Radio detection of interstellar sulfur dioxide

Abstract

Interstellar sulfur dioxide (S02) has been detected in emission from the direction of the Orion Nebula molecular cloud and from Sgr B2. SO, is the heaviest interstellar molecule detected to date, and the only nonlinear triatomic molecule 、.vhich does not contain hydrogen ‘ The remarkable Orion emission profiles suggest that two components are supporting the SO, emission: a dense circumstellar-type envelope, which may be in maser emission, and a warm galactic cloud component.