Pubs.GISS: Abstract of Tucker et al. 1974

NASA - Goddard Institute for Space Studies

+ NASA Portal
+ Goddard Space Flight Center
+ GSFC Earth Sciences Division

Tucker et al. 1974

Tucker, K.D., M.L. Kutner, and P. Thaddeus, 1974: The ethynyl radical C₂H — A new interstellar molecule. Astrophys. J., 193, L115-L119.

Four new interstellar lines have been detected in a number of galactic sources with derived rest frequencies of 87,317.05, 87,328.70, 87,402.10, and 87,407.23 MHz. Based on laboratory ESR data in the solid state, these lines have been positively identified as hyperfine components of the N = 1 → 0 transition of the ethynyl radical C₂H. The astronomical observations yield precise values for the C₂H rotation, spin-doubling, and hyperiine constants, namely, 2B₀-4D₀ = 87,348.74±0.19 MHz, γ = -62.57±0.13 MHz, b = 40.24±0.43 MHz, and c = 12.23±0.35 MHz. Ethynyl is apparently one of the most abundant interstellar polyatomic molecules with column densities in the best sources ~10¹⁵ cm^-2. In the Orion Nebula the north-south extent of C₂H emission is nearly a quarter of a degree.