J/MNRAS/435/3058ivo://CDS.VizieR/J/MNRAS/435/3058doi:10.26093/cds/vizier.74353058CDSDe Marchi G.Panagia N.Guarcello M.G.Bonito R.2024-08-06T20:17:09Z2014-11-12T11:42:42ZCDS support team

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

cds-question@unistra.fropen-star-clustersinfrared-photometryvisible-astronomybroad-band-photometryAttention is given to a population of 110 stars in the NGC 6611 cluster of the Eagle nebula that have prominent near-infrared excess and optical colours typical of pre-main-sequence (PMS) stars older than 8Myr. At least half of those for which spectroscopy exists have a H{alpha} emission line profile revealing active accretion. In principle, the V-I colours of all these stars would be consistent with those of young PMS objects (<1Myr) whose radiation is heavily obscured by a circumstellar disc seen at high inclination and in small part scattered towards the observer by the back side of the disc. However, using theoretical models it is shown here that objects of this type can only account for a few percent of this population. In fact, the spatial distribution of these objects, their X-ray luminosities, their optical brightness, their positions in the colour-magnitude diagram and the weak Li absorption lines of the stars studied spectroscopically suggest that most of them are at least eight times older than the ~1Myr-old PMS stars already known in this cluster and could be as old as ~30Myr. This is the largest homogeneous sample to date of Galactic PMS stars considerably older than 8Myr that are still actively accreting from a circumstellar disc and it allows us to set a lower limit of 7 percent to the disc frequency at ~16Myr in NGC 6611. These values imply a characteristic exponential lifetime of ~6Myr for disc dissipation.2013MNRAS.435.3058Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/435/3058CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+AS/121/223 : Multiphotometry of NGC6611 (de Winter+ 1997)J/A+AS/134/525 : NGC6611 compiled catalog (Belikov+ 1999)J/A+AS/144/195 : UBVRI polarimetric observations in NGC6611 (Orsatti+, 2000)J/A+A/462/245 : BVI photometry in NGC 6611 (Guarcello+, 2007)J/A+A/496/453 : Photometry of candidate members of NGC6611 (Guarcello+ 2009)J/AJ/132/1783 : UBVRI polarimetry of 25 stars in NGC6611 (Orsatti+, 2006)J/MNRAS/392/1034 : IZJHKL' photometry of NGC6611 (Oliveira+, 2009)J/MNRAS/400/1479 : RV catalogue of O-type stars in NGC6611 (Sana+, 2009)J/A+A/521/A18 : Blue stars with disk photometry in NGC6611 (Guarcello+ 2010)J/A+A/521/A61 : Stars associated to Eagle Nebula (NGC6611) (Guarcello+ 2010)J/ApJ/753/117 : X-ray catalog of Eagle Nebula (Guarcello+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/435/3058https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/435/3058http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/435/3058https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/435/3058https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/435/3058http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/435/3058GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/435/3058/table1 (Photometric catalogue of stars with NIR excess in NGC 6611)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/435/3058/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/435/3058/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/435/3058/table1?GETtext/xml+votable180.050000true274.87713611-13.758076110.0055555555555555566/29461 29463 29504 295062.367228618189496e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/435/3058?format=asciiOpticalInfrareddefaultJ/MNRAS/435/3058/table1Photometric catalogue of stars with NIR excess in NGC 6611recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/624] Stellar ID in NGC6611 (M16)meta.id;meta.mainintRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainVmagV magnitude (1)magphot.mag;em.opt.Vfloate_VmagV magnitude errormagstat.error;phot.mag;em.opt.VfloatIcmagIc magnitude (1)magphot.mag;em.opt.Ifloate_IcmagIc magnitude errormagstat.error;phot.mag;em.opt.IfloatX[O/Y/N] X-ray detection flag: Y=yes, N=no, N=not covered by X-ray observationsmeta.codecharFullOriginal observations previously published: Guarcello et al. 2007 (J/A+A/462/245); 2009 (J/A+A/496/453); 2010 (J/A+A/521/A61)meta.ref.urlchar