Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

P (Space and Planetary Sciences ) » P-CG Complex & General

[P-CG23] Origin and evolution of materials in space

Sun. May 26, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Hitoshi Miura(Graduate School of Natural Sciences, Department of Information and Basic Science, Nagoya City University), Hideko Nomura(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Takafumi Ootsubo(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Aki Takigawa(Division of Earth and Planetary Science, Kyoto University)

[PCG23-P04] Laboratory Detection of New Absorption Bands of Interstellar-Molecule Candidate Thiophenoxy Radical

Haruka Sato1, Mayu Negishi1, *Mitsunori Araki1, Takahiro Oyama1, Koichi Tsukiyama1 (1.Department of Chemistry, Faculty of Science Division I, Tokyo University of Science)

Keywords:Interstellar molecule, Diffuse Interstellar Bands, DIBs, Cavity Ring Down, thiophenoxy radical

Diffuse Interstellar Bands (DIBs) are absorption bands detected in diffuse clouds by optical observations. Although ~600 DIBs have been found so far, only the five bands were assigned to the fullerene cation and the other bands are not identified yet. Recently, benzonitrile (C6H5CN) was detected in interstellar space by radio as the first aromatic compound [1]. Thus, thiophenoxy radical (C6H5S) is received much attentions as a candidate of DIBs, because sulfur is a dominant element of interstellar molecules. For this molecule, the origin band, which is a pure electronic transition without effects of molecular vibrations, was observed as the strongest band of the 2A2–X2B1 electronic transition [2,3]. However, our previous measurement of phenoxy radical (C6H5O) showed the strong vibronic bands with effects of molecular vibrations [4]. Thus, strong vibronic bands of C6H5S are expected because of similarity of the two molecules. We investigated the vibronic bands in the 473 – 519 nm region by Cavity Ring Down spectroscopy and detected them. The strongest vibronic band at 4850 Å was assigned to the 6a02 + 6b01 transition. This band is thought to be a candidate of DIB.

[1] McGuire et al. Science, 359, 202 (2018). [2] Shibuya et al., J. Chem. Phys. 121, 237 (1988). [3] Araki et al., Astronomical J. 148, 87 (2014). [4] Araki et al., Astronomical J. 150, 113 (2015).