J/ApJ/835/251ivo://CDS.VizieR/J/ApJ/835/251doi:10.26093/cds/vizier.18350251CDSWilson R.E.Pilachowski C.A.Terrell D.2017-10-26T13:12:47Z2017-09-22T13:05:10ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsradial-velocityinfrared-photometryvisible-astronomyphotometrySpectral features, radial velocities, elemental abundance estimates, other spectral data, and BVI_C_ light curves are reported for the double-M dwarf eclipsing binary CU Cancri-a good target for a radius check versus the Zero Age Main Sequence (ZAMS) due to the low component masses and corresponding very slow evolutionary expansion. The estimate of [Fe/H] is about 0.4, although continuum placement and other difficulties due to line crowding introduce the usual uncertainties for red dwarfs. Detection of the LiI{lambda}6707 line was attempted, with an estimated upper limit of 50m{AA}. Spectral and photometric indicators of stellar activity are described and illustrated. Other objectives were to measure the stellar radii via simultaneous velocity and light-curve solutions of earlier and new data while also improving the ephemeris by filling gaps in timewise coverage with the new velocities and eclipse data from the new light curves. The radii from our solutions agree within about 2% with those from Ribas, being slightly larger than expected for most estimates of the ZAMS. Some aspects of the red dwarf radius anomaly are briefly discussed. Evolution tracks show only very slight age-related expansion for masses near those in CU Cnc. Such expansion could be significant if CU Cnc were similar in age to the Galaxy, but then its Galactic velocity components should be representative of Population II, and they are not.2017ApJ...835..251Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/835/251CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)J/A+A/398/239 : RI differential photometry of CU Cnc (Ribas, 2003)J/ApJ/628/411 : Identification & analysis of eclipsing binaries (Devor+, 2005)J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)J/MNRAS/406/2559 : BVRI light curves of GSC2314-0530 (Dimitrov+, 2010)J/ApJ/709/535 : Masses and radii of eclipsing binaries (Brown, 2010)J/ApJ/723/1469 : Flux calibrations and WZ Oph photometry (Wilson+, 2010)J/AJ/141/78 : Low-mass eclipsing binaries in KIC (Coughlin+, 2011)J/MNRAS/431/3240 : Ji photometry of WTS 19g-4-02069 (Nefs+, 2013)J/A+A/572/A50 : J0113+31 light + velocity curves (Gomez Maqueo Chew+, 2014)J/ApJ/789/102 : Properties of late M-dwarfs (Janson+, 2014)J/MNRAS/442/2620 : VRI light curve of 5 eclipsing binaries (Zhang+, 2014)J/MNRAS/437/2831 : 4 transiting F-M binary systems (Zhou+, 2014)J/other/PASA/31.24 : Milky Way detached double-lined EB catalog (Eker+, 2014)J/AJ/149/131 : Param. of galactic nearby main-sequence stars (Eker+, 2015)J/AJ/152/180 : Bolometric fluxes of EB* in Tycho-2 (Stassun+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/835/251https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/835/251http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/835/251https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/835/251https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/835/251http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/835/251GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/ApJ/835/251/table1Radial velocity observations with the Phoenix SpectrometerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDMidpoint Heliocentric Julian date; HJD-2450000dtime.epochdoubleExp[600/900] Integration timestime.epochintRV1[-55/72] Radial velocity of the Primarykm/sspect.dopplerVelocfloatRV2[-71/68] Radial velocity of the Secondarykm/sspect.dopplerVelocfloatR[3/19] Tonry-Davis (1979AJ.....84.1511T) "R" value (1)stat.correlationfloatsig[0.5/1.4]? Standard deviation of the four independent measurementskm/sstat.stdevfloatnullableJ/ApJ/835/251/table3*Light curves in B, V , and I_C_ bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD-B? Heliocentric Julian Date of B band observationdtime.epochdoublenullabledelBmag[-0.6/0.4]? Differential B band magnitudemagphot.mag;arith.difffloatnullableHJD-VHeliocentric Julian Date of V band observationdtime.epochdoubledelVmag[-0.9/-0.4] Differential V band magnitudemagphot.mag;arith.difffloatHJD-Ic? Heliocentric Julian Date of I_c_ band observationdtime.epochdoublenullabledelIcmag[-2.8/-2.5]? Differential I_c_ band magnitudemagphot.mag;arith.difffloatnullable