The (Cn)-N-14/(Cn)-N-15 Ratio in Diffuse Molecular Clouds

dc.contributor.utaustinauthorLambert, D. L.en_US
dc.creatorRitchey, A. M.en_US
dc.creatorFederman, S. R.en_US
dc.creatorLambert, David L.en_US
dc.date.accessioned2016-10-28T19:37:15Z
dc.date.available2016-10-28T19:37:15Z
dc.date.issued2015-05en_US
dc.description.abstractWe report the first detection of (CN)-N-15 in diffuse molecular gas from a detailed examination of CN absorption lines in archival spectra, obtained with the Ultraviolet and Visual Echelle Spectrograph of the Very Large Telescope of stars probing local diffuse clouds. Absorption from the (CN)-N-15 isotopologue is confidently detected ( at greater than or similar to 4 sigma) in three out of the four directions studied and appears as a very weak feature between the main (12) CN and (CN)-C-13 absorption components. Column densities for each CN isotopologue are determined through profile fitting, after accounting for weak additional line-of-sight components of (CN)-C-12, which are seen in the absorption profiles of CH and CH+ as well. The weighted mean value of N-14/(CN)-N-15 for the three sight lines with detections of (CN)-N-15 is 274 +/- 18. Since the diffuse molecular clouds toward our target stars have relatively high gas kinetic temperatures and relatively low visual extinctions, their N-14/(CN)-N-15 ratios should not be affected by chemical fractionation. The mean N-14/(CN)-N-15 ratio that we obtain should therefore be representative of the ambient N-14/N-15 ratio in the local interstellar medium. Indeed, our mean value agrees well with that derived from millimeter-wave observations of CN, HCN, and HNC in local molecular clouds.en_US
dc.description.departmentMcDonald Observatoryen_US
dc.description.sponsorshipNASA NNX10AD80Gen_US
dc.description.sponsorshipKenilworth Fund of the New York Community Trusten_US
dc.description.sponsorshipRobert A. Welch Foundation of Houston, TX F-634en_US
dc.identifierdoi:10.15781/T2HT2GF2B
dc.identifier.citationRitchey, Adam M., Steven R. Federman, and David L. Lambert. "The C14N/C15N Ratio in Diffuse Molecular Clouds." The Astrophysical Journal Letters, Vol. 804, No. 1 (May, 2015): L3.en_US
dc.identifier.doi10.1088/2041-8205/804/1/l3en_US
dc.identifier.issn2041-8205en_US
dc.identifier.urihttp://hdl.handle.net/2152/43056
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journal Lettersen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectastrochemistryen_US
dc.subjectism: lines and bandsen_US
dc.subjectism: moleculesen_US
dc.subjectb-2-sigma(+)-x-2-sigma(+) violet systemsen_US
dc.subjectgalactic chemical evolutionen_US
dc.subjecta(2)pi-x-2-sigma(+) reden_US
dc.subjectisotope ratiosen_US
dc.subjectcno isotopesen_US
dc.subjectmilky-wayen_US
dc.subjectabundancesen_US
dc.subjectgalaxyen_US
dc.subjectcoen_US
dc.subjectnucleosynthesisen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleThe (Cn)-N-14/(Cn)-N-15 Ratio in Diffuse Molecular Cloudsen_US
dc.typeArticleen_US

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