J/A+A/642/A225ivo://CDS.VizieR/J/A+A/642/A225doi:10.26093/cds/vizier.36420225CDSAmazo-Gomez E.M.Shapiro A.I.Solanki S.K.Kopp G.Oshagh M.,Reinhold T.Reiners A.2021-04-27T13:18:22Z2020-10-23T10:37:34ZCDS support team

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

cds-question@unistra.frvariable-starsphotometryStellar rotation periods can be determined by observing brightness variations caused by active magnetic regions transiting visible stellar disk as the star rotates. The successful stellar photometric surveys stemming from the Kepler and TESS observations led to the determination of rotation periods in tens of thousands of young and active stars. However, there is still a lack of information about rotation periods of older and less active stars, like the Sun. The irregular temporal profiles of light curves caused by the decay times of active regions, which are comparable to or even shorter than stellar rotation periods, combine with the random emergence of active regions to make period determination for such stars very difficult. We tested the performance of the new method for the determination of stellar rotation periods against stars with previously determined rotation periods. The method is based on calculating the gradient of the power spectrum (GPS) and identifying the position of the inflection point (i.e. point with the highest gradient). The GPS method is specifically aimed at determining rotation periods of low-activity stars like the Sun. We applied the GPS method to Sun-like stars observed by the Kepler telescope. We separately considered two stellar samples: one with near-solar rotation periods (24-27.4d) and broad range of effective temperatures (5000-6000K), another with near-solar effective temperatures (5700-5900K) and broad range of rotation periods (15-40d). We show that the GPS method returns precise values of stellar rotation periods. Furthermore, it allows us to constrain the ratio between facular and spot areas of active regions at the moment of their emergence. We show that relative facular area decreases with stellar rotation rate. Our results suggest that the GPS method can be successfully applied to retrieve periods of stars with both regular and non-regular light curves.2020A&A...642A.225Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/642/A225CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/133 : Kepler Input Catalog (Kepler Mission Team, 2009)J/ApJS/211/2 : Q1-16 Kepler targets revised stellar properties (Huber+, 2014)J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)J/A+A/583/A65 : Active Kepler stars differential rotation (Reinhold+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/642/A225https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/642/A225http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/642/A225https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/642/A225https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/642/A225http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/642/A225GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/642/A225/table2 (Faculae-Spot dominance & rotation periods (GPS outcome values))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/A225/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/A225/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/A225/table2?GETtext/xml+votable180.050000true287.950098346.92370640.0055555555555555564/922 935 945-946 5/3645-3647 3692-3694 3704 3706 3730 3732-3734 3736 3738-3739 3776 3778-3779 3788-3789 3792 6/14567 14577-14579 14730-14731 14733-14735 14744 14746 14750-14751 14781-14783 14792 14794 14822 14828 14830 14914-14915 14917-14919 14924 14926 14940-14942 14948-14950 15040-15041 15043-15044 15056-15057 15060-15062 15109-15111 15160 15172-15174 15178 15200 15232https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/642/A225?format=asciidefaultJ/A+A/642/A225/table2Faculae-Spot dominance & rotation periods (GPS outcome values)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintKICID star Designationmeta.id;meta.mainintPHFIPHigh Frequency Inflection Point period (1) (2)dtime.period;em.freqdoublee_PHFIPHigh Frequency Inflection Point period 2-sigma uncertaintydstat.errordoublealphaalpha factor (1)stat.fit.paramdoublee_alphaalpha factor 2-sigma uncertaintystat.error;pos.eq.radoubleProtGPSRotation period by GPS (3)dtime.periodfloatProtGLS? Rotation period by GLS (4)dtime.periodfloatnullableProtACFRotation period by ACF (5)dtime.periodfloatVarVariability amplitude within 1 period (5)(10-6)src.var.amplitudedoubleloggSurface gravity (6)log(cm.s**-2)phys.gravitydouble[Fe/H]Metallicity (6)phys.abund.ZfloatTeffEffective temperature (6)Kphys.temperature.effectiveintSimbadSimbad column added by the CDSmeta.ref.urlchar_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