J/A+A/680/A25ivo://CDS.VizieR/J/A+A/680/A25doi:10.26093/cds/vizier/bc-n8/lcfCDSFatima M.Mueller H.S.P.Zingsheim O.Lewen F.Rivilla V.M.,Jimenez-Serra I.Martin-Pintado J.Schlemmer S.2026-07-03T06:35:35Z2023-12-04T08:39:07ZCDS support team

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

cds-question@unistra.frmolecular-cloudsinterstellar-mediumspectroscopymillimeter-astronomysubmillimeter-astronomyatomic-physicsIsobutene ((CH_3_)_2_C=CH_2_) is one of the four isomers of butene (C_4_H_8_). After the detection of propene (CH_3_CH=CH_2_) toward TMC-1, and also in the warmer environment of the solar-type protostellar system IRAS 16293-2422, one of the next alkenes, isobutene, is thus a promising candidate to be searched for in space. We aim to extend the limited line lists of the main isotopologue of isobutene from the microwave to the millimeter region to obtain a highly precise set of rest frequencies and to facilitate its detection in the interstellar medium.2023A&A...680A..25Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/680/A25CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/680/A25https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/680/A25http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/680/A25https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/680/A25https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/680/A25http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/680/A25GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapMillimeterdefaultJ/A+A/680/A25/c3h4Transitions included in the fit of isobutene ((CH3)2C=CH2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ'Upper state J quantum numberphys.atmol.configurationintKa'Upper state Ka quantum numberphys.mol.qnintKc'Upper state Kc quantum numberphys.mol.qnintJ"Lower state J quantum numberphys.atmol.configurationintKa"Lower state Ka quantum numberphys.mol.qnintKc"Lower state Kc quantum numberphys.mol.qnintFreqObsObserved transition frequencyMHzem.freqdouble(O-C)Observed minus calculated frequencyMHzem.freq;stat.fit.omcfloatUncerUncertainity usedMHzstat.errorfloatqq'(IS1,IS2) internal rotor components (1)meta.codeintwb? Weight of the component in group of linesphys.atmol.weightfloatnullableI(O-C)? Individual O-C residual for line consisting of several transitionsMHzstat.fit.residualfloatnullableNotesSource of data (2)meta.noteintJ/A+A/680/A25/056526*Catalogue file up to 1THz (J=99, T=300K) generated from ERHAM program, with additional blanksrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFreqPredicted frequencyMHzem.freqdoubleEst(O-C)Estimated errorMHzstat.errorfloatlogIntBase10 logarithm of the integrated intensitylog(nm**2.MHz)spect.line.intensityfloatDRDegrees of freedom in the rotational partition functionstat.fit.dofintEloLower state energycm**-1phys.energy;phys.atmol.leveldoubleGupUpper state degeneracyphys.electron.degenintTAGCDMS entry tagmeta.noteintJ'Upper state J quantum numberphys.atmol.configurationintKa'Upper state Ka quantum numberphys.mol.qnintKc'Upper state Kc quantum numberphys.mol.qnintq(IS1) internal rotor components (1)meta.codeintJ"Lower state J quantum numberphys.atmol.configurationintKa"Lower state Ka quantum numberphys.mol.qnintKc"Lower state Kc quantum numberphys.mol.qnintq'(IS2) internal rotor components (1)meta.codeint