On the progress in Odin’s hunt for molecules Original Research Article

Glimpses of new results from Odin’s fourth to sixth years of operation are presented: the first detection of interstellar O2; the high water abundance in the M 42/Orion KL interface region; new results from the Orion KL spectral scan, including considerably improved knowledge of source physics and chemistry; the constant H2O/HCO+ abundance ratio observed in diffuse, spiral arm clouds; mapping of shock-enhanced water emission in some nearby bipolar outflows; meaningful upper limits to the water abundance in nearby starburst galaxies; new mapping of the water emissions and absorptions in the Galactic Centre region – Sgr A; abundant self-absorbing water observed in the circumstellar envelope of R Doradus; very successful observations of many comets – including Tempel 1 (the target of Deep Impact) and recent observations of an outburst in the disintegrating Comet 73P/Schwassmann–Wachmann 3; and finally a note on our Odin searches for primordial molecules – potential structure probes during the dark ages of the evolution of the Universe.