J/ApJ/845/72ivo://CDS.VizieR/J/ApJ/845/72doi:10.26093/cds/vizier.18450072CDSKraus A.L.Douglas S.T.Mann A.W.Agueros M.A.Law N.M.Covey K.R.,Feiden G.A.Rizzuto A.C.Howard A.W.Isaacson H.Gaidos E.Torres G.,Bakos G.2026-05-29T20:04:55Z2018-04-06T15:29:20ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsinfrared-photometryvisible-astronomyphotometryradial-velocityTheoretical models of stars constitute the fundamental bedrock upon which much of astrophysics is built, but large swaths of model parameter space remain uncalibrated by observations. The best calibrators are eclipsing binaries in clusters, allowing measurement of masses, radii, luminosities, and temperatures for stars of known metallicity and age. We present the discovery and detailed characterization of PTFEB132.707+19.810, a P=6.0day eclipsing binary in the Praesepe cluster ({tau}~600-800Myr; [Fe/H]=0.14+/-0.04). The system contains two late-type stars (SpT_P_=M3.5+/-0.2; SpT_S_=M4.3+/-0.7) with precise masses (M_p_=0.3953+/-0.0020M_{sun}_; M_s_=0.2098+/-0.0014M_{sun}_) and radii (R_p_=0.363+/-0.008R_{sun}_; R_s_=0.272+/-0.012R_{sun}_). Neither star meets the predictions of stellar evolutionary models. The primary has the expected radius but is cooler and less luminous, while the secondary has the expected luminosity but is cooler and substantially larger (by 20%). The system is not tidally locked or circularized. Exploiting a fortuitous 4:5 commensurability between Porb and P_rot,prim_, we demonstrate that fitting errors from the unknown spot configuration only change the inferred radii by <~1%-2%. We also analyze subsets of data to test the robustness of radius measurements; the radius sum is more robust to systematic errors and preferable for model comparisons. We also test plausible changes in limb darkening and find corresponding uncertainties of ~1%. Finally, we validate our pipeline using extant data for GU Boo, finding that our independent results match previous radii to within the mutual uncertainties (2%-3%). We therefore suggest that the substantial discrepancies are astrophysical; since they are larger than those for old field stars, they may be tied to the intermediate age of PTFEB132.707+19.810.2017ApJ...845...72Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/845/72CatalogResearchIsServedByTAP VizieR generic servicerelated-toIII/116 : Spectrophotometric Standards (Massey+ 1988)VI/39 : Model Atmospheres (Kurucz, 1979)V/139 : SDSS Photometric Catalog, DR9 (Adelman-McCarthy+, 2012)J/AJ/124/1570 : JHKs photometry in Praesepe (Adams+, 2002)J/ApJ/640/1018 : Differential photometry of V1061 Cyg (Torres+, 2006)J/AJ/134/2340 : Membership of Praesepe & Coma Berenices (Kraus+, 2007)J/MNRAS/389/585 : Fundamental parameters of M dwarfs (Casagrande+, 2008)J/AJ/136/2158 : CV Boo V-band and radial velocity curves (Torres+, 2008)J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)J/A+A/502/253 : V636 Cen radial velocities curves (Clausen+, 2009)J/ApJ/691/1400 : Absolute properties of CM Dra (Morales+, 2009)J/A+A/510/A21 : Stellar Limb-Darkening Coefficients (Sing, 2010)J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)J/MNRAS/413/2218 : Stellar rotation in Hyades and Praesepe (Delorme+, 2011)J/ApJ/742/123 : Photometry and Velocity of LSPM J1112+7626 (Irwin+, 2011)J/ApJ/728/48 : Multicolor eclipse data for 6 new binaries (Kraus+, 2011)J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)J/MNRAS/426/3419 : UKIDSS GCS Praesepe members (Boudreault+, 2012)J/ApJ/757/112 : Stellar diameters. II. K and M-stars (Boyajian+, 2012)J/A+A/546/A14 : Limb-darkening for CoRoT, Kepler, Spitzer (Claret+, 2012)J/AJ/143/4 : Kepler cycle 1 obs. of low-mass stars (Harrison+, 2012)J/ApJ/779/188 : Spectra of nearby late K and M Kepler stars (Mann+, 2013)J/ApJ/770/43 : Spectroscopic [Fe/H] of Kepler stars (Mann+, 2013)J/ApJ/775/L11 : Stellar rotation periods for KOIs (McQuillan+, 2013)J/A+A/556/A15 : Effective temp. scale of M dwarfs (Rajpurohit+, 2013)J/ApJ/788/L9 : Stellar param. of KIC planet-host stars (Bastien+, 2014)J/AJ/147/82 : Monitoring of disk-bearing stars in NGC2264 (Cody+, 2014)J/ApJ/795/161 : Activity & rotation in Praesepe & Hyades (Douglas+, 2014)J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)J/ApJ/804/64 : Empirical and model param. of 183 M dwarfs (Mann+, 2015)J/AJ/152/141 : Solar neighborhood. XXXVII. (Benedict+, 2016)J/ApJ/822/47 : K2 rotation periods for Hyades members (Douglas+, 2016)J/ApJS/224/2 : K2 EPIC properties for 138600 targets (Huber+, 2016)J/ApJ/821/93 : M dwarfs rotation & Galactic kinematics (Newton+, 2016)J/ApJ/836/124 : 2yrs of eclipse data & RVs for LP661-13 (Dittmann+, 2017)J/A+A/600/A55 : Refined Analysis of T-Cyg1-12664 (Iglesias-Marzoa+, 2017)J/ApJ/842/83 : Praesepe members periods from K2 LCs (Douglas+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/845/72https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/845/72http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/845/72https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/845/72https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/845/72http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/845/72GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/845/72/table1PTF PhotometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpochEpoch, HJD-2450000dtime.epochdoublePhasePhasetime.phasefloatRmag[16.6/17.5] PTF aperture R magnitudemagphot.mag;em.opt.Rfloate_Rmag[0.006/0.07] Uncertainty in Rmagmagstat.error;phot.mag;em.opt.RfloatJ/ApJ/845/72/table2K2 PhotometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpochEpoch, HJD-2450000dtime.epochdoublePhasePhasetime.phasefloatFlux[0.7/1.2] K2 aperture photometry, normalizedphot.flux;arith.ratiofloate_Flux[0.001/0.07] Uncertainty in Flux, normalizedstat.error;phot.fluxfloatJ/ApJ/845/72/table4Keck-I/HIRES radial velocities (RVs)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTarget Namemeta.id;meta.maincharf_Name[TS] (T)arget (PTFEB132.707+19.810); (S)tandard starmeta.codecharDate? UT fractional date, Keck Archive observationyrtime.epoch;obsdoublenullableEpochEpoch of observation, HJD-2450000dtime.epochdoublelambda-min[3360/4450] Wavelength range, min0.1nminstr.bandwidthintlambda-max[8100/8910] Wavelength range, max0.1nminstr.bandwidthintTinit[120/1200] Exposure time, secondsstime.duration;obs.exposureintHRV1[0.2/68.1]? Heliocentric radial velocity, primary (1)km/sspect.dopplerVeloc;pos.heliocentricfloatnullablee_HRV1[0.07/1.6]? Uncertainty in HRV1km/sstat.errorfloatnullablesigma1[7.6/9]? Broadening function, primary (2)km/sstat.stdevfloatnullablee_sigma1[0.06/0.9]? Uncertainty in sigma1km/sstat.errorfloatnullableHRV2[-32/99]? Heliocentric radial velocity, secondary (1)km/sspect.dopplerVeloc;pos.heliocentricfloatnullablee_HRV2[0.1/1.2]? Uncertainty in HRV2km/sstat.errorfloatnullablesigma2[6.7/9]? Broadening function, secondary (2)km/sstat.stdevfloatnullablee_sigma2[0.1/0.9]? Uncertainty in sigma2km/sstat.errorfloatnullableF1/F2[0.2/0.4]? Flux ratio, secondary/primaryphot.flux;arith.ratiofloatnullablee_F1/F2[0.01/0.05]? Uncertainty in F1/F2stat.error;phys.abundfloatnullable