Molecules in Space

Press release (2009) on the detection of ethyl formate and n-propyl cyanide toward the massive star-forming region Sagittarius B2(N).
Pressemitteilung (2009) zur Entdeckung von Ethylformiat und n-Propylcyanid in Richtung des massiven Sternentstehungsgebiets Sagittarius B2(N).

Press release (2008) on the detection of aminoacetontrile toward the massive star-forming region Sagittarius B2(N).

ISM/CSS
extragalactic molecules

Note: Deuterium isotopic species are given separately only if their method of detection is intrinsically different from that of pure hydrogen ones.

The documentations generally provide information on the detection of the respective molecules, including minor isotopic species, molecules in excited vibrational states, or different media in which the species has been detected as well as links to articles.

All molecules have been detected (also) by rotational spectroscopy in the radiofrequency to far-infrared regions unless indicated otherwise.
* indicates molecules that have been detected by their rotation-vibration spectrum,
** those detected by electronic spectroscopy only.

Transition metal molecules detected in atmospheres of stars by electronic spectroscopy are currently not included.

Note: Questionable or rebuted detections have been omitted from the table. Some noteworthy cases are given below the table. Tentative detections, which have a reasonable chance to be correct, are indicated by "?". Usually the number of observed transitions that are, at least, fairly free of overlap is small. Some detections that have been reported as secure ones are indicated by "(?)" because (partial) overlap of lines cannot be ruled at the moment or because the line list is somewhat small; obviously, there may be cases on the edge.

As the decision whether a molecule can be considered as detected frequently is a controversial one we refrain from stating an exact number of molecules as detected. As of February 2009, there are approximately 150 molecules listed as detected in the interstellar medium or circumstellar shells. Most likely there are some for which the detection should be viewed as tentative or questionable. In the course of providing background information, adjustments will be made. Two reported detections have been questioned seriously. Therefore, these are viewed currently as "probably not yet detected" – see below. Thus, we recommend phrases such as "about 150 molecules have been detected in the interstellar medium or circumstellar shells".

The number of molecules detected in extragalactic sources is 36 plus 2 tentative detections.

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