J/A+A/623/A159ivo://CDS.VizieR/J/A+A/623/A159doi:10.26093/cds/vizier.36230159CDSPrisinzano L.Damiani F.Kalari V.Jeffries R.Bonito R.Micela G.,Wright N.J.Jackson R.J.Tognelli E.Guarcello M.G.Vink J.S.,Klutsch A.Jimenez-Esteban F.M.Roccatagliata V.Tautvaisiene G.,Gilmore G.Randich S.Alfaro E.J.Flaccomio E.Koposov S.Lanzafame A.,Pancino E.Bergemann M.Carraro G.Franciosini E.Frasca A.Gonneau A.,Hourihane A.Jofre P.Lewis J.Magrini L.Monaco L.Morbidelli L.,Sacco G.G.Worley C.C.Zaggia S.2019-03-27T06:25:04Z2019-03-26T07:33:03ZCDS support team

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

cds-question@unistra.frglobular-star-clustersstellar-agespre-main-sequence-starsspectroscopyinfrared-photometryvisible-astronomyphotometryIn very young clusters, stellar age distribution is the empirical proof of the duration of star formation (SF) and of the physical mechanisms involved in the process. We derived accurate stellar ages for the cluster NGC6530, associated with the Lagoon Nebula to infer its SF history. We use the Gaia-ESO survey observations and Gaia DR2 data, to derive cluster membership and fundamental stellar parameters. We identified 652 confirmed and 9 probable members. The reddening inferred for members and non-members allows us to distinguish MS stars and giants, in agreement with the distances inferred from Gaia DR2 data. The foreground and background stars show a spatial pattern that traces the 3D structure of the nebular dust component. We derive stellar ages for 382 confirmed cluster members and we find that the gravity-sensitive gamma index distribution for M stars is correlated with stellar age. For all members with Teff<5500K, the mean logarithmic age is 5.84 (units of years) with a dispersion of 0.36dex. The age distribution of stars with accretion and/or disk (CTTSe) is similar to that of stars without accretion and without disk (WTTSp). We interpret this dispersion as evidence of a real age spread since the total uncertainties on age determinations, derived from Monte Carlo simulations, are significantly smaller than the observed spread. This conclusion is supported by the evidence of a decreasing of the gravity-sensitive gamma index as a function of stellar ages. The presence of the age spread is also supported by the spatial distribution and the kinematics of old and young members. In particular, members with accretion and/or disk, formed in the last 1Myr, show evidence of subclustering around the cluster center, in the Hourglass Nebula and in the M8-E region, suggesting a possible triggering of star formation events by the O-type star ionization fronts.2019A&A...623A.159Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/623/A159CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)J/A+A/430/941 : Star formation region NGC 6530 (Prisinzano+, 2005)J/MNRAS/440/2036 : VPHAS+ survey synthetic colours (Drew+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/623/A159https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/623/A159http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/623/A159https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/623/A159https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/623/A159http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/623/A159GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/623/A159/tablea1 (Literature data and Gaia-ESO survey parameters of cluster members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/623/A159/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/623/A159/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/623/A159/tablea1?GETtext/xml+votable180.050000true270.634-24.234670.0055555555555555566/28890-28891https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/623/A159?format=asciiOpticalInfrareddefaultJ/A+A/623/A159/tablea1Literature data and Gaia-ESO survey parameters of cluster membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCNameTarget Name in the Gaia-ESO archive, HHMMSSss+DDMMSSsmeta.id;meta.maincharVPHAS+VPHAS+ Target Name, HHMMSSss+DDMMSSsmeta.idcharRAJ2000Right Ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainVmag? Apparent V magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag? Error apparent V magnitudemagstat.error;phot.mag;em.opt.VfloatnullableImag? Apparent I magnitudemagphot.mag;em.opt.Ifloatnullablee_Imag? Error apparent I magnitudemagstat.error;phot.mag;em.opt.IfloatnullableHRV? Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatnullablee_HRV? rms uncertainty on HRVkm/sstat.errorfloatnullablevsini? Projected rotational velocitykm/sphys.veloc.rotatfloatnullablee_vsini? rms uncertainty on vsinikm/sstat.error;phys.veloc.rotatfloatnullableEWLi? 670.8nm Li equivalent width0.1pmspect.line.eqWidth;em.opt.Rfloatnullablee_EWLi? rms uncertainty on EWLi0.1pmstat.errorfloatnullableFWZI? Full width zero intensity0.1nmspect.line.widthfloatnullablee_FWZI? rms uncertainty of FWZI0.1nmstat.errorfloatnullablefXrays[0/1]? X-ray membership flag (1)meta.codeintnullableJ/A+A/623/A159/tablea2Gaia-ESO survey and Gaia parameters, individual reddenings and isochronal ages of membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCNameTarget Name in the Gaia-ESO archivemeta.id;meta.mainchargamma? Gravity index gammaspect.indexfloatnullablee_gamma? rms uncertainty of gammastat.errorfloatnullableTeff? effective temperatureKphys.temperature.effectivedoublenullablee_Teff? Standard error of TeffKstat.error;phys.temperature.effectivefloatnullablepmRA*? Gaia DR2 Proper motion in RA, pmRA*cosDEmas/yrpos.pm;pos.eq.rafloatnullablee_pmRA*? Gaia DR2 Stand. error of pmRA*mas/yrstat.error;pos.pm;pos.eq.rafloatnullablepmDE? Gaia DR2 Proper Motion in DEmas/yrpos.pm;pos.eq.decfloatnullablee_pmDE? Gaia DR2 Stand. error of pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatnullablePlx? Gaia DR2 parallaxmaspos.parallaxfloatnullablee_Plx? Gaia DR2 Standard error of plxmasstat.error;pos.parallaxfloatnullableE(V-I)? Color excess E(V-I)magphot.color.excessfloatnullablee_E(V-I)? Standard error of E(V-I)magstat.errorfloatnullablet? Logarithmic stellar agelog(yr)time.agefloatnullablee_t? Uncertainty of tlog(yr)stat.errorfloatnullablefMem[M PM] Membership flag (2)meta.code.membercharftype[CTTSe WTTSp] Member type (3)meta.codechar