CN and CCH derivatives of ethylene and ethane: Confirmation of the detection of CH$_3$CH$_2$CCH in TMC-1

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Hauptverfasser: Cernicharo, J., Tercero, B., Agúndez, M., Cabezas, C., Fuentetaja, R., Marcelino, N., de Vicente, P.
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Veröffentlicht: 2024
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author Cernicharo, J.
Tercero, B.
Agúndez, M.
Cabezas, C.
Fuentetaja, R.
Marcelino, N.
de Vicente, P.
author_facet Cernicharo, J.
Tercero, B.
Agúndez, M.
Cabezas, C.
Fuentetaja, R.
Marcelino, N.
de Vicente, P.
contents We present a study of CH$_3$CH$_2$CCH, CH$_3$CH$_2$CN, CH$_2$CHCCH, and CH$_2$CHCN in TMC-1 using the QUIJOTE$^1$ line survey. We confirm the presence of CH$_3$CH$_2$CCH in TMC-1, which was previously reported as tentative by our group. From a detailed study of the ethynyl and cyanide derivatives of CH$_2$CH$_2$ and CH$_3$CH$_3$ in TMC-1, we found that the CH$_2$CHCCH/CH$_2$CHCN and CH$_3$CH$_2$CCH/CH$_3$CH$_2$CN abundance ratios are 1.5$\pm$0.1 and 4.8$\pm$0.5, respectively. The derived CH$_2$CHCCH/CH$_3$CH$_2$CCH abundance ratio is 15.3$\pm$0.8, and that of CH$_2$CHCN over CH$_3$CH$_2$CN is 48$\pm$5. All the single substituted isotopologs of vinyl cyanide have been detected, and we found that the first and second carbon substitutions in CH$_2$CHCN provide a $^{12}$C/$^{13}$C ratio in line with that found for other three-carbon bearing species such as HCCNC and HNCCC. However, the third $^{13}$C isotopolog, CH$_2$CH$^{13}$CN, presents an increase in its abundance similar to that found for HCCCN. Finally, we observed eight $b$-type transitions of CH$_2$CHCN, and we find that their intensity cannot be fitted adopting the dipole moment $μ_b$ derived previously. These transitions involve the same rotational levels as those of the $a$-type transitions. From their intensity, we obtain $μ_b$=0.80$\pm$0.03\,D, which is found to be in between earlier values derived in the laboratory using intensity measurements or the Stark effect. Our chemical model indicates that the abundances of CH$_3$CH$_2$CCH, CH$_3$CH$_2$CN, CH$_2$CHCCH, and CH$_2$CHCN observed in TMC-1 can be explained in terms of gas-phase reactions.
format Preprint
id arxiv_https___arxiv_org_abs_2404_07585
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle CN and CCH derivatives of ethylene and ethane: Confirmation of the detection of CH$_3$CH$_2$CCH in TMC-1
Cernicharo, J.
Tercero, B.
Agúndez, M.
Cabezas, C.
Fuentetaja, R.
Marcelino, N.
de Vicente, P.
Astrophysics of Galaxies
We present a study of CH$_3$CH$_2$CCH, CH$_3$CH$_2$CN, CH$_2$CHCCH, and CH$_2$CHCN in TMC-1 using the QUIJOTE$^1$ line survey. We confirm the presence of CH$_3$CH$_2$CCH in TMC-1, which was previously reported as tentative by our group. From a detailed study of the ethynyl and cyanide derivatives of CH$_2$CH$_2$ and CH$_3$CH$_3$ in TMC-1, we found that the CH$_2$CHCCH/CH$_2$CHCN and CH$_3$CH$_2$CCH/CH$_3$CH$_2$CN abundance ratios are 1.5$\pm$0.1 and 4.8$\pm$0.5, respectively. The derived CH$_2$CHCCH/CH$_3$CH$_2$CCH abundance ratio is 15.3$\pm$0.8, and that of CH$_2$CHCN over CH$_3$CH$_2$CN is 48$\pm$5. All the single substituted isotopologs of vinyl cyanide have been detected, and we found that the first and second carbon substitutions in CH$_2$CHCN provide a $^{12}$C/$^{13}$C ratio in line with that found for other three-carbon bearing species such as HCCNC and HNCCC. However, the third $^{13}$C isotopolog, CH$_2$CH$^{13}$CN, presents an increase in its abundance similar to that found for HCCCN. Finally, we observed eight $b$-type transitions of CH$_2$CHCN, and we find that their intensity cannot be fitted adopting the dipole moment $μ_b$ derived previously. These transitions involve the same rotational levels as those of the $a$-type transitions. From their intensity, we obtain $μ_b$=0.80$\pm$0.03\,D, which is found to be in between earlier values derived in the laboratory using intensity measurements or the Stark effect. Our chemical model indicates that the abundances of CH$_3$CH$_2$CCH, CH$_3$CH$_2$CN, CH$_2$CHCCH, and CH$_2$CHCN observed in TMC-1 can be explained in terms of gas-phase reactions.
title CN and CCH derivatives of ethylene and ethane: Confirmation of the detection of CH$_3$CH$_2$CCH in TMC-1
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2404.07585