Ethanimine, CH₃CHNH, is the the next heavier homolog of methanimine, H₂CNH. It has been identified in spectra taken with the GBT 100 m telescope toward Sgr B2(N) by
R. A. Loomis, D. P. Zaleski, A. L. Steber, J. L. Neill, M. T. Muckle, B. J. Harris, J. M. Hollis, P. R. Jewell, V. Lattanzi, F. J. Lovas, O. Martinez, Jr., M. C. McCarthy, A. J. Remijan, B. H. Pate, and J. F. Corby,
The Detection of Interstellar Ethanimine (CH₃CHNH) from Observations Taken during the GBT PRIMOS Survey
Astrophys. J 765, Art. No. 9 (2013).
6 rotational transitions were detected for the lower energy E-conformer and 4 for the higher energy Z-conformer. The transitions had J < 4 and K_a < 1, occured between 13 and 48 GHz and were mostly seen in absorption. Two higher energy rotational transitions of the E-conformer were seen in emission. All transitions displayed well resolved CH₃ internal rotation splitting and some showed ¹⁴N hyperfine splitting. The lines were detected in the two well known velocity components 64 km/s and 82 km/s, though (partial) overlap occured for the latter in some lines. A rotational temperature of 6 K was assumed.
These, as well as other observations of fairly complex molecules toward Sgr B2(N) at apperently low rotational temperatures, may be related to findings by
M. A. Requena-Torres, J. Martín-Pintado, A. Rodríguez-Franco, S. Martín, N. J. Rodríguez-Fernández, and P. de Vicente,
Organic Molecules in the Galactic Center – Hot Core Chemistry without Hot Cores
Astron. Astrophys. 455, 971–985 (2006);
and by
M. A. Requena-Torres, J. Martín-Pintado, S. Martín, and M. R. Morris,
The Galactic Center: The Largest Oxygen-bearing Organic Molecule Repository
Astrophys. J. 672, 352–360 (2008).

Contributor(s): H. S. P. Müller; 02, 2013