Detections of long carbon chains CH3CCCCH, C6H, linear-C6H2 and C7H in the low-mass star forming region L1527

Araki, Mitsunori

Permalink

https://hdl.handle.net/2142/96802 Copy

Description

Title

Detections of long carbon chains CH3CCCCH, C6H, linear-C6H2 and C7H in the low-mass star forming region L1527

Author(s)

Araki, Mitsunori

Contributor(s)

• Tsukiyama, Koichi
• Kuze, Nobuhiko
• Oyama, Takahiro
• Yamamoto, Satoshi
• Sakai, Nami
• Takano, Shuro

Issue Date

2017-06-20

Keyword(s)

Astronomy

Abstract

Carbon chains in the warm carbon chain chemistry (WCCC) region has been searched in the 42--44 GHz region by using Green Bank 100 m telescope. Long carbon chains C$_{7}$H, C$_{6}$H, CH$_{3}$CCCCH, and linear-C$_{6}$H$_{2}$ and cyclic species C$_{3}$H and C$_{3}$H$_{2}$O have been detected in the low-mass star forming region L1527, performing the WCCC. C$_{7}$H was detected for the first time in molecular clouds. The column density of C$_{7}$H is derived to be $6.2 times 10^{10}$ cm$^{-2}$ by using the detected $J$ = 24.5--23.5 and 25.5--24.5 rotational lines. The $^{2}Pi_{1/2}$ electronic state of C$_{6}$H, locating 21.6 K above the $^{2}Pi_{3/2}$ electronic ground state, and the $K_a$ = 0 line of the para species of linear-C$_{6}$H$_{2}$ were also detected firstly in molecular clouds. The column densities of the $^{2}Pi_{1/2}$ and $^{2}Pi_{3/2}$ states of C$_{6}$H in L1527 were derived to be $1.6 times 10^{11}$ and $1.1 times 10^{12}$ cm$^{-2}$, respectively. The total column density of linear-C$_{6}$H$_{2}$ is obtained to be $1.86 times 10^{11}$ cm$^{-2}$. While the abundance ratios of carbon chains in between L1527 and the starless dark cloud Taurus Molecular Cloud-1 Cyanopolyyne Peak (TMC-1 CP) have a trend of decrease by extension of carbon-chain length, column densities of CH$_{3}$CCCCH and C$_{6}$H are on the trend. However, the column densities of linear-C$_{6}$H$_{2}$, and C$_{7}$H are as abundant as those of TMC-1 CP in spite of long carbon chain, i.e., they are not on the trend. The abundances of linear-C$_{6}$H$_{2}$ and C$_{7}$H show that L1527 is rich for long carbon chains as well as TMC-1 CP.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96802

DOI

https://doi.org/10.15278/isms.2017.TA06

Copyright and License Information

Copyright 2017 Mitsunori Araki

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