J/A+A/625/A59ivo://CDS.VizieR/J/A+A/625/A59doi:10.26093/cds/vizier.36250059CDSJustesen A.B.Albrecht S.2019-05-10T12:53:15Z2019-05-10T06:46:55ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityastrometryThe formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter {tau} Boo Ab orbits the primary star in the long-period (P>~1000yr), highly eccentric (e~0.9) double star system {tau} Bootis. Due to the long orbital period, the orbit of the stellar binary is poorly constrained. Here we aim to constrain the orbit of the stellar binary {tau} Boo AB in order to investigate the formation and migration history of the system. The mutual orbital inclination of the stellar companion and the hot Jupiter has important implications for planet migration. The binary eccentricity and periastron distance are important for understanding the conditions under which {tau} Boo formed. We combine more than 150 years of astrometric data with twenty-five years of high-precision radial velocities. The combination of sky-projected and line-of-sight measurements places tight constraints on the orbital inclination, eccentricity, and periastron distance of {tau} Boo AB. We determine the orbit of {tau} Boo B and find an orbital inclination of 47.2^+2.7^_-3.7_{deg}, a periastron distance of 28.3^+2.3^_-3.0_au, and an eccentricity of 0.87^+0.04^_-0.03_. We find that the orbital inclinations of {tau} Boo Ab and {tau} Boo B, as well as the stellar spin-axis of {tau} Boo A coincide at ~45 degrees, a result consistent with the assumption of a well-aligned, coplanar system. The likely aligned, coplanar configuration suggests planetary migration within a well-aligned protoplanetary disc. Due to the high eccentricity and small periastron distance of {tau} Boo B, the protoplanetary disc was tidally truncated at ~6au. We suggest that {tau} Boo Ab formed near the edge of the truncated disc and migrated inwards with high eccentricity due to spiral waves generated by the stellar companion.2019A&A...625A..59Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/A59CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/578/A64 : Velocity curve of {tau} Boo A (Borsa+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/A59https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/A59http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/A59https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/A59https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/A59http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/A59GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/625/A59/astrodatAstrometric measurements of tau BoorecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObs.dateDate of observation in decimal yearsyrtime.epochdoublerhoSky-projected separationarcsecpos.angDistancedoublee_rho? Formal uncertainty of rho (1)arcsecstat.errordoublenullablethetaPosition angledegpos.posAngdoublee_theta? Formal uncertainty of theta (1)degstat.error;pos.posAngdoublenullableJ/A+A/625/A59/rvdat1Radial velocities of tau Boo (Lick Dewar 6, 8, 13)RVRelative radial velocitym/sphys.veloc;pos.heliocentricdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian date of observationdtime.epochdoublee_RVFormal uncertainty on radial velocitym/sstat.errordoubleSetup[1/3] Setup used for observation (1)instr.setupintJ/A+A/625/A59/rvdat2Radial velocities of tau Boo (HARPS)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian date of observationdtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVFormal uncertainty on radial velocitym/sstat.errordoubleSetup[4] Setup used for observation (1)instr.setupint