J/A+A/372/477ivo://CDS.VizieR/J/A+A/372/477doi:10.26093/cds/vizier.33720477CDSMarco A.Bernabeu G.2017-11-10T11:15:56Z2005-03-31T21:42:56ZCDS support team

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

cds-question@unistra.fropen-star-clustersvisible-astronomymedium-band-photometryWe present uvby{beta} CCD photometry of the central region of the double cluster h&{chi} Persei. We identify =~350 stars, of which 214 were not included in Oosterhof's catalogue. Our magnitude limit V=16.5 allows us to reach early F spectral type and obtain very accurate fits to the ZAMS. We derive reddening values of E(b-y)=0.44+/-0.02 for h Persei and E(b-y)=0.39+/-0.05 for {chi} Persei. From the ZAMS fitting, we derive distance moduli V_0_-M_V_=11.66+/-0.20 and V_0_-M_V_=11.56+/-0.20 for h and {chi} Persei respectively. These values are perfectly compatible with both clusters being placed at the same distance and having identical reddenings. The shift in the main-sequence turnoff and isochrone fitting, however, show that there is a significant age difference between both clusters, with the bulk of stars in h Persei being older than {chi} Persei. There is, however, a significant population of stars in h Persei which are younger than {chi} Persei. All this argues for at least three different epochs of star formation, corresponding approximately to logt=7.0, 7.15 and 7.3.2001A&A...372..477Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/372/477CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/27 : Proper Motions and UBV Photometry in h+chi Per (Muminov 1980)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/372/477https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/372/477http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/372/477https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/372/477https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/372/477http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/372/477GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/372/477/table2a (*New stars in h Persei (not in Oosterhoff catalog))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/372/477/table2a?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/372/477/table2a?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/372/477/table2a?GETtext/xml+votable180.050000true34.8032363957.171433610.005555555555555556Cone search capability for table J/A+A/372/477/table8 (Stromgren photometry of member of h Per)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/372/477/table8?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/372/477/table8?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/372/477/table8?GETtext/xml+votable180.050000true34.68766757.1218640.005555555555555556Cone search capability for table J/A+A/372/477/table9 (Stromgren photometry of member of {chi} Per)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/372/477/table9?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/372/477/table9?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/372/477/table9?GETtext/xml+votable180.050000true35.42897957.0919170.005555555555555556Cone search capability for table J/A+A/372/477/table2b (*New stars in {chi} Persei, not in Oosterhoff catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/372/477/table2b?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/372/477/table2b?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/372/477/table2b?GETtext/xml+votable180.050000true35.4175580657.102823330.0055555555555555566/3256-3258https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/372/477?format=asciiOpticaldefaultJ/A+A/372/477/table2a*New stars in h Persei (not in Oosterhoff catalog)recnoRecord number assigned by the VizieR team. Should Not be used for identification.intNameName of the source (1)intFrame[1/2] 1 for h Persei and 2 for {chi} PerseiintXpixX Position in pixel (2)pixdoubleXposX Position in arcsecarcsecdoubleYpixY position in pixel (2)pixdoubleYposY position in arcsecarcsecfloat_RAPositions computed from (Xpos,Ypos) by VizieR (right ascension part)degpos.eq.ra;meta.main_DEPositions computed from (Xpos,Ypos) by VizieR (declination part)degpos.eq.dec;meta.mainJ/A+A/372/477/table8Stromgren photometry of member of h PerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.intNameName of the source (1)intprimaryn_Nameindicates that intrinsic photometry is available in tables 12charVmagV magnitudemagfloatb-yb-y colour indexmagfloatm1m1 colour indexmagfloatc1c1 colour indexmagfloatbeta? {beta} colour indexmagfloatnullablee_Vmag? Standard deviation in Vmagmagfloatnullablee_b-y? Standard deviation in b-ymagfloatnullablee_m1? Standard deviation in m1magfloatnullablee_c1? Standard deviation in c1magfloatnullablee_beta? Standard deviation in betamagfloatnullableo_uvbyNumber of measurements in each filterinto_betaNumber of measurement in betaint_RASimbad column added by the CDSdegpos.eq.ra;meta.main_DESimbad column added by the CDSdegpos.eq.dec;meta.mainJ/A+A/372/477/table9Stromgren photometry of member of {chi} PerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.intNameName of the source (1)intprimaryn_Nameindicates that intrinsic photometry is available in tables 12charVmagV magnitudemagfloatb-yb-y colour indexmagfloatm1m1 colour indexmagfloatc1c1 colour indexmagfloatbeta? {beta} colour indexmagfloatnullablee_Vmag? Standard deviation in Vmagmagfloatnullablee_b-y? Standard deviation in b-ymagfloatnullablee_m1? Standard deviation in m1magfloatnullablee_c1? Standard deviation in c1magfloatnullablee_beta? Standard deviation in betamagfloatnullableo_uvbyNumber of measurements in each filterinto_betaNumber of measurement in betaint_RASimbad column added by the CDSdegpos.eq.ra;meta.main_DESimbad column added by the CDSdegpos.eq.dec;meta.mainJ/A+A/372/477/table14aIntrinsic photometry of member of h PerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.intNameName of the sourceintV0magV_0_ magnitudemagfloat(b-y)0(b-y)_0_ colour indexmagfloatc0c_0_ indexmagfloatSpTypeSpectral Type (1)charJ/A+A/372/477/table14bIntrinsic photometry of member of {chi} PerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.intNameName of the sourceintV0magV_0_ magnitudemagfloat(b-y)0(b-y)_0_ colour indexmagfloatc0c_0_ indexmagfloatSpTypeSpectral Type (1)charJ/A+A/372/477/table2b*New stars in {chi} Persei, not in Oosterhoff catalogNameName of the source (1)intrecnoRecord number assigned by the VizieR team. Should Not be used for identification.intFrame[1/2] 1 for h Persei and 2 for {chi} PerseiintXpixX Position in pixel (2)pixdoubleXposX Position in arcsecarcsecdoubleYpixY position in pixel (2)pixdoubleYposY position in arcsecarcsecfloat_RAPositions computed from (Xpos,Ypos) by VizieR (right ascension part)degpos.eq.ra;meta.main_DEPositions computed from (Xpos,Ypos) by VizieR (declination part)degpos.eq.dec;meta.main