Suggestions for an interstellar cyclopropene search

Abstract

Following tentative detection of cyclopropene (C3H4) in Sgr B2 through its transition 322−221, several attempts to con rm the presence of cyclopropene in astronomical objects (including Sgr B2 itself) have been made. We suggest that cyclopropene may be observed in astronomical objects through its transition 220−221 at 3.67218 GHz, in absorption, even against the cosmic 2.7 K background, in a region having low density and low kinetic temperature.