Unraveling the identity of B11244 (l-C3H+/C3H-): An observational approach

Abstract

Pety et al. (2012) have reported the detection of eight transitions of a closed-shell, linear mol. (B11244) in observations toward the Horsehead PDR which they attribute to l-C_3H+, a mol. not previously studied in the lab. Such identifications of mols. without lab. spectra are rare. The attribution of these signals to the l-C_3H+ cation has since been disputed by Huang et al. (2013) and Fortenberry et al. (2013), with the latter suggesting the anion, C_3H-, as a more probable carrier based on high-level theor. work. Here, we examine observations of the Horsehead PDR, Sgr B2(N), TMC-1, and IRC+10216 in the context of answering the question: "What if B11244 is actually C_3H-" We present an anal. of the spectroscopy of C_3H-, the probable formation and destruction pathways of the anion in these environments, and the relative abundance of C_3H compared to other known mol. anions.