Detection of five C-13 isotopic species of HC5N in TMC-1

Takano, Shuro; Suzuki, Hiroko; Ohishi, Masatoshi; Ishikawa, Shinya; Kaifu, Norio; Hirahara, Yasuhiro; Masuda, Akimasa

doi:10.1086/185816

Cited by 46 publications

(98 citation statements)

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“…In TMC-1, the rotational temperature of various carbon-chain molecules ranges mostly from 4 to 8 K, which is lower than the gas kinetic temperature of 10 K (e.g., Kawaguchi et al 1991;Kalenskii et al 2004;Takano et al 1990). This means that the density of the emitting region is not high enough to thermalize the rotational level population to the gas kinetic temperature for most cases.…”

Section: High-excitation Lines Of Carbon-chain Moleculesmentioning

confidence: 94%

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Sakai

Hirota

et al. 2008

ApJ

188

273

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Section: High-excitation Lines Of Carbon-chain Moleculesmentioning

confidence: 94%

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Sakai

Hirota

et al. 2008

ApJ

188

273

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“…Takano et al (1998) CN] ratio to be 79 ± 11, 75 ± 10, and 55 ± 7 (1σ), respectively. Takano et al (1990) derived the 12 C/ 13 C ratios for the five 13 C species of HC 5 N to be 79-103. Recently, Langston & Turner (2007) However, the dilution has not been discussed seriously, although Sakai et al (2007a) considered an effect of the isotope selective photodissociation for the 13 CCS case.…”

Section: C Dilution In Cchmentioning

confidence: 99%

Abundance anomaly of the¹³C species of CCH

Sakai

Saruwatari

Sakai³

et al. 2010

A&A

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Aims. We have observed the N = 1−0 lines of CCH and its 13 C isotopic species toward a cold dark cloud, TMC-1 and a star-forming region, L1527, to investigate the 13 C abundances and formation pathways of CCH. Methods. The observations have been carried out with the IRAM 30 m telescope. Results. We have successfully detected the lines of 13 CCH and C 13 CH toward the both sources and found a significant intensity difference between the two 13 C isotopic species. The [C 13 CH]/[ 13 CCH] abundance ratios are 1.6 ± 0.4 (3σ) and 1.6 ± 0.1 (3σ) for TMC-1 and L1527, respectively. The abundance difference between C 13 CH and 13 CCH means that the two carbon atoms of CCH are not equivalent in the formation pathway. On the other hand, the [CCH]/[C 13 CH] and [CCH]/[ 13 CCH] ratios are evaluated to be larger than 170 and 250 toward TMC-1, and to be larger than 80 and 135 toward L1527, respectively. Therefore, both of the 13 C species are significantly diluted in comparison with the interstellar 12 C/ 13 C ratio of 60. The dilution is discussed in terms of a behavior of 13 C in molecular clouds.

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“…In the same year Avery et al (1976) reported the first interstellar detection of this carbon chain in the molecular cloud Sgr B2, where the 10.65 GHz line was observed. Since that time, the number of new HC 5 N sources and interstellar transitions has increased regularly, leading to the detection of emission lines also in the millimeter-wave (mm-wave) region (Winnewisser & Walmsley 1979), for the deuterated species (MacLeod et al 1981), and for the 13 C-containing isotopomers (Takano et al 1990). The study of the ground-state rotational spectrum of HC 5 N was extended to the mm-wave region by Winnewisser et al (1982), and then to the submm-wave region by Bizzocchi et al (2004).…”

Section: Introductionmentioning

confidence: 99%

Millimeter-wave spectroscopy of HC₅N in vibrationally excited states below 500 cm$\mathsf{^{-1}}$

Yamada

Esposti²,

Botschwina

et al. 2004

A&A

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Abstract. The rotational spectrum of the semistable HC 5 N molecule has been investigated in the millimeter-wave region for eight excited bending states which lie below 500 cm −1 , namely v 11 = 1, 2, 3, and 4, v 10 = 1, v 9 = 1, (v 10 = 1, v 11 = 1), and (v 10 = 1, v 11 = 2). Transitions up to J = 101 ← 100 were measured, reaching a frequency as high as 270 GHz. The set of spectroscopic constants determined in the present work makes it possible to predict with much improved accuracy the transition frequencies of millimeter-wave lines produced by vibrationally excited HC 5 N in hot core molecular sources and circumstellar shells. In addition, results of extensive CCSD(T) calculations are presented, which yield accurate term values for low-lying bending vibrational states.

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Detection of five C-13 isotopic species of HC5N in TMC-1

Cited by 46 publications

References 0 publications

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Abundance anomaly of the¹³C species of CCH

Millimeter-wave spectroscopy of HC₅N in vibrationally excited states below 500 cm$\mathsf{^{-1}}$

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Detection of five C-13 isotopic species of HC5N in TMC-1

Cited by 46 publications

References 0 publications

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Abundant Carbon‐Chain Molecules toward the Low‐Mass Protostar IRAS 04368+2557 in L1527

Abundance anomaly of the13C species of CCH

Millimeter-wave spectroscopy of HC5N in vibrationally excited states below 500 cm$\mathsf{^{-1}}$

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Abundance anomaly of the¹³C species of CCH

Millimeter-wave spectroscopy of HC₅N in vibrationally excited states below 500 cm$\mathsf{^{-1}}$