Interstellar $^{\mathsf{12}}$C/$^{\mathsf{13}}$C from CH<sup>+</sup>absorption lines: results from an extended survey

Stahl, O.; Casassus, S.; Wilson, Thomas L.

doi:10.1051/0004-6361:20078747

Cited by 30 publications

(32 citation statements)

References 32 publications

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“…The results for the each LOS are summarized in Table 1 where we have separated the absorption components in the velocity range of the star-forming regions from those originating in unrelated Galactic foreground gas. The 13 CH + and 12 CH + column densities of the foreground gas on the W49N LOS provide a lower limit of the isotopic ratio [ 12 CH + ]/[ 13 CH + ] > 35.5, consistent with the results of Casassus et al (2005); Stahl et al (2008). Three N(CH + )/N(HCO + ) ratios, computed using the observed N(HCO + ) values of Godard et al (2010), are found to be scattered by more than a factor 10.…”

Section: Line Profiles Analysis and Resultssupporting

confidence: 84%

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

Falgarone¹,

Godard

Cernicharo

et al. 2010

A&A

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We report the detection of the ground-state rotational transition of the methylidyne cation CH + and its isotopologue 13 CH + toward the remote massive star-forming regions W33A, W49N, and W51 with the HIFI instrument onboard the Herschel satellite. Both lines are seen only in absorption against the dust continuum emission of the star-forming regions. The CH + absorption is saturated over almost the entire velocity ranges sampled by the lines-of-sight that include gas associated with the star-forming regions (SFR) and Galactic foreground material. The CH + column densities are inferred from the optically thin components. A lower limit of the isotopic ratio [ 12 CH + ]/[ 13 CH + ] > 35.5 is derived from the absorptions of foreground material toward W49N. The column density ratio, N(CH + )/N(HCO + ), is found to vary by at least a factor 10, between 4 and >40, in the Galactic foreground material. Line-of-sight 12 CH + average abundances relative to total hydrogen are estimated. Their average value, N(CH + )/N H > 2.6 × 10 −8 , is higher than that observed in the solar neighborhood and confirms the high abundances of CH + in the Galactic interstellar medium. We compare this result to the predictions of turbulent dissipation regions (TDR) models and find that these high abundances can be reproduced for the inner Galaxy conditions. It is remarkable that the range of predicted N(CH + )/N(HCO + ) ratios, from 1 to ∼50, is comparable to that observed.

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Section: Line Profiles Analysis and Resultssupporting

confidence: 84%

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

Falgarone¹,

Godard

Cernicharo

et al. 2010

A&A

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“…The 12 C/ 13 C ratio of the solar system (89 ± 1) (Wyckoff et al 2000;Clayton & Nittler 2004) is higher than the interstellar ratio in the solar neighborhood (76 ± 7) (Stahl et al 2008). This difference can be explained by the high 13 C/ 12 C ratio in winds from red giant branch and AGB stars (Timmes et al 1995;Milam et al 2005), although chemical inhomogeneities in the ISM may also be important (Stahl et al 2008).…”

Section: Discussionmentioning

confidence: 99%

“…This difference can be explained by the high 13 C/ 12 C ratio in winds from red giant branch and AGB stars (Timmes et al 1995;Milam et al 2005), although chemical inhomogeneities in the ISM may also be important (Stahl et al 2008). The present-day C and O isotopic composition of the ISM at the Galactocentric location of the Sun's birth is consistent with mixing of average AGB winds with the ISM 4.6 Gyr ago (represented by the solar system) (Figure 3).…”

Section: Discussionmentioning

confidence: 99%

On the Oxygen Isotopic Composition of the Solar System

Gaidos

Krot

Huss

2009

ApJ

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The 18 O/ 17 O ratio of the solar system is 5.2 while that of the interstellar medium (ISM) and young stellar objects is ∼4. This difference cannot be explained by pollution of the Sun's natal molecular cloud by 18 O-rich supernova ejecta because (1) the necessary B-star progenitors live longer than the duration of star formation in molecular clouds, (2) the delivery of ejecta gas is too inefficient and the amount of dust in supernova ejecta is too small compared to the required pollution (2% of total mass or ∼20% of oxygen), and (3) the predicted amounts of concomitant short-lived radionuclides (SLRs) conflicts with the abundances of 26 Al and 41 Ca in the early solar system. Proposals for the introduction of 18 O-rich material must also be consistent with any explanation for the origin of the observed slope-one relationship between 17 O/ 16 O and 18 O/ 16 O in the high-temperature components of primitive meteorites. The difference in 18 O/ 17 O ratios can be explained by enrichment of the ISM by the 17 O-rich winds of asymptotic giant branch (AGB) stars, the sequestration of comparatively 18 O-rich gas from star-forming regions into long-lived, low-mass stars, and a monotonic decrease in the 18 O/ 17 O ratio of interstellar gas. At plausible rates of star formation and gas infall, Galactic chemical evolution does not follow a slope-one line in a three-isotope plot, but instead moves along a steeper trajectory toward an 17 O-rich state. Evolution of the ISM and star-forming gas by AGB winds also explains the difference in the carbon isotope ratios of the solar system and ISM.

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“…Gredel 1997;Stahl et al 2008, and references therein). In contrast, being much less affected by interstellar extinction, radio/submm and near infrared absorption observations, e.g.…”

Section: (Sub)millimeter Spectroscopy Of Diffuse Interstellar Cloudsmentioning

confidence: 99%

Submillimeter absorption from SH⁺, a new widespread interstellar radical,¹³CH⁺and HCl

Menten

Wyrowski

Беллоче

et al. 2010

A&A

118

104

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We have used the Atacama Pathfinder Experiment 12 m telescope (APEX) to carry out an absorption study of submillimeter wavelength rotational ground-state lines of H 35 Cl, H 37 Cl, 13 CH + , and, for the first time, of the SH + radical (sulfoniumylidene or sulfanylium). We detected the quartet of ground-state hyperfine structure lines of SH + near 683 GHz with the CHAMP+ array receiver against the strong continuum source Sagittarius B2, which is located close to the center of our Galaxy. In addition to absorption from various kinematic components of Galactic center gas, we also see absorption at the radial velocities belonging to intervening spiral arms. This demonstrates that SH + is a ubiquitous component of the diffuse interstellar medium. We do not find clear evidence for other SH + lines we searched for, which is partially due to blending with lines from other molecules. In addition to SH + , we observed absorption from H 35 Cl, H 37 Cl, and 13 CH + . The observed submillimeter absorption is compared in detail with absorption in 3 mm transitions of H 13 CO + and c-C 3 H 2 and the CO J = 1−0 and 3−2 transitions.

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Interstellar $^{\mathsf{12}}$C/$^{\mathsf{13}}$C from CH⁺absorption lines: results from an extended survey

Cited by 30 publications

References 32 publications

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

On the Oxygen Isotopic Composition of the Solar System

Submillimeter absorption from SH⁺, a new widespread interstellar radical,¹³CH⁺and HCl

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Interstellar $^{\mathsf{12}}$C/$^{\mathsf{13}}$C from CH+absorption lines: results from an extended survey

Cited by 30 publications

References 32 publications

CH+(1–0) and13CH+(1–0) absorption lines in the direction of massive star-forming regions

CH+(1–0) and13CH+(1–0) absorption lines in the direction of massive star-forming regions

On the Oxygen Isotopic Composition of the Solar System

Submillimeter absorption from SH+, a new widespread interstellar radical,13CH+and HCl

Contact Info

Product

Resources

About

Interstellar $^{\mathsf{12}}$C/$^{\mathsf{13}}$C from CH⁺absorption lines: results from an extended survey

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

CH⁺(1–0) and¹³CH⁺(1–0) absorption lines in the direction of massive star-forming regions

Submillimeter absorption from SH⁺, a new widespread interstellar radical,¹³CH⁺and HCl