M. C. McCarthy et al 2006 ApJ 652 L141 doi:10.1086/510238
M. C. McCarthy1, C. A. Gottlieb1, H. Gupta1,2 and P. Thaddeus1
Show affiliationsThe negative molecular ion C6H- has been detected in the radio band in the laboratory and has been identified in the molecular envelope of IRC +10216 and in the dense molecular cloud TMC-1. The spectroscopic constants derived from laboratory measurements of 17 rotational lines between 8 and 187 GHz are identical to those derived from the astronomical data, establishing unambiguously that C6H- is the carrier of the series of lines with rotational constant 1377 MHz first observed by K. Kawaguchi et al. in IRC +10216. The column density of C6H- toward both sources is 1%-5% that of neutral C6H. These surprisingly high abundances for a negative ion imply that if other molecular anions are similarly abundant with respect to their neutral counterparts, they may be detectable both in the laboratory at high resolution and in interstellar molecular clouds.
ISM: molecules; line: identification; molecular data; molecular processes; radio lines: ISM
Issue 2 (2006 December 1)
Received 2006 September 28, accepted for publication 2006 October 17
Published 2006 November 20
M. C. McCarthy et al 2006 ApJ 652 L141
Scott A. Hughes and Kristen Menou 2005 ApJ 623 689
A. Dieball et al. 2007 ApJ 670 379
Nami Sakai et al 2007 ApJ 667 L65
Steven D. Deines and Carol A. Williams 2007 The Astronomical Journal 134 64
A. Fuente and J. Martín-Pintado 1997 ApJ 477 L107
José Cernicharo et al 2000 ApJ 534 L199
Fabian Walter et al 2004 ApJ 615 L17
Phyllis M. Lugger et al. 2007 ApJ 657 286
R. L. Allen et al 2006 ApJ 640 L83