J/A+A/713/A296ivo://CDS.VizieR/J/A+A/713/A296CDSMolaro P.Bonifacio P.Caffau E.Monaco L.Cescutti G.2026-09-24T07:38:47Z2026-09-24T08:38:21ZCDS support team

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

cds-question@unistra.frmilky-way-galaxychemical-abundancesvisible-astronomySurveys of Galactic halo stars have revealed numerous streams and substructures tracing stellar populations accreted by the Milky Way. Among these, Gaia-Sausage-Enceladus (GSE) and Sequoia are the most prominent, both associated with dwarf galaxies accreted about 10Gyr ago. We aim to measure beryllium abundances in nine stars associated with Thamnos, a substructure possibly linked to Sequoia, following the discovery of a Be-rich star BPM 3066 by Monaco et al. (2025A&A...697A..75M, Cat. J/A+A/697/A75). We used Gaia photometry and parallaxes to compute ATLAS9 model atmospheres. Synthetic spectra were generated with turbospectrum and used with MyGIsFOS in single-model mode to analyze UVES high resolution spectra. Four new stars exhibit a significant beryllium overabundance. Moreover, the two known Be-rich stars, HD 106038 and HD 132475, are also found consistent with Thamnos membership. Thus, all currently known Be-rich stars appear associated with the Thamnos-2 structure. The Be enhancement is accompanied by elevated Si abundances, and we detect a correlation between Be and neutron-capture elements. No comparable Be-rich population is known elsewhere in the Galaxy, pointing to a rare enrichment event. The measured A(Be)/A(Li) excess ratio bears the imprint of spallation reactions, pointing to a highly energetic event in which fast CNO nuclei fragmented upon collision with the surrounding medium. The silicon overabundance is also consistent with a hypernova origin. Such an event may have rapidly enriched the surrounding gas to [Fe/H]=~-1.5, explaining the relatively high metallicities of stars formed from this material despite their old ages (~13Gyr)2026A&A...713A.296Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/713/A296CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/713/A296https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/713/A296http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/713/A296https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/713/A296https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/713/A296http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/713/A296GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/713/A296/tables (Data for all the stars (tables 1, 2, 3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/713/A296/tables?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/713/A296/tables?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/713/A296/tables?GETtext/xml+votable180.050000true183.005703613.26128310.0055555555555555566/27857 29753 32893 33163 34683-34684 38810 40338 41080 43788 44281 47484https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/713/A296?format=asciiOpticaldefaultJ/A+A/713/A296/tablesData for all the stars (tables 1, 2, 3)SimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 identifiermeta.id;meta.mainTeffEffective temperatureKphys.temperature.effectiveintloggLogarithm of surface gravity c.g.s.log(cm.s**-2)phys.gravityfloatmicromicroturbulent velocitykm/sphys.velocfloatOH? log(O/H)+12 from OH linesphys.abundfloatnullables_OHsigma of OHstat.stdevdoubleo_OHof OH lines usedmeta.numberintNaI? log(Na/H)+12 from NaI linesphys.abundfloatnullables_NaIsigma of NaIstat.stdevdoubleo_NaIof NaI lines usedmeta.numberintMgIlog(Mg/H)+12 from MgI linesphys.abundfloats_MgIsigma of MgIstat.stdevfloato_MgIof MgI lines usedmeta.numberintSiI? log(Si/H)+12 from SiI linesphys.abundfloatnullables_SiIsigma of SiIstat.stdevdoubleo_SiIof SiII lines usedmeta.numberintSiII? log(Si/H)+12 from SiII linesphys.abundfloatnullables_SiIIsigma of SiIIstat.stdevdoubleo_SiIIof SiII lines usedmeta.numberintCaIlog(Ca/H)+12 from CaI linesphys.abundfloats_CaIsigma of CaIstat.stdevdoubleo_CaIof CaI lines usedmeta.numberintScI? log(Sc/H)+12 from ScI linesphys.abundfloatnullables_ScIsigma of ScIstat.stdevdoubleo_ScIof ScI lines usedmeta.numberintScIIlog(Sc/H)+12 from ScII linesphys.abundfloats_ScIIsigma of ScIIstat.stdevfloato_ScIIof ScII lines usedmeta.numberintTiIlog(Ti/H)+12 from TiI linesphys.abundfloats_TiIsigma of TiIstat.stdevfloato_TiIof TiI lines usedmeta.numberintTiIIlog(Ti/H)+12 from TiII linesphys.abundfloats_TiIIsigma of TiIIstat.stdevfloato_TiIIof TiII lines usedmeta.numberintVII? log(V/H)+12 from VII linesphys.abundfloatnullables_VIIsigma of VIIstat.stdevdoubleo_VIIof VII lines usedmeta.numberintCrIlog(Cr/H)+12 from CrI linesphys.abundfloats_CrIsigma of CrIstat.stdevfloato_CrIof CrI lines usedmeta.numberintCrIIlog(Cr/H)+12 from CrII linesphys.abundfloats_CrIIsigma of CrIIstat.stdevfloato_CrIIof CrII lines usedmeta.numberintMnI? log(Mn/H)+12 from MnI linesphys.abundfloatnullables_MnIsigma of MnIstat.stdevdoubleo_MnIof MnI lines usedmeta.numberintMnII? log(Mn/H)+12 from MnII linesphys.abundfloatnullables_MnIIsigma of MnIIstat.stdevdoubleo_MnIIof MnII lines usedmeta.numberintFeIlog(Fe/H)+12 from FeI linesphys.abund.Fefloats_FeIsigma of FeIstat.stdevfloato_FeIof FeI lines usedmeta.numberintFeIIlog(Fe/H)+12 from FeII linesphys.abund.Fefloats_FeIIsigma of FeIIstat.stdevfloato_FeIIof FeII lines usedmeta.numberintCoIlog(Co/H)+12 from CoI linesphys.abundfloats_CoIsigma of CoImeta.id.CoIfloato_CoIof CoI lines usedmeta.numberintNiIlog(Ni/H)+12 from NiI linesphys.abundfloats_NiIsigma of NiIstat.stdevfloato_NiIof NiI lines usedmeta.numberintNiII? log(Ni/H)+12 from NiII linesphys.abundfloatnullables_NiIIsigma of NiIIstat.stdevdoubleo_NiIIof NiII lines usedmeta.numberintCuI? log(Cu/H)+12 from CuI linesphys.abundfloatnullables_CuIsigma of CuIstat.stdevdoubleo_CuIof CuI lines usedmeta.numberintZnI? log(Zn/H)+12 from ZnI linesphys.abundfloatnullables_ZnIsigma of ZnIstat.stdevdoubleo_ZnIof ZnI lines usedmeta.numberintSrII? log(Sr/H)+12 from SrII linesphys.abundfloatnullables_SrIIsigma of SrIIstat.stdevdoubleo_SrIIof SrII lines usedmeta.numberintYI? log(Y/H)+12 from YI linesphys.abundfloatnullables_YIsigma of YIstat.stdevdoubleo_YIof YI lines usedmeta.numberintYIIlog(Y/H)+12 from YII linesphys.abundfloats_YIIsigma of YIIstat.stdevfloato_YIIof YII lines usedmeta.numberintZrII? log(Zr/H)+12 from ZrII linesphys.abundfloatnullables_ZrIIsigma of ZrIIstat.stdevdoubleo_ZrIIof ZrII lines usedmeta.numberintBaIIlog(Ba/H)+12 from BaII linesphys.abundfloats_BaIIsigma of BaIIstat.stdevfloato_BaIIof BaII lines usedmeta.numberintYbII? log(Yb/H)+12 from YbII linesphys.abundfloatnullables_YbIIsigma of YbIIstat.stdevdoubleo_YbIIof YbII lines usedmeta.numberintAgeAgeMyrtime.agedoublee_AgeError on ageMyrstat.error;time.agedoublelogMlog Masslog(solMass)phys.massdoublee_logMError on logMlog(solMass)stat.errordoubleABelog(Be/H)+12 from BeII resonance doubletphys.abunddoublee_ABeError on ABestat.errordoubleALilog(Li/H) from LiI resonance doublet in 1D LTEphys.abundfloatAli3DNLTElog(Li/H) from LiI resonance doublet in 3D NLTEphys.abunddoublee_ALiError on AListat.errordoubleEWLi? Equivalent width of the Li resonance doublet0.1nmspect.line.eqWidthfloatnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main