Unveiling the Hot Molecular Core in the Ultracompact H II Region with Extended Emission G12.21-0.10

We present a multiwavelength study of the cometary H II region G12.210.10 using the VLA and OVRO. Both radio continuum (0.3, 0.7, 2 and 3.6 cm) and spectral lines of H41 alpha, (CS)-C-13(2-1) & (1-0), and NH3(2,2) & (4,4) observations are included. We find two 3 mm continuum peaks toward G12.2-0.10; one of them is spatially coincident with the UC H II region, while the other coincides spatially with a molecular clump. We also find that the 0.7, 2 and 3.6 cm continuum and H41 alpha line are only detected toward the UC H II region, while the (CS)-C-13, and NH3 are spatially associated with the molecular clump. Based on the morphology, kinetic temperature (approximate to 86 K), volumetric density (approximate to 1.5x10(6) cm(-3) ) and linear size (approximate to 0.22 pc) of the molecular clump, we suggest this source is consistent with a hot molecular core.