J/A+A/703/A199ivo://CDS.VizieR/J/A+A/703/A199CDSEitner P.Bergemann M.Hoppe R.Storm N.Lipatova V.Glover S.C.O.,Klessen R.S.Nordlund A.Popovas A.2026-03-02T06:25:50Z2025-11-18T11:22:42ZCDS support team

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

cds-question@unistra.frastronomical-modelschemical-abundanceschemically-peculiar-starsUnderstanding the origin and evolution of carbon-enhanced metal-poor (CEMP) stars is key to tracing the early chemical enrichment of the Galaxy. In this work, we investigate how physically realistic 3D radiation-hydrodynamics (RHD), carbon-enhanced model atmospheres affect the inferred carbon abundances in CEMP stars, and assess the implications for their classification and for the Galactic chemical evolution (GCE). We pay particular attention to the systematic biases introduced by traditional 1D hydrostatic equilibrium (HE) models. We use the M3DIS code to compute 3D RHD model atmospheres for main-sequence and sub-giant stars spanning a wide range of metallicities and carbon enhancements. Synthetic spectra of the CH G-band are calculated using full 3D radiative transfer, and compared to spectra from classical 1D HE MARCS models. We derive abundance corrections and apply them to a large literature sample of metal-poor stars from the SAGA database to quantify systematic effects on the carbon abundance distribution and CEMP classification. Our new 3D CEMP models predict significantly cooler upper atmospheric layers than present in 1D HE models, resulting in stronger CH absorption and lower inferred carbon abundances by up to -0.9dex at the lowest metallicities. Carbon enhancement in the atmosphere itself increases molecular opacities and leads to radiative re-heating, which partly offsets the adiabatic cooling in 3D models and reduces the magnitude of 3D-1D abundance corrections. Applying these corrections lowers the CEMP fraction by up to 20% below [Fe/H]=-3, and furthermore alters the relative contribution of CEMP sub-classes. In particular, the fraction of CEMP-no stars increases while the number of stars classified as CEMP-r/s decreases, owing to the downward revision of absolute carbon abundances. These changes bring the Galactic carbon abundance distribution into better agreement with GCE models that assume a contribution from faint supernovae of 20%. Physically realistic model atmospheres are thus essential for reliable reconstruction of the early chemical enrichment history of the Galaxy.2025A&A...703A.199Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/703/A199CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/703/A199https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/703/A199http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/703/A199https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/703/A199https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/703/A199http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/703/A199GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/703/A199/abund (Carbon abundances of selected targets from the SAGA database, 3D corrected using 3D RHD M3DIS models)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A199/abund?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A199/abund?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A199/abund?GETtext/xml+votable180.050000true240.99595197.05979220.0055555555555555566/31 51 122 146 200 215 232 241 253 324 706 783 798 800 822 872 874 911 934 1053 1107 1112 1125 1141 1147 1319-1320 1434-1435 1441 1463 1556 1642 1655 1828 1911 1937 1941 2133 2358 2405 2426 2463 2506 2515 2559 2638-2639 2650 2675 2691 2741 2798 2806 2900 2923 2988 3005 3020 3084 3094-3095 3099-3100 3112 3120 3240 3243 3267 3393 3435 3444 3520 3588 3654 3663 3687 3712 3751 3764 3828 3865 4018 4057 4091 4096 4184 4220 4376 4694 4783 4838-4839 4846 4854 4875 4901 4909 5012 5053 5082 5111 5154 5246 5339 5406 5531 5545 5580 5622 6058 6159 6238 6256 6308 6311 6313 6328 6348 6409 6453 6553 6627 6648 6747 6792 6890 6906 6925-6926 7016 7117 7143 7238 7565 7776 7794 7798 7851 7886 7931 7935 8064 8093 8111 8122 8205 8210 8215-8216 8258 8264 8296 8345 8381 8476 8737 8790 8814 8864 8930 8999 9026 9056 9072 9082 9125 9162 9298 9301 9403 9418 9438 9476 9496 9537 9582 9596 9679 9686 9831 9835 9912 9942 9957 9992 10165 10368 10382 10430 10820 10899 10936 10943 11072 11123 11250 11266 11290 11302-11303 11363 11442 11489 11612 11644 11773 11920 11971 12337 12397 12451 12503 12514 12555 12581 12590 12621 12645 12650 12694 12704 12716 12790 12793 12815 12890 13020 13081 13087 13264 13399 13474 13554 13556 13568 13570 13628 13698 13718 13829-13830 13943 14004 14021 14121 14146 14204 14290 14313 14353 14385 14588 14606 14726 14746 14793 14882 14931 14944 14948-14949 14961 14964 15108 15118 15152 15664 15815 15848 15962 16069 16115 16157 16216 16413 16415 16433 16456 16473 16496 16499 16501 16522 16549 16566 16587 16603 16609 16635 16641 16659 16666 16671 16678-16680 16759 16763 16777 16795 16814-16815 16828 16854 16880 16883 16911 16935 16988 17021 17035-17036 17056 17062 17136 17159-17160 17171 17174 17190-17191 17199 17218 17221 17229 17281 17327 17353 17370 17381 17392 17406 17425 17432 17460 17483 17492 17495 17512 17543 17545 17555 17564 17570 17576 17588 17598 17623 17625 17642 17664 17726 17730 17734 17773 17782 17788 17811 17879 17923 17936 17977 17986 17994 18002 18035 18041 18091 18108 18123 18135 18139 18292 18312 18342 18443 18483 18503 18507 18511 18514 18578 18582 18587 18606 18614 18637 18648 18653 18715 18718 18737 18764 18768 18778 18788 18810 18827 18839 18887 18903 18942 18953 18973 19017 19055 19083 19094 19185 19227 19304 19312 19317 19323 19347 19385 19478 19484 19566 19585 19602 19901 19903 19973 20171 20278 20402 20440 20446 20467 20474 20481 20541 20646 20661 20687 20720 20732 20756 20886 21126 21157 21188 21244 21254 21466 21665 21696 21715 21809 21866 22048 22090 22125 22180 22205 22263 22300 22432 22456 22518 22594 22625 22664 22685 22793 22829 22909 23008 23011 23013 23096 23107 23111 23143 23190 23199 23208 23217 23235 23240 23249 23435 23495 23734 23785 23873 23892 23978 24017 24019 24093 24096 24099 24151 24183 24197 24210 24212 24214 24217 24225 24290 24303 24583 24588 24592 24601 24674 24704 24752 24775 24827 24832 24905 24920 24924 24942 24951 24975 24991 24994-24995 25008 25030 25050 25131 25197-25198 25209 25279 25299 25326 25342 25357 25385 25431 25444 25469-25470 25486 25511 25527 25540 25554 25595 25656 25677 25702 25723 25755 25785-25787 25799 25811 25813 25819 25869-25870 25891 25926 25936 25938 25948 25956 25959 26003 26005 26019 26025 26030 26111 26152 26166 26176 26220 26232 26239 26241 26246 26261 26284 26289 26415 26455 26462 26530 26575 26577 26581 26594 26657-26658 26676 26829 26852 26888 26933 26941 26944 26958 26961 26994 27024 27030 27032 27035 27142 27145-27146 27162 27176 27182 27319 27330 27394 27444 27446 27589 27661 27693 27857 27946 27969 27975 28097 28148 28154 28265 28322 28336 28396 28421 28475 28594 28605 28664 28915 29004 29490 29515 29640 29661 29703 29777 29958 30051 30154 30179 30296 30528 30577 30648 30798 30875 30891 30907 30913 30939 30943 30963 30980 30989 31007 31048 31094 31100 31136 31220 31270 31366 31393 31395 31398 31418-31419 31427 31445 31447 31478 31503 31543 31546 31595 31625 31642 31650 31661 31697 31772 31785 31874 31999 32135 32335 32341 32467-32468 32593 32619 32645 32658 32684 32820 33198 33249 33260 33303 33348 33419 33471 33502 33515 33526-33527 33579 33585 33596 33599 33633 33635 33653 33696 33707-33708 33850 33861 33891 33989 34008-34009 34012 34019 34024 34029 34037 34046 34078 34095 34122 34183 34200 34210 34222 34246 34272 34274 34305 34326 34329 34334 34418 34425 34433-34434 34457 34461-34462 34498 34504 34507 34513 34546 34600 34606 34642 34684 34695 34708 34749 34751 34762 34826 34836 34844 34857 34862 34876 34912 34955 34995 35032 35072 35077 35093 35117 35166 35181 35186 35354 35395 35408 35453 35469 35521 35561 35588 35593 35599 35622 35649 35752 35772-35773 35775 35782 35784 35786 35803 35841 35891 35899 35913 35992 36035 36037 36084 36118 36168 36196 36228 36273 36280 36289 36295 36310 36375 36379 36426 36461 36503 36527 36540 36564-36565 36628 36650 36658 36670 36690 36722-36723 36734 36745 36799 36802 36806 36813 36837 36840 36915 36933 36965 36984 36988 37017 37059 37067 37107 37126 37133 37249 37266 37271 37314 37330 37339 37351 37390 37412 37424 37449 37487 37514 37584 37633 37673 37873 37882 37993 38036 38067 38072 38182 38216 38397 38430 38781 38792 38798 38868 38933 38955 39084 39103 39136 39138 39204-39206 39213 39224 39226 39312 39324 39446 39547 39762 39822 39847 39851 39861 40351 40410 40437 40506 40692 40716 40722 40758 40823 40900 40909 40944 40987 40992 41121 41245 41259-41260 41291 41310 41319 41460 41529 41608 41731 41850 41906 42008 42020 42059 42105-42106 42331 42502 42594 42705 42873 42895 42928 43070 43179 43235 43245 43295 43310 43445 43529 43575 43588 43786 43938 44016 44208 44219 44223 44268 44281 44331 44500 44541-44542 44571 44580 44607 44617 44625 44642 44658 44671 44735 44816 44842 44892 44910 44917 44939 45017 45021 45023 45159 45210 45226 45228 45309 45323 45342 45353 45374 45395 45397 45404 45441 45463 45468 45489 45491 45494 45507 45514 45546 45669 45716 45745 45753 45773 45804 45806 45818 45837-45838 45840 45873 45876 45913 45959 45969 45995 46008 46023 46053-46054 46067-46068 46090 46108 46283 46302 46365 46370 46409 46446 46490 46492-46493 46517 46526 46532 46540 46548 46554 46563 46565 46574-46575 46614 46642 46665 46668 46677 46679 46686-46687 46695 46699 46704 46755 46760 46791 46828 46840 46848 46879 46909 46931 47014 47018 47021-47022 47063 47139 47193 47217 47306 47334 47344 47347 47371 47389 47421 47458-47459 47472 47476 47478 47483 47512 47518-47519 47530 47540-47541 47558 47596 47610 47627 47794 47803 48129 48138 48153 48223 48240 48281 48387-48388 48392 48411 48484 48511 48514 48517 48526 48534 48555 48557 48603 48613-48614 48625 48628 48660 48719-48720 48722 48731 48734 48736 48766 48865 48870 48998 49009https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/703/A199?format=asciidefaultJ/A+A/703/A199/abundCarbon abundances of selected targets from the SAGA database, 3D corrected using 3D RHD M3DIS modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject IDmeta.id;meta.maincharRefsList of referencesmeta.ref;pos.framecharTeff[4000/7949] Effective temperatureKphys.temperature.effectiveintlogg[2.7/5.1] Log10 surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]Mettalicity, [Fe/H]phys.abund.Fefloat[C/Fe]1DAbundance [C/Fe] (1D)phys.abundfloat[C/Fe]3DAbundance [C/Fe] (3D corrected)phys.abundfloatSimbadNameSimbad column added by the CDSmeta.idcharnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable