J/A+A/674/A152ivo://CDS.VizieR/J/A+A/674/A152doi:10.26093/cds/vizier.36740152CDSFritzewski D.J.Barnes S.A.Weingrill J.Granzer T.Cole-Kodikara E.,Strassmeier K.G.2025-08-26T20:00:55Z2023-06-16T14:05:47ZCDS support team

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

cds-question@unistra.fropen-star-clusterslate-type-starsvariable-starsphotometryvisible-astronomyCool star rotation periods have become an important tool in determining ages of open clusters. We aim to estimate the age of the open cluster NGC 2281 based on the rotational properties of its low-mass members. Previous age estimates for this open cluster range from 275Myr to 630Myr. Based on an eight month-long photometric time series obtained at the 1.2 m robotic STELLA telescope in Tenerife, we measured rotation periods for 126 cool star members (70% of the observed members) of NGC 2281. The large set of rotation periods allows us to construct a rich colour-period diagram for NGC 2281 with very few outliers above the slow rotator sequence. We identify an evolved fast rotator sequence which can be used to accurately age date the open cluster relative to other open clusters. Comparisons with M37 and M48 show that all three open clusters are roughly coeval, and we estimate the age of NGC 2281 to be 435Myr. Through comparisons with the younger NGC 3532 and the older Praesepe, we determine the spin down rates of mid-K and early-M fast rotators to be significantly lower than for early-K stars. We suspect that the spin down of early-K fast rotators might be governed by an additional mass dependence. Finally, we show the path towards an empirical description of the evolved fast rotator sequences in open clusters.2023A&A...674A.152Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/674/A152CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/AJ/158/122 : Local structure & star formation history of the MWhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/674/A152https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/674/A152http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/674/A152https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/674/A152https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/674/A152http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/674/A152GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/674/A152/members (Membership for NGC 2281 (table 1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/674/A152/members?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/674/A152/members?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/674/A152/members?GETtext/xml+votable180.050000true102.1728140.729730.005555555555555556Cone search capability for table J/A+A/674/A152/periods (Rotation periods for members of NGC 2281 (table 2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/674/A152/periods?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/674/A152/periods?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/674/A152/periods?GETtext/xml+votable180.050000true101.7070140.730590.0055555555555555566/6717 6719 6760 67621.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/674/A152?format=asciiOpticaldefaultJ/A+A/674/A152/membersMembership for NGC 2281 (table 1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID? ID number for STELLA photometry (1)meta.idintnullableprimaryGaiaDR3Gaia DR3 designation (Cat. I/355)meta.id;meta.mainRA_ICRSRight ascension from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.ra;meta.mainDE_ICRSDeclination from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.dec;meta.mainGmagG-band mean magnitude from Gaia DR3 (Cat. I/355)magphot.mag;em.optfloat(G-RP)0? Dereddened Gaia Gmag-RPmag based on Gaia DR3 (Cat. I/355) (2)magphot.color;em.opt;em.optfloatnullableKC19[ny] Member in Kounkel et al., 2019AJ....158..122K, Cat. J/AJ/158/122meta.code.membercharRvar? Variability amplitude in STELLA photometry measured from V 120s light curvesmagsrc.var.amplitudefloatnullablePerindicates rotation period in periods.datmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/674/A152/periodsRotation periods for members of NGC 2281 (table 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDID number for STELLA photometrymeta.idintGaiaDR3Gaia DR3 designation (Cat. I/355)meta.id;meta.mainRA_ICRSRight ascension from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.ra;meta.mainDE_ICRSDeclination from Gaia DR3 (ICRS) at Ep=2016.0 (Cat. I/355)degpos.eq.dec;meta.main(G-RP)0Dereddened Gaia Gmag-RPmag based on Gaia DR3 (Cat. I/355) (1)magphot.color;em.opt;em.optfloatPerPhotometric rotation perioddtime.periodfloate_PerUncertainty on rotation perioddstat.errorfloatRo? Rossby number P_rot_/tau_c_ with tau_c_ based on Barnes & Kim (2010ApJ...721..675B)stat.paramfloatnullable