K. Kawaguchi, S. Takano, M. Ohishi, S.-I. Ishikawa, K. Miyazawa, N. Kaifu,
K. Yamashita, S. Yamamoto, S. Saito, Y. Ohshima, and Y. Endo
reported on the
Detection of HNCCC in TMC-1
Astrophys. J. 396, L49 (1992).
The Nobeyama 45 m telescope was used to detect the J = 3 2, 4 3, and 5 4 transitions near 28.0, 37.3, and 46.7 GHz. The HCCNC isomer was found only slightly earlier, whereas the HC3N isomer had been known for a considerable time.
P. D. Gensheimer reported on
Observations of HCCNC and HNCCC in IRC+10216
Astrophys. Space Sci. 251, 199 (1997).
The NRAO 12 m telescope was used to detect the J = 11 10 transition near 102.7 GHz. The HCCNC to HNC3 ratio is about 8, similar to that in TMC-1. Because of only one detected line, this report should be viewed with some caution.
C. Vastel, K. Kawaguchi, D. Quénard, M. Ohishi, B. Lefloch, R. Bachiller,
and H. S. P. Müller
used the IRAM 30 m telescope for
High Spectral Resolution Observations of HNC3 and HCCNC in the L1544 Pre-stellar Core
Mon. Not. R. Astron. Soc. 474, L76 (2018).
The J = 8 7, 9 8, and 10 9 transitions were detected near 74.7, 84.0, and 93.4 GHz. The column density is only slightly smaller than that in TMC-1, similar to HCCNC, even though HC3N is less abundant by about one order of magnitide in L1544 compared to TMC-1.