Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ===== On Sulfur-terminated Carbon Chain Molecules CnS in Space ===== ==== Thioxoethenylidene, C2S, and Thioxopropadienylidene, C3S ==== N. Kaifu, H. Suzuki, M. Ohishi, T. Miyaki, S.-I. Ishikawa, T. Kasuga, M. Morimoto, and S. Saito\\ reported on the\\ **[[https://ui.adsabs.harvard.edu/abs/1987ApJ...317L.111K|Detection of Intense Unidentified Lines in TMC-1]]**\\ //Astrophys. J.// **317**, L111–L114 (1987);\\ obtained in the course of a molecular line survey carried out with the 45 m Nobeyama telescope which ultimately covered the 8 – 50 GHz range.\\ \\ Laboratory spectroscopic investigations by\\ S. Saito, K. Kawaguchi, S. Yamamoto, M. Ohishi, H. Suzuki, and N. Kaifu\\ lead to the\\ **[[https://ui.adsabs.harvard.edu/abs/1987ApJ...317L.115S|Laboratory Detection and Astronomical Identification of a New Free Radical, CCS <sup>3</sup>Σ<sup>–</sup>]]**\\ //Astrophys. J.// **317**, L115–L118 (1987).\\ Four lines from the line survey mentioned above were assigned to C<sub>2</sub>S. These were the //N<sub>J</sub>// = 1<sub>2</sub> – 2<sub>1</sub>, 3<sub>3</sub> – 2<sub>2</sub>, 4<sub>3</sub> – 3<sub>2</sub>, and 3<sub>4</sub> – 2<sub>3</sub> transitions at 22344, 38866, 43981, and 45379 MHz, respectively. Please note: the labeling of the 2<sub>1</sub> level follows that of the CDMS catalog entry. This level is labeled 0<sub>1</sub> in the original work.\\ The authors also assigned several U-lines from two molecular line surveys of Sagittarius B2 in the 3 and 2 mm regions to C<sub>2</sub>S.\\ Finally, the CC<sup>34</sup>S isotopolog was also detected toward TMC-1 by its 1<sub>2</sub> – 2<sub>1</sub> transition at 21930 MHz.\\ \\ In addition, laboratory spectroscopic investigations by\\ S. Yamamoto, S. Saito, K. Kawaguchi, N. Kaifu, and H. Suzuki\\ lead to the\\ **[[https://ui.adsabs.harvard.edu/abs/1987ApJ...317L.119Y|Laboratory Detection of a New Carbon-chain Molecule C<sub>3</sub>S and its Astronomical Identification]]**\\ //Astrophys. J.// **317**, L119–L121 (1987).\\ The //J// = 4 – 3, 7 – 6, and 8 – 7 transitions were identified at 23123, 40465, and 46246 MHz, respectively. ==== Additional information on C2S ==== C<sub>2</sub>S, along with C<sub>3</sub>S, were also detected with the IRAM 30 m telescope in the circumstellar envelope of the carbon-rich late-type star CW Leo, also known as IRC +10216 in the course of a molecular line survey in the 3 and 2 mm regions by\\ J. Cernicharo, M. Guélin, H. Hein, and C. Kahane,\\ **[[https://ui.adsabs.harvard.edu/abs/1987A%26A...181L...9C|Sulfur in IRC +10216]]**\\ //Astron. Astrophys.// **181**, L9–L12 (1987).\\ \\ C<sub>2</sub>S was also seen toward several translucent clouds, albeit in only the lower energy transition of two by\\ B. E. Turner, H.-H. Lee, and E. Herbst,\\ **[[https://doi.org/10.1086/313077|The Physics and Chemistry of Small Translucent Molecular Clouds.\\ IX. Acetylenic Chemistry]]**\\ //Astrophys. J. Suppl. Ser.// **115**, 91–118 (1998).\\ \\ The two <sup>13</sup>C isotopomers were detected with the Nobeyama 45 m telescope toward TMC-1 by\\ N. Sakai, M. Ikeda, M. Morita, T. Sakai, S. Takano, Y. Osamura, and S. Yamamoto,\\ **[[https://doi.org/10.1086/518595|Production Pathways of CCS and CCCS Inferred from Their <sup>13</sup>C Isotopic Species]]**\\ //Astrophys. J.// **663**, 1174–1179 (2007).\\ The C<sup>13</sup>CS isotopolog is highly depleted, and it has not been detected in L1521E, whereas <sup>13</sup>CCS was seen. ==== Additional information on C3S ==== C<sub>3</sub>S, along with C<sub>2</sub>S, were also detected with the IRAM 30 m telescope in the circumstellar envelope of the carbon-rich late-type star CW Leo, also known as IRC +10216 in the course of a molecular line survey in the 3 and 2 mm region by\\ J. Cernicharo, M. Guélin, H. Hein, and C. Kahane,\\ **[[https://ui.adsabs.harvard.edu/abs/1987A%26A...181L...9C|Sulfur in IRC +10216]]**\\ //Astron. Astrophys.// **181**, L9–L12 (1987). The detection of the <sup>34</sup>S isotopolog in the course of the Nobeyama 45 m line survey was mentioned first by\\ M. Ohishi and N. Kaifu,\\ **[[https://doi.org/10.1039/a801058g|Chemical and Physical Evolution of Dark Clouds. Molecular Spectral Line Survey toward TMC-1]]**\\ //Faraday Discuss.// **190**, 205–216 (1998). C<sub>3</sub>S was deteceted very recently in a warm cloud by\\ B. Tercero, J. Cernicharo, J. R. Pardo, and J. R. Goicoechea,\\ **[[https://doi.org/10.1051/0004-6361/200913501|A line confusion limited millimeter survey of Orion KL\\ I. Sulfur carbon chains]]**\\ //Astron. Astrophys.// **517**, Art. No. A96 (2010). ---- ==== Information on thioxopentatetraenylidene, C5S ==== M. Agúndez, J. Cernicharo, and M. Guélin\\ reported on\\ **[[https://doi.org/10.1051/0004-6361/201424542|New molecules in IRC +10216: confirmation of C<sub>5</sub>S and tentative identification of MgCCH, NCCP, and SiH<sub>3</sub>CN]]**\\ //Astron. Astrophys.// **570**, Art. No. A45 (2014).\\ The //J// + 1 → //J// transitions with //J// = 43, 44, and 45 of C<sub>5</sub>S were identified in the course of a 3 mm line survey with the IRAM 30 m telescope near 81.2, 83.0, and 84.9 GHz. The first transition is blended. The almost similar column densities between two carbon chain molecules, here C<sub>5</sub>S and C<sub>3</sub>S, are very unusual, though not unprecedented.\\ \\ M. B. Bell, L. W. Avery, and P. A. Feldman\\ had reported on\\ **[[https://ui.adsabs.harvard.edu/abs/1993ApJ...417L..37B|C<sub>3</sub>S and C<sub>5</sub>S in IRC +10216]]**\\ //Astrophys. J.// **417**, L37–L40 (1993).\\ A line observed with the NRAO 43 m telecope near 24.0 GHz in the course of a molecular line survey was assigned to the //J// = 13 – 12 transition of C<sub>5</sub>S. The authors state in the abstract: "Assuming the observed feature is due to C<sub>5</sub>S, we find that //N//(C<sub>5</sub>S)///N//(C<sub>3</sub>S) ≈ 0.5." Confirmation of this finding or identification of further transitions at shorter wavelengths will be useful.\\ \\ The molecule was recently also identified in TMC-1 by\\ J. Cernicharo, C. Cabezas, M. Agúndez, B. Tercero, J. R. Pardo, N. Marcelino, J. D. Gallego, F. Tercero, J. A. López-Pérez, and P. de Vicente\\ **[[https://doi.org/10.1051/0004-6361/202140642|TMC-1, the starless core sulfur factory: Discovery of NCS, HCCS, H<sub>2</sub>CCS, H<sub>2</sub>CCCS, and C<sub>4</sub>S and detection of C<sub>5</sub>S]]**\\ //Astron. Astrophys.// **648**, Art. No. L3 (2021).\\ C<sub>5</sub>S was identified through 5 rotational transitions with //J"// = 16 to 20 and with modest to good signal-to-noise ratio (one slightly blended, one severely blended) in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope between 32.8 and 49.2 GHz. See below for statements on the column densities.\\ ---- ==== Information on C4S ==== J. Cernicharo, C. Cabezas, M. Agúndez, B. Tercero, J. R. Pardo, N. Marcelino, J. D. Gallego, F. Tercero, J. A. López-Pérez, and P. de Vicente\\ reported on\\ **[[https://doi.org/10.1051/0004-6361/202140642|TMC-1, the starless core sulfur factory: Discovery of NCS, HCCS, H<sub>2</sub>CCS, H<sub>2</sub>CCCS, and C<sub>4</sub>S and detection of C<sub>5</sub>S]]**\\ //Astron. Astrophys.// **648**, Art. No. L3 (2021).\\ C<sub>4</sub>S was identified through for fine structure transitions with //N"// = 9 to 12 and //J// = //N// + 1 and with moderate to good signal-to-noise ratio (one slightly blended, one severely blended) in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope between 32.8 and 49.2 GHz. The column density of C<sub>4</sub>S is slightly lower than that of C<sub>5</sub>S, and about factors of 340 and 1350 lower than those of C<sub>3</sub>S and C<sub>2</sub>S, respectively. ---- Contributor(s): H. S. P. Müller; 09, 2012; 07, 2018; 09, 2020; 04, 2021 ---- molecules/ism/c2_3s.txt Last modified: 2021/12/20 12:48by mueller