[{"id":159,"title":"Sulfur-Bearing Polycyclic Aromatic Hydrocarbons in Interstellar Environments","sha":"c910680b94a3558d7ca47a4fe2046c4a","user_id":555,"state":"published","body":"Polycyclic aromatic hydrocarbons (PAHs) are widely studied in an astrophysical context. Studies have also been performed on nitrogen-bearing PAH species ([Hudgins+2005](http://adsabs.harvard.edu/abs/2005ApJ...632..316H)) and unsuccessful searches have been performed for interstellar nitrogen-bearing PAHs ([Ali-Haïmoud+2015](http://adsabs.harvard.edu/abs/2015MNRAS.447..315A)). Laboratory irradiation of ices containing aromatic hydrocarbons has recently been found to produce oxygen and nitrogen heterocycles ([Materese+2015](http://adsabs.harvard.edu/abs/2015ApJ...800..116M)), though previous astronomical searches for such heterocycles have proven unsuccessful ([Charnley+2005](http://adsabs.harvard.edu/abs/2005AdSpR..36..137C); [Dezafra+1972](http://adsabs.harvard.edu/abs/1972ApL....10....1D); [Kutner+1980](http://adsabs.harvard.edu/abs/1980ApJ...242..541K)). \r\n\r\nHowever, astrochemical studies on interstellar sulfur are quite neglected. Sulfur heterocycles have received little astrochemical attention, despite having been detected inside meteorites ([Krishnamurthy+1992](http://www.sciencedirect.com/science/article/pii/001670379290015B); [Sephton+2002](http://rsta.royalsocietypublishing.org/content/363/1837/2729)). Thiophenes are expected to be stable at interstellar medium (ISM) temperatures ([Guillemin+2010](http://adsabs.harvard.edu/abs/2010cosp...38.3235G)). Observed sulfur depletion does not follow the same pattern as other elements in dust grains ([White+2011](http://adsabs.harvard.edu/abs/2011AAS...21812923W)), and small sulfur compounds like H₂CS are detected in outflows where they are expected to form into more complex species ([Minh+2011](http://adsabs.harvard.edu/abs/2011ApJ...737L..25M)).\r\n\r\nGiven that sulfur and carbon have similar electronegativities and both have extensive chemistries, it is logical to consider heterocyclic sulfur-bearing PAH molecules in astrochemical studies, both experimentally and observationally. Vibrational wavelengths are expected to fall in the 6-9 µm region and at longer wavelengths, where it is well known that many observed emission bands are still poorly understood, with several unidentified or tentatively assigned lines remaining.","created_at":"2015-05-01T10:08:28.636Z","updated_at":"2015-05-14T21:28:20.848Z","zenodo_id":28346,"doi":"http://dx.doi.org/10.5281/zenodo.17292","subject":null,"tags":["astronomy","astrochemistry","molecular astrophysics","sulfur","hydrocarbons","pahs","interstellar medium"],"vote_count":2,"view_count":1,"score":2.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null}]