULAE

Velocity profiles of the (CO)-C-12 (J = 1-0) and (CO)-C-13 (J = 1-0) lines emitted from the solar nebula are numerically calculated by taking account of the radiative transfer of the lines. For the solar nebula we adopt the two theoretical models of a low-mass (approximately 0.01 M .) nebula (i.e., Kyoto model) and a high-mass (approximately 1 M .) nebula (i.e., Cameron model). It is shown that the calculated profiles typically have double peaks at the velocities of +/- 2-5 km s-1, which are separable from ambient emission, and that the profiles vary greatly depending on the inclination angle between the rotation axis of the nebula and the line of sight. The peak flux densities of the profiles are converted into the antenna temperatures of 0.005 to 0.15 K for T Tauri stars in the Taurus complex (140 pc), if we use the 45 m telescope of the Nobeyama Radio Observatory (NRO). It is concluded from our numerical results that the gas of other solar nebulae with the radius of approximately 100 AU can be detected by radio observations of the CO lines until the gas dissipates.