J/ApJ/883/105ivo://CDS.VizieR/J/ApJ/883/105doi:10.26093/cds/vizier.18830105CDSTorres G.2021-05-03T09:00:00Z2021-03-24T10:12:36ZCDS support team

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

cds-question@unistra.frmultiple-starsThe empirical mass-luminosity relation in the Hyades cluster rests on dynamical mass determinations for five binary systems, of which one is eclipsing and the other four are visual or interferometric binaries. The last one was identified and first measured more than 20yr ago. Here we present dynamical mass measurements for a new binary system in the cluster, 80 Tau, which is also a visual pair with a much longer orbital period of about 170yr. Although we lack the radial-velocity information that has enabled the individual mass determinations in all of the previous binaries, we show that it is still possible to derive the component masses for 80 Tau using only astrometric observations. This is enabled by the accurate proper motion measurements from the Hipparcos and Gaia missions, which constrain the orbital acceleration in the plane of the sky. Separate proper motion values from Gaia for the primary and secondary provide a direct constraint on the mass ratio. Our mass measurements, M_A_=1.63_-0.13_^+0.30^M_{sun}_ and M_B_=1.11_-0.14_^+0.21^M_{sun}_, are consistent with the mass-luminosity relation defined by the five previously known systems, which in turn is in good agreement with current models of stellar evolution.2019ApJ...883..105Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/883/105CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2020)I/259 : The Tycho-2 Catalogue (Hog+ 2000)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/A+AS/101/551 : Optical polarization of 1000 stars (Leroy 1993)J/A+A/331/81 : Hyades membership (Perryman+ 1998)J/A+A/341/121 : Visual binary orbits and masses (Soederhjelm 1999)J/AJ/120/2638 : CCD speckle obs. of binary stars. II. (Horch+, 2000)J/A+A/381/446 : Astrometric Radial Velocities. III. (Madsen+, 2002)J/A+A/393/897 : Rotational velocities of A-type stars II. (Royer+, 2002)J/ApJS/159/100 : Temperatures and Rc photometry in the Hyades (Taylor+, 2005)J/AJ/131/3008 : Double star speckle measures (Horch+, 2006)J/ApJS/176/262 : VRI photometry & theta values in open clusters (Taylor+, 2008)J/A+A/493/1099 : CaII HK emission in rapidly rotating stars (Schroeder+, 2009)J/other/Ser/180.71 : Masses of visual binaries (Cvetkovic+, 2010)J/A+A/531/A92 : Deep all-sky census of the Hyades (Roeser+, 2011)J/A+A/546/A69 : Orbits of visual binaries and dynamical masses (Malkov+, 2012)J/A+A/559/A43 : Pan-STARRS1 (PS1) observations of the Hyades (Goldman+, 2013)J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)J/ApJ/795/161 : Activity & rotation in Praesepe & Hyades (Douglas+, 2014)J/ApJ/804/146 : Atmospheric parameters for nearby B-F stars (David+, 2015)J/ApJ/826/171 : IR data of debris disk vs metallicity of stars (Gaspar+, 2016)J/MNRAS/456/2070 : Eccentricity distribution of wide bin. (Tokovinin+, 2016)J/ApJ/856/23 : BANYAN. XI. The BANYAN {Sigma} algorithm (Gagne+, 2018)J/A+A/623/A72 : Binarity of HIP stars from Gaia pm anomaly (Kervella+, 2019)J/PAZh/45/35 : Orbits of 451 wide visual double stars (Izmailov, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/883/105https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/883/105http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/883/105https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/883/105https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/883/105http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/883/105GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/883/105/table1Visual observations of 80 TaurecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintYear[1831.18/2015.846] Year of observation in Julian yearsyrtime.epochdoublePA[1.7/78.2]? Position angle {theta} (1)degpos.posAngfloatnullablee_PA[0.012/0.15]? Position angle uncertainty along tangential direction {sigma}_t_ (2)arcsecstat.errorfloatnullable(O-C)t[-8.4/22.2]? Position angle (O-C)_{theta}_ valuedegpos.posAngfloatnullable(O-C)t/sig[-2.7/3.1]? Position angle (O-C)_{theta}_ value divided by uncertainty in theta {sigma}_{theta}_stat.error;pos.posAngfloatnullablerho[0.4/1.9]? Angular separation {rho}arcsecpos.angDistancefloatnullablee_rho[0.012/0.2]? Uncertainty in rho {sigma}_{rho}_ (2)arcsecstat.errorfloatnullable(O-C)rho[-0.4/0.4]? Angular separation (O-C)_{rho}_ valuearcsecpos.angDistancefloatnullable(O-C)rho/sig[-2.2/2.7]? Angular separation (O-C)_{rho}_ divided by uncertainty in rho {sigma}_{rho}_stat.error;pos.angDistancefloatnullable