Detection of a new interstellar molecule, H2CN

Abstract

We have detected a new interstellar molecule, H2CN (methylene amidogen), in the cold, dark molecular cloud TMC-1. The column density of H2CN is estimated to be ∼ 1.5 × 1011 cm-2 by assuming an excitation temperature of 5 K. This column density corresponds to a fractional abundance relative to H2 of ∼1.5 × 10-11. This value is more than three orders of magnitude less than the abundance of the related molecule HCN in TMC-1. We also report a tentative detection of H2CN in Sgr B2(N). The formation mechanism of H2CN is discussed. Our detection of the H2CN molecule may suggest the existence of a new series of carbon-chain molecules, CH2CnN (n = 0, 1, 2, ...).