Knowledge Bank

Because of the lack of a permanent dipole moment, detection of pure carbon clusters in the interstellar medium by conventional microwave astronomy is unlikely. The best vehicle for the detection of these molecules in cold interstellar dust forming regions is the low frequency bending vibrations in the far-infrared region of the spectrum. Our group has the ability to measure the far-infrared bending frequencies of these molecules directly in the $laboratory.1$ Using these laboratory data, it is then possible to conduct interstellar searches for these molecules using far-infrared heterodyne astronomy aboard the Kuiper Airborne Observatory. Using this method, we have recently detected the R(2) transition of the $\nu 2$ fundamental of $C3$ in Sagittarius $B22.$ This work represents the first detection of a pure carbon cluster in the cold interstellar medium. It is hoped that we can extend this work to larger carbon clusters and determine the role of pure carbon in interstellar dust formation.