Deuterated interstellar and circumstellar molecules: D/H ratio and dominant formation processes

Etim, Emmanuel E.; Akpan, N. I.; Adelagun, R. A. O.; Lawal, U.; Khanal, Govinda Prasad

doi:10.1007/s12648-020-01747-x

Cited by 2 publications

(2 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We further introduce exchange reactions of C 3 H + with HD and D 2 , which have been studied by and , as displayed in Table 5. We estimate the endothermicity for the reverse reactions from the values reported for the cyclic and the linear isomers of C 3 H and C 3 D (Etim et al 2020).…”

Section: Chemical Modelmentioning

confidence: 99%

First detection of doubly deuterated methyl acetylene (CHD₂CCH and CH₂DCCD)

Agúndez

Roueff

Cabezas

et al. 2021

A&A

View full text Add to dashboard Cite

We report the first detection in space of the two doubly deuterated isotopologues of methyl acetylene. The species CHD2CCH and CH2DCCD were identified in the dense core L483 through, respectively, nine and eight rotational lines in the 72–116 GHz range using the 30 m telescope of the Institut de Radioastronomie Millimétrique (IRAM). We combined the astronomical frequencies observed here with laboratory frequencies from the literature measured in the 29–47 GHz range to derive more accurate spectroscopic parameters for the two isotopologues. We derive beam-averaged column densities of (2.7 ± 0.5) × 1012 cm−2 for CHD2CCH and (2.2 ± 0.4) × 1012 cm−2 for CH2DCCD, which translate to abundance ratios of CH3CCH/CHD2CCH = 34 ± 10 and CH3CCH/CH2DCCD = 42 ± 13. The doubly deuterated isotopologues of methyl acetylene are only a few times less abundant than the singly deuterated ones, specifically around 2.4 times less abundant than CH3CCD. The abundances of the different deuterated isotopologues with respect to CH3CCH are reasonably accounted for by a gas-phase chemical model in which deuteration occurs from the precursor ions C3H6D+ and C3H5D+, when the ortho-to-para ratio of molecular hydrogen is sufficiently low. This points to gas-phase chemical reactions, rather than grain-surface processes, as being responsible for the formation and deuterium fractionation of CH3CCH in L483. The abundance ratios CH2DCCH/CH3CCD = 3.0 ± 0.9 and CHD2CCH/CH2DCCD = 1.25 ± 0.37 observed in L483 are consistent with the statistically expected values of three and one, respectively, with the slight overabundance of CHD2CCH compared to CH2DCCD being well explained by the chemical model.

show abstract

Section: Chemical Modelmentioning

confidence: 99%

First detection of doubly deuterated methyl acetylene (CHD₂CCH and CH₂DCCD)

Agúndez

Roueff

Cabezas

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…We further introduce exchange reactions of C 3 H + with HD and D 2 , which have been studied by ; as displayed in Table 5. We estimate the endothermicity for the reverse reactions from the values reported for the cyclic and the linear isomers of C 3 H and C 3 D (Etim et al 2020).…”

Section: Chemical Modelmentioning

confidence: 99%

First detection of doubly deuterated methyl acetylene (CHD2CCH and CH2DCCD)

Agundez,

Roueff,

Cabezas

et al. 2021

Preprint

View full text Add to dashboard Cite

We report the first detection in space of the two doubly deuterated isotopologues of methyl acetylene. The species CHD 2 CCH and CH 2 DCCD were identified in the dense core L483 through nine and eight, respectively, rotational lines in the 72-116 GHz range using the IRAM 30m telescope. The astronomical frequencies observed here were combined with laboratory frequencies from the literature measured in the 29-47 GHz range to derive more accurate spectroscopic parameters for the two isotopologues. We derive beam-averaged column densities of (2.7 ± 0.5) × 10 12 cm −2 for CHD 2 CCH and (2.2 ± 0.4) × 10 12 cm −2 for CH 2 DCCD, which translate to abundance ratios CH 3 CCH/CHD 2 CCH = 34 ± 10 and CH 3 CCH/CH 2 DCCD = 42 ± 13. The doubly deuterated isotopologues of methyl acetylene are only a few times less abundant than the singly deuterated ones, concretely around 2.4 times less abundant than CH 3 CCD. The abundances of the different deuterated isotopologues with respect to CH 3 CCH are reasonably accounted for by a gas-phase chemical model in which deuteration occurs from the precursor ions C 3 H 6 D + and C 3 H 5 D + , when the ortho-to-para ratio of molecular hydrogen is sufficiently low. This points to gas-phase chemical reactions, rather than grain-surface processes, as responsible for the formation and deuterium fractionation of CH 3 CCH in L483. The abundance ratios CH 2 DCCH/CH 3 CCD = 3.0 ± 0.9 and CHD 2 CCH/CH 2 DCCD = 1.25 ± 0.37 observed in L483 are consistent with the statistically expected values of three and one, respectively, with the slight overabundance of CHD 2 CCH compared to CH 2 DCCD being well explained by the chemical model.

show abstract

Deuterated interstellar and circumstellar molecules: D/H ratio and dominant formation processes

Cited by 2 publications

References 46 publications

First detection of doubly deuterated methyl acetylene (CHD₂CCH and CH₂DCCD)

First detection of doubly deuterated methyl acetylene (CHD₂CCH and CH₂DCCD)

First detection of doubly deuterated methyl acetylene (CHD2CCH and CH2DCCD)

Contact Info

Product

Resources

About