Six transitions of butadiynylidenesilylidyne with J" between
11 and 27 were detected in the circumstellar envelope of CW Leo
(IRC +10216) with the 45 m radiotelescope of the Nobeyama
Radio Observatory between 36 and 86 GHz:
M. Ohishi, N. Kaifu, K. Kawaguchi, A. Murakami, S. Saito, S. Yamamoto, S.-I. Ishikawa, Y. Fujita, Y. Shiratori, and W. M. Irvine,
Detection of a new Circumstellar Carbon Chain Molecule, C4Si
Astrophys. J. 345, L83L86 (1989).