J/A+A/589/A78ivo://CDS.VizieR/J/A+A/589/A78doi:10.26093/cds/vizier.35890078CDSBiver N.Moreno R.Bockelee-Morvan D.Sandqvist Aa.Colom P.,Crovisier J.Lis D.C.Boissier J.Debout V.Paubert G.Milam S.,Hjalmarson A.Lundin S.Karlsson T.Battelino M.Frisk U.Murtagh D.,Odin team2017-05-28T11:49:28Z2016-04-15T14:54:33ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frcometsradio-astronomyradio-spectroscopyThe apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in March-April 2013 and January 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. We observed comet Lovejoy with the IRAM 30m telescope between 13 and 26 January 2015, and with the Odin submillimeter space observatory on 29 January - 3 February 2015. We detected 22 molecules and several isotopologues. The H216O and H218O production rates measured with Odin follow a periodic pattern with a period of 0.94 days and an amplitude of ~25%. The inferred isotope ratios in comet Lovejoy are ^16^O/^18^O=499+/-24 and D/H=1.4+/-0.4*10^-4^ in water, ^32^S/^34^S=24.7+/-3.5 in CS, all compatible with terrestrial values. The ratio ^12^C/^13^C=109+/-14 in HCN is marginally higher than terrestrial and ^14^N/^15^N=145+/-12 in HCN is half the Earth ratio. Several upper limits for D/H or ^12^C/^13^C in other molecules are reported. From our observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an Oort Cloud comet that is not larger than the terrestrial value. On the other hand, the observation of the same HDO line in the other Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous measurements of D/H in cometary water, this illustrates that a diversity in the D/H ratio and in the chemical composition, is present even within the same dynamical group of comets, suggesting that current dynamical groups contain comets formed at very different places or times in the early solar system.2016A&A...589A..78Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/589/A78CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/559/A48 : Mm-spectra of comets C/2001 Q2 and C/2002 T7J/A+A/564/L2 : CH3OH line parameters in comets ISON and LovejoyJ/A+A/566/L5 : C/2012 F6 (Lemmon) and C/2013 R1 spectra (Lovejoy)J/other/SciA/1.9 : C/2014 Q2 (Lovejoy) spectra (Biver+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/589/A78https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/589/A78http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/589/A78https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/589/A78https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/589/A78http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/589/A78GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapAssociated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/589/A78RadiodefaultJ/A+A/589/A78/listList of fits spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameComet namemeta.id;meta.maincharNxNumber of channelsmeta.numberintObs.DateObservation datetime.epoch;obscharDf0Lower value of frequency intervalHzinstr.bandwidthdoubleDf1Upper value of frequency intervalHzinstr.bandwidthdoubledfFrequency resolutionHzspect.resolutiondoubleFreqRest frequency of the transitionGHzem.freq;phys.atmol.transitiondoublesizeSize of FITS fileKibytephys.size;meta.fitsintspplot of spectrummeta.ref.urlcharfitsDownload the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory spmeta.id;meta.fitscharTitleTitle of the FITS filemeta.noteAssocDataAssociated Data web pagemeta.bib.pagechar