J/MNRAS/480/3739ivo://CDS.VizieR/J/MNRAS/480/3739doi:10.26093/cds/vizier.74803739CDSBastian N.Kamann S.Cabrera-Ziri I.Georgy C.Ekstrom S.,Charbonnel C.de Juan Ovelar M.Usher C.2024-08-18T20:21:19Z2022-06-20T12:49:42ZCDS support team

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

cds-question@unistra.fropen-star-clustersgalaxy-clustersvisible-astronomyWe present an analysis of the relatively low mass (~2400M_{sun}_), ~800Myr, Galactic open cluster, NGC 2818, using Gaia DR2 results combined with VLT/FLAMES spectroscopy. Using Gaia DR2 proper motions and parallax measurements, we are able to select a clean sample of cluster members. This cluster displays a clear extended main sequence turn-off (eMSTO), a phenomenon previously studied mainly in young and intermediate age massive clusters in the Magellanic clouds. The main sequence of NGC 2818 is extremely narrow, with a width of ~0.01 magnitudes (GBP-GRP), suggesting very low levels of differential extinction. Using VLT/FLAMES spectroscopy of 60 cluster members to measure the rotational velocity of the stars (Vsini), we find that stars on the red side of the eMSTO have high Vsini(>160km/s) while stars on the blue side have low Vsini(<160km/s), in agreement with model predictions. The cluster also follows the previously discovered trend between the age of the cluster and the extent of the eMSTO. We conclude that stellar rotation is the likely cause of the eMSTO phenomenon.2018MNRAS.480.3739Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/480/3739CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/480/3739https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/480/3739http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/480/3739https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/480/3739https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/480/3739http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/480/3739GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/480/3739/table1 (Properties of the selected cluster candidate using the position, Plx and proper motions)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/480/3739/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/480/3739/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/480/3739/table1?GETtext/xml+votable180.050000true139.012145996-36.6272468570.005555555555555556Cone search capability for table J/MNRAS/480/3739/table2 (Properties of the stars with Vsini measurements)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/480/3739/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/480/3739/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/480/3739/table2?GETtext/xml+votable180.050000true139.044769287-36.6507263180.0055555555555555566/399561.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/480/3739?format=asciiOpticaldefaultJ/MNRAS/480/3739/table1Properties of the selected cluster candidate using the position, Plx and proper motionsSimbadNameSimbad column added by the CDSmeta.idcharnullableBPmagGaia Integrated BP mean magnitudemagphot.mag;em.opt.BfloatpmRAProper motion in Right Ascension (pmRA*cosDE)mas/yrpos.pm;pos.eq.rafloate_pmRAError on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainplxParallaxmaspos.parallax.trigfloate_plxError on plxmasstat.error;pos.parallaxfloatpmDEProper motion in Declinationmas/yrpos.pm;pos.eq.decfloate_pmDEErron on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloate_BPmagError on BPmagmagstat.error;phot.magfloatRPmagGaia Integrated RP mean magnitudemagphot.mag;em.opt.Rfloate_RPmagError on RPmagmagstat.error;phot.magfloatJ/MNRAS/480/3739/table2Properties of the stars with Vsini measurementse_vsiniad? Error on vsiniadkm/sstat.errorfloatnullableRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainBPmagGaia BP magnitude (1)magphot.mag;em.opt.BfloatRPmagGaia RP magnitude (1)magphot.mag;em.opt.Rfloatvsini09? Rotational velocity from the HR09 grating (2)km/sphys.veloc.rotatfloatnullablee_vsini09? Error on vsini09km/sstat.errorfloatnullablevsini05? Rotational velocity from the HR05 grating (2)km/sphys.veloc.rotatfloatnullablee_vsini05? Error on vsini05km/sstat.errorfloatnullablevsiniad? Rotational velocity adopted valuekm/sphys.veloc.rotatfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 Idmeta.id;meta.main