J/A+A/708/A312ivo://CDS.VizieR/J/A+A/708/A312CDSHayoz J.Bonse M.J.Garvin E.O.Cugno G.Dannert F.Kuehnle H.,De Rosa R.J.Agudo Berbel A.Cao Y.Orban de Xivry G.Stolker T.,Davies R.Absil O.Schmid H.M.Quanz S.P.Godoy N.Balmer W.O.,Bowler B.P.Palma-Bifani P.Currie T.Chauvin G.Agapito G.,Baruffolo A.Black M.Bonaglia M.Briguglio R.Carbonaro L.Cresci G.,Dallilar Y.Deysenroth M.Di Antonio I.Di Cianno A.Di Rico G.,Doelman D.Dolci M.Eisenhauer F.Esposito S.Fantinel D.Ferruzzi D.,Feuchtgruber H.Foerster Schreiber N.M.Gao X.Genzel R.Gillessen S.,Glauser A.M.Grani P.Hartl M.Henry D.Huber H.Keller C.,Kenworthy M.Kravchenko K.Lightfoot J.Lunney D.Lutz D.MacIntosh M.,Mannucci F.Ott T.Pearson D.Puglisi A.Rabien S.Rau C.Riccardi A.,Salasnich B.Shimizu T.Snik F.Sturm E.Tacconi L.Taylor W.,Valentini A.Waring C.Wiezorrek E.Xompero M.2026-05-04T07:43:19Z2026-04-23T08:55:17ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsinfrared-astronomyspectroscopyConstraining the link between the atmospheric composition of giant exoplanets and their formation history is a key goal of exoplanet studies. In particular, the atmospheric C/O ratio, metallicity, and CO isotopologue ratio - which are readily measurable with direct spectroscopic observations - are believed to be chemical tracers of the birth location of substellar and planetary companions. We aim to collect observational constraints for planet formation theories by performing a large and systematic survey of the atmospheric C/O ratio, metallicity, and isotopologue ratio. We collected new K-band moderate-resolution R=11000 spectroscopic observations of 13 directly-imaged planetary-mass companions spanning the molecular snowlines of CO_2_, CO, and CH4 and with masses 4-30MJ with VLT/ERIS/SPIFFIER. Additionally, we gathered a large portion of the available archival observations for these targets, amounting to 40 spectra and 140 photometric fluxes. We performed spectral fits using self-consistent grid models and freely parametrisable models. We obtained robust estimates of the key atmospheric parameters by aggregating the results from the different models, thereby reducing modelling systematics. Using molecular mapping, we detect H2O and CO in 12 of our targets, as well as ^13^CO in HR 2562 B. With our multimodel spectral fitting strategy, we obtain stellar to superstellar C/O ratios - ranging between 0.4 and 0.8 - and predominantly superstellar metallicities - between -0.5 and 1.5dex - across all targets. We measure a substantial enrichment of ^13^CO for HR 2562 B with ^12^CO/^13^CO=12.0^+4.5^_-3.3_. If corroborated by independent observations, it could indicate that the companion might have formed beyond the CO snowline and later migrated inwards to its current location. We find an anti-correlation (R=-0.58) between the atmospheric C/O ratio and the companion mass, consolidating previous results.2026A&A...708A.312Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A312CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A312https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A312http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A312https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/708/A312https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/708/A312http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/708/A312GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/708/A312/phot (List of photometric data for all 12 companions analysed in the paper (table E2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A312/phot?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A312/phot?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A312/phot?GETtext/xml+votable180.050000true34.842125-39.422916670.005555555555555556Cone search capability for table J/A+A/708/A312/speceris (List of ERIS/SPIFFIER spectroscopic data for all 12 companions analysed in the paper (table E1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A312/speceris?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A312/speceris?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A312/speceris?GETtext/xml+votable180.050000true34.842125-39.422916670.005555555555555556Cone search capability for table J/A+A/708/A312/specarch (List of archival spectroscopic data for all 12 companions analysed in the paper)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A312/specarch?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A312/specarch?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A312/specarch?GETtext/xml+votable180.050000true34.842125-39.422916670.0055555555555555566/20125 21386 25055 35268 36957 38937 39044 42958 42970 44352 44363https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/708/A312?format=asciiInfrareddefaultJ/A+A/708/A312/photList of photometric data for all 12 companions analysed in the paper (table E2)recnoRecord number assigned by the VizieR team. 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