First astronomical detection of the CF+ ion

We report the first astronomical detection of the CF+ (fluoromethylidynium) ion obtained by recent observations of its J = 1 - 0 (102.6 GHz), J = 2 - 1 (205.2 GHz), and J = 3 - 2 (307.7 GHz) pure rotational emissions toward the Orion Bar. Our search for CF+, carried out using the IRAM 30m and APEX 12m telescopes, was motivated by recent theoretical models that predict CF+ abundances of a few x E-10 in UV-irradiated molecular regions where C+ is present. The measurements confirm the predictions. They provide support for our current theories of interstellar fluorine chemistry, which suggest that hydrogen fluoride should be ubiquitous in interstellar gas clouds.