J/A+A/591/A43ivo://CDS.VizieR/J/A+A/591/A43doi:10.26093/cds/vizier.35910043CDSDistefano E.Lanzafame. A.C.Lanza A.F.Messina S.Spada F.2017-10-09T13:34:12Z2016-06-09T07:16:04ZCDS support team

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

cds-question@unistra.frlate-type-starsstellar-associationsstellar-distanceeffective-temperaturestellar-massesSurface differential rotation (SDR) plays a key role in dynamo models and determines a lower limit on the accuracy of stellar rotation period measurements. SDR estimates are therefore essential to constrain theoretical models and infer realistic rotation period uncertainties. We measure a lower limit to SDR in a sample of solar-like stars belonging to young loose stellar associations with the aim of investigating how SDR depends on global stellar parameters in the age range (4-95Myr). The rotation period of a solar-like star can be recovered by analyzing the flux modulation caused by dark spots and stellar rotation. The SDR and the latitude migration of dark-spots induce a modulation of the detected rotation period. We employed long-term photometry to measure the amplitude of such a modulation and to compute the quantity {Delta}{Omega}_phot_=2{pi}/P_min_-2{pi}/P_max_ that is a lower limit to SDR. We find that {Delta}{Omega}_phot_ increases with the stellar effective temperature and with the global convective turn-over timescale tau_c_, which is the characteristic time for the rise of a convective element through the stellar convection zone. We find that {Delta}{Omega}_phot_ is proportional to T_eff_^2.18+/-0.65^ in stars recently settled on the ZAMS. This power law is less steep than those found by previous authors, but closest to recent theoretical models. We investigate how {Delta}{Omega}_phot_ changes in time in a 1M_{sun}_ star. We find that {Delta}{Omega}_phot_ steeply increases between 4 and 30Myr and that it is almost constant between 30 and 95Myr. We find also that the relative shear increases with the Rossby number Ro. Although our results are qualitatively in agreement with hydrodynamical mean-field models, our measurements are systematically higher than the values predicted by these models. The discrepancy between {Delta}{Omega}_phot_ measurements and theoretical models is particularly large in stars with periods between 0.7 and 2d. Such a discrepancy, together with the anomalous SDR measured by other authors for HD 171488 (rotating in 1.31d), suggests that the rotation period could influence SDR more than predicted by the models.2016A&A...591A..43Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/591/A43CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/138/312 : Activity of bright solar analogs (Hall+, 2009)J/A+A/552/A78 : Solar like stars radial velocities (Zechmeister+, 2013)J/A+A/572/A34 : Pulsating solar-like stars in Kepler (Garcia+, 2014)J/A+A/520/A15 : RACE-OC project: YSOs within 100pc (Messina+, 2010)J/A+A/532/A10 : RACE-OC project. II. (Messina+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/591/A43https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/591/A43http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/591/A43https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/591/A43https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/591/A43http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/591/A43GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/591/A43/sample (Sample parameters (Tables 2-4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/591/A43/sample?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/591/A43/sample?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/591/A43/sample?GETtext/xml+votable180.050000true3.4708867-74.68828890.0055555555555555566/129 940 16426 17288 19888 20492 20510 20610 20618 20636 20650 21050 21135 22964 23094 24608 24763 25113 28746 28784 32836 32937 33050 33116 33312 33439 33583 33707 33850 34008 34012 34050 34102 34163 34165 34206 34385 34423 34436 34450 34586 34829-34830 35123 35861 35929 36487 36578 36713 37006 37012-37013 37065 37078 37125 37172-37173 37272 37414 37419 37494 37652 37664 37695 37781 37783 37785 37787 37811 37838 38061 38341 38363 38555 38742 38800 38936 38985 39123 39450 39489 39524 39579 39625 39735 39829 41128 41130 41139 41295 41481 41484 41505 41528 41600-41601 41798 43704 45072 45544 45927 46383 46922 47120 47287 47366 48061 48274 48905https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/591/A43?format=asciidefaultJ/A+A/591/A43/table5Stellar parameters inferred by the comparison of J and H magnitudes with different theoretical modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDASAS or SuperWasp ID (G1)meta.idcharMSiessMass from Siess et al. (2000A&A...358..593S) models (1)solMassphys.massfloatTeffSiessEffective temperature from Siess et al. (2000A&A...358..593S) models (1)Kphys.temperature.effectivefloatMBar? Mass from Baraffe et al. (1998, Cat. J/A+A/337/403) models (1)solMassphys.massfloatnullableTeffBar? Effective temperature from Baraffe et al. (1998, Cat. J/A+A/337/403) models (1)Kphys.temperature.effectivefloatnullableMSpada? Mass from Spada et al. (2013ApJ...776...87S) models (1)solMassphys.massfloatnullableTeffSpada? Effective Temperature from Spada et al. (2013ApJ...776...87S) models (1)Kphys.temperature.effectivefloatnullabletauC? Turnover convective time-scale from Spada et al. (2013ApJ...776...87S) models (1)dtime.epochfloatnullableRo? Rossby number (2)stat.paramfloatnullableJ/A+A/591/A43/sampleSample parameters (Tables 2-4)SimbadNameSimbad column added by the CDSmeta.idcharRef[1/6] Reference (3)meta.ref;pos.frameintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDASAS or SuperwaspID (G1)meta.idcharNameOther designationmeta.id;meta.maincharAssocAssociationmeta.id.parentcharB-VB-V colour index (2)magphot.color;em.opt.B;em.opt.VfloatSpTypeMK spectral type (2)src.spTypechar<P>Average rotation perioddtime.period;stat.meanfloatominLowest angular frequencyrad/dem.freqfloate_ominError on lowest angular frequencyrad/dstat.errorfloatomaxHighest angular frequencyrad/dem.freqfloate_omaxError on highest angular frequencyrad/dstat.errorfloatDOp{Delta}{Omega}_phot_ = omax-ominrad/dem.freq;arith.difffloate_DOpError on DeltaOmega_photrad/dstat.errorfloatalphap{alpha}_phot_ = (omax-omin)/omaxem.freq;arith.ratiofloate_alphapErrror on alpha_photstat.errorfloatNpNumber of time-series pointsmeta.numberintfQ[ABC] Quality flag (1)meta.code.qualcharfTTime-series flag (2)meta.codecharPlx? Parallaxmaspos.parallaxfloatnullableDistDistancepcpos.distancefloatDMDistance modulusmagphot.mag.distModfloatJMAG? Absolute J magnitude (1)magphys.magAbs;em.IR.JfloatnullableHMAG? Absolute H magnitude (2)magphys.magAbs;em.IR.Hfloatnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main