J/A+A/683/A111ivo://CDS.VizieR/J/A+A/683/A111doi:10.26093/cds/vizier.36830111CDSGrisoni V.Chiappini C.Miglio A.Brogaard K.Casali G.Willett E.,Montalban J.Stokholm A.Thomsen J.S.Tailo M.Matteuzzi M.,Valentini M.Elsworth Y.Mosser B.2024-11-29T20:00:59Z2024-03-12T09:45:22ZCDS support team

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

cds-question@unistra.frmilky-way-galaxylate-type-starsvisible-astronomyThe origin of apparently young {alpha}-rich stars in the Galaxy is still a matter of debate in Galactic archaeology, whether they are genuinely young or might be products of binary evolution, and mergers or mass accretion. Our aim is to shed light on the nature of young {alpha}-rich stars in the Milky Way by studying their distribution in the Galaxy thanks to an unprecedented sample of giant stars that cover different Galactic regions and have precise asteroseismic ages, and chemical and kinematic measurements. We analyzed a new sample of ~6000 stars with precise ages coming from asteroseismology. Our sample combines the global asteroseismic parameters measured from light curves obtained by the K2 mission with stellar parameters and chemical abundances obtained from APOGEE DR17 and GALAH DR3, then cross-matched with Gaia DR3. We define our sample of young {alpha}-rich stars and study their chemical, kinematic, and age properties. We investigated young {alpha}-rich stars in different parts of the Galaxy and we find that the fraction of young {alpha}-rich stars remains constant with respect to the number of high-{alpha} stars at ~10%. Furthermore, young {alpha}-rich stars have kinematic and chemical properties similar to high-{alpha} stars, except for [C/N] ratios. Thanks to our new K2 sample, we conclude that young {alpha}-rich stars have similar occurrence rates in different parts of the Galaxy, and that they share properties similar to the normal high-{alpha} population, except for [C/N] ratios. This suggests that these stars are not genuinely young, but are products of binary evolution, and mergers or mass accretion. Under that assumption, we find the fraction of these stars in the field to be similar to that found recently in clusters. This suggests that ~10% of the low-{alpha} field stars could also have their ages underestimated by asteroseismology. This should be kept in mind when using asteroseismic ages to interpret results in Galactic archaeology.2024A&A...683A.111Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/683/A111CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/683/A111https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/683/A111http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/683/A111https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/683/A111https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/683/A111http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/683/A111GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/683/A111/tablea1 (List of IDs for the best-candidate young alpha-rich stars present in both samples studied in our paper)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/683/A111/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/683/A111/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/683/A111/tablea1?GETtext/xml+votable180.050000true204.704575-17.52308110.0055555555555555565/12007 6/281 284 337 368 1064 4263 4269 4300 4306 4313 4318-4319 4523 4637 4866 4901 17290 17292 17354 18011 18015 18128 18131 18135 18308 18450 18459 18465 18490 18551 18571 18591 18610 18615 18627 18630 18642 18662 18664 18700 18709 18742 18884 19537 25610 25619 25628 25644 25646 25650 25662-25663 25673 25676 25678 25729 25732 26124 26259 26941 27089 27099 27125 27392 27418 27462 27469 27509 27525 27687 27784 28943 28954 28981 29024 29195 29317 42869 42941 42978 42984 42997 44362 44376-44377 44719 44770 48023 48607https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/683/A111?format=asciiOpticaldefaultJ/A+A/683/A111/tablea1List of IDs for the best-candidate young alpha-rich stars present in both samples studied in our paperrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName, K2 ID with the corresponding campaign (KTWONNNNNNNNN-CNNN)meta.id;meta.mainchar_RAPositions from K2 (Cat. IV/34) (right ascension part)degpos.eq.ra;meta.main_DEPositions from K2 (Cat. IV/34) (declination part)degpos.eq.dec;meta.main