J/A+A/557/A119ivo://CDS.VizieR/J/A+A/557/A119doi:10.26093/cds/vizier.35570119CDSSouthworth J.2017-07-03T14:25:53Z2013-09-18T08:37:00ZCDS support team

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

cds-question@unistra.freclipsing-binary-starssolar-system-planetsphotometryThe eclipsing binary LL Aqr consists of two late-type stars in an eccentric orbit with a period of 20.17d. We use an extensive light curve from the SuperWASP survey augmented by published radial velocities and UBV light curves to measure the physical properties of the system. The primary star has a mass of 1.167+/-0.009M_{sun}_ and a radius of 1.305+/-0.007R_{sun}_. The secondary star is an analogue of the Sun, with a mass and radius of 1.014+/-0.006M_{sun}_ and 0.990+/-0.008R_{sun}_ respectively. The system shows no signs of stellar activity: the upper limit on spot-induced rotational modulation is 3mmag, it is slowly rotating, has not been detected at X-ray wavelengths, and the calcium H and K lines exhibit no emission. Theoretical stellar models provide a good match to its properties for a sub-solar metal abundance of Z=0.008 and an age of 2.5Gyr. Most low-mass eclipsing binary systems are found to have radii larger than expected from theoretical predictions, blamed on tidally-enhanced magnetic fields in these short- period systems. The properties of LL Aqr support this scenario: it exhibits negligible tidal effects, shows no signs of magnetic activity, and matches theoretical models well.2013A&A...557A.119Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/557/A119CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/557/A119https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/557/A119http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/557/A119https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/557/A119https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/557/A119http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/557/A119GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/557/A119/spectrumEchelle spectrumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOrder[1/89] Echelle order of the flux measurementstat.variance;phot.fluxintlambda[3830/9586] Wavelength of flux measurement0.1nmphot.fluxdoubleFluxExtracted spectrum flux at this wavelengthctphot.fluxfloatJ/A+A/557/A119/wasplcSuperWASP light curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCamera[141/223] Internal identification number of camera usedmeta.numberintHJDTime of midpoint of observation in HJD(UTC)dtime.epochdoubledmagDifferential g+r band magnitude of LL Aqrmagphot.mag;arith.diffdoublee_dmagMeasurement error of dmagmagstat.error;phot.magfloat