October 2017

Octatetraynyl anion

The largest anion identified to date in space is C8H, which goes by the formal (and tongue twisting) name octatetraynyl anion. The detection was reported in 2007 by three groups, initially in back-to-back ApJL papers by Brünken et al. and Remijan et al., followed within a few months by confirming observations reported by Kawaguchi et al. The detection of Brünken et al. was toward TMC-1 while that of Remijan et al. was toward IRC+10216; both groups used data collected with the 100m Robert C. Bird Green Bank Telescope. The detection of Kawaguchi et al. was also toward IRC +10216 based on observations with the 45m telescope at Nobeyama Radio Observatory. A total of 13 different transitions were observed by the three efforts. The detection was made possible by laboratory measurement of the rotational spectrum of C8H by Gupta et al.

Researcher Links
S Brünken
H Gupta
CA Gottlieb
MC McCarthy
P Thaddeus
AJ Remijan
JM Hollis
FJ Lovas
MA Cordiner
TJ Millar
AJ Markwick-Kemper
PR Jewell

To date five anions have been detected in space in the gas phase. In addition to C8H, the detections of the hexatriynyl (C6H) and butadiynyl (C4H) anions were both reported in 2007, while the detections of the cyanoethynyl (C3N) and cyanobutadiynyl (C5N) anions were reported in 2008, and the detection of the cyano (CN) anion was reported in 2010.

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