J/A+A/667/A136ivo://CDS.VizieR/J/A+A/667/A136doi:10.26093/cds/vizier.36670136CDSVan Gelder M.L.Jaspers J.Nazari P.Ahmadi A.Van Dishoeck E.F.,Beltran M.T.Fuller G.A.Sanchez-monge A.Schilke P.2023-03-29T13:13:27Z2023-02-22T14:14:32ZCDS support team

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

cds-question@unistra.frastrophysical-masersradio-astronomyinterstellar-mediummillimeter-astronomysubmillimeter-astronomyThe deuteration of molecules forming in the ices such as methanol (CH_3_OH) is sensitive to the physical conditions during their formation in dense cold clouds and can be probed through observations of deuterated methanol in hot cores. The aim is to determine the D/H ratio of methanol for a large sample of 99 high-mass protostars and to link this to the physical conditions during the formation of methanol in the prestellar phases. Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) containing transitions of CH_3_OH, CH_2_DOH, CHD_2_OH, ^13^CH_3_OH, and CH_3_^18^OH are investigated. The column densities of CH_2_DOH, CHD_2_OH, and CH_3_OH are determined for all sources, where the column density of CH_3_OH is derived from optically thin ^13^C and ^18^O isotopologues. Consequently, the D/H ratio of methanol is derived taking statistical effects into account. Singly deuterated methanol (CH_2_DOH) is detected at the 3{sigma} level toward 25 of the 99 sources in our sample of the high-mass protostars. Including upper limits, the <D/H>_CH3OH_ ratio inferred from N_CH2DOH_/N_CH3OH_ was derived for 38 of the 99 sources and varies between ~10-3-10-2. Including other high-mass hot cores from the literature, the mean methanol D/H ratio is 1.1+/-0.7x10^-3^. This is more than one order of magnitude lower than what is seen for low-mass protostellar systems (2.2+/-1.2x10^-2^). Doubly deuterated methanol (CHD_2_OH) is detected at the 3{sigma} level toward 11 of the 99 sources. Including upper limits for 15 sources, the <D/H>_CH2DOH_ ratios derived from N_CH2DOH_/N_CH2DOH_ are more than two orders of magnitude higher than <D/H>_CH3OH_ with an average of 2.0+/-0.8x10^-1^ which is similar to what is found for low-mass sources. Comparison with literature GRAINOBLE models suggests that the high-mass prestellar phases are either warm (>20K) or live shorter than the free-fall timescale. In contrast, for low-mass protostars, both a low temperature of <15K and a prestellar phase timescale longer than the free-fall timescale are necessary. The <D/H>_CH3OH_ ratio drops by more than an order of magnitude between low-mass and high-mass protostars due to either a higher temperature during the prestellar phases or shorter prestellar phases. However, successive deuteration toward CHD_2_OH seems equally effective between low-mass and high-mass systems.2022A&A...667A.136Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/667/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/667/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/667/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/667/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/667/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/667/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/667/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/667/A136/tableb1 (Column densities of ^13^CH_3_OH, CH_3_^18^OH, CH_3_OH, CH_2_DOH, and CHD_2_OH and derived methanol D/H ratios)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/667/A136/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/667/A136/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/667/A136/tableb1?GETtext/xml+votable180.050000true276.7038333-12.44014170.0055555555555555565/7383 6/21504 29505 29508 30241 30258 30262 37343 37746 38024 39246 39404 41653 41655 41676-41677 41682 41684 41688 41770 41772 41777-41778 41781 41804 41814 42159 42381-42382 42390 42393 42396 42436 42441 43013 43024https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/667/A136?format=asciiMillimeterRadiodefaultJ/A+A/667/A136/tableb1Column densities of ^13^CH_3_OH, CH_3_^18^OH, CH_3_OH, CH_2_DOH, and CHD_2_OH and derived methanol D/H ratiosrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSourceSource namemeta.id;meta.maincharRAJ2000Right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Declination (12000) (1)pos.eq.dec;meta.mainphibeamBeam sizearcsecphys.angSize;instr.beamfloatTexExcitation temperatureKphys.atmol.excitationintn_Tex[3] Note on Tex (2)meta.notecharl_N13CH3OHLimit flag on N13CH3OHmeta.code.errorcharN13CH3OH^13^CH_3_OH column density (3)cm**-2phys.columnDensitydoublee_N13CH3OH? ^13^CH_3_OH column density errorcm**-2stat.errordoublenullablel_NCH318OHLimit flag on NCH318OHmeta.code.errorcharNCH318OHCH_3_^18^OH column density (3)cm**-2phys.columnDensitydoublee_NCH318OH? CH_3_^18^OH column density errorcm**-2stat.errordoublenullablel_NCH3OHLimit flag on NCH3OHmeta.code.errorcharNCH3OHCH_3_OH column density or lower limit of CH_3_OH column density (4)cm**-2phys.columnDensitydoublee_NCH3OH? CH_3_OH column density errorcm**-2stat.errordoublenullableNCH3OHu? Upper limit of NCH3OH interval (4)cm**-2time.interval;stat.maxdoublenullablel_NCH2DOHLimit flag on NCH2DOHmeta.code.errorcharNCH2DOHCH_2_DOH column density (3)cm**-2phys.columnDensitydoublee_NCH2DOH? CH_2_DOH column density errorcm**-2stat.errordoublenullablel_NCHD2OHLimit flag on NCHD2OHmeta.code.errorcharNCHD2OHCHD_2_OH column density (3)cm**-2phys.columnDensitydoublee_NCHD2OH? CHD_2_OH column density errorcm**-2stat.errordoublenullablel_<D/H>1Limit flag on <D/H>_CH3OH_meta.code.error;phys.abundchar<D/H>1? <D/H>_CH3OH_ using Eq. (2) of the paperphys.density;arith.ratiodoublenullablee_<D/H>1? <D/H>1 errorstat.error;phys.abunddoublenullablel_<D/H>2Limit flag on <D/H>_CH3OH_meta.code.error;phys.abundchar<D/H>2? <D/H>_CH3OH_ using Eq. (3)of the paperphys.density;arith.ratiodoublenullablee_<D/H>2? <D/H>2 errorstat.error;phys.abunddoublenullable