Molecular oxygen in the ρ Ophiuchi cloud ***

Context.Molecular oxygen, O2, has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission. Aims.The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. Methods.The Odin …