Non-Detections(nd)—most recent: HCOCH2CH2CN

Isotopologues(iso)—most recent: c-H2C3O

Molecules can exist in a wide range of astrophysical environments, from the extremely cold regions between stars to the atmospheres of stars themselves. Molecules can be present in every stage of the life cycle of stars, from the diffuse and dense clouds that condense into protostellar and protoplanetary systems to mature systems like the Solar System.

Some detections reported on these pages may be controversial, but all are taken from the peer-reviewed astronomical literature. A questionable identification may be removed at a later date if circumstances warrant.

Jacque Crovisier has amassed a comprehensive compilation of species observed to date in the interstellar medium, in comets, or in non-terrestrial planetary atmospheres, plus additional ones which may prove to be found.

See the ApJS article by Brett McGuire, 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules. In addition to lists of observed molecules, the article provides a good overview about astronomical observation and the spectroscopy associated with detecting molecules.