J/ApJ/726/52ivo://CDS.VizieR/J/ApJ/726/52doi:10.26093/cds/vizier.17260052CDSHartman J.D.Bakos G.A.Sato B.Torres G.Noyes R.W.Latham D.W.,Kovacs G.Fischer D.A.Howard A.W.Johnson J.A.Marcy G.W.,Buchhave L.A.Furesz G.Perumpilly G.Beky B.Stefanik R.P.,Sasselov D.D.Esquerdo G.A.Everett M.Csubry Z.Lazar J.Papp I.,Sari P.2017-06-01T08:52:25Z2012-09-11T06:56:05ZCDS support team

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

cds-question@unistra.frvisible-astronomysloan-photometryradial-velocitysolar-system-planetsk-starsmultiple-starsWe report the discovery of two new transiting extrasolar planets. HAT-P-18b orbits the V=12.759 K2 dwarf star GSC 2594-00646, with a period P=5.508023+/-0.000006 days, transit epoch T_c_=2454715.02174+/-0.00020(BJD), and transit duration 0.1131+/-0.0009 days. The host star has a mass of 0.77+/-0.03M_{sun}_, radius of 0.75+/-0.04R_{sun}_, effective temperature 4803+/-80K, and metallicity [Fe/H]=+0.10+/-0.08. The planetary companion has a mass of 0.197+/-0.013M_J_ and radius of 0.995+/-0.052R_J_, yielding a mean density of 0.25+/-0.04g/cm^3^. HAT-P-19b orbits the V=12.901 K1 dwarf star GSC 2283-00589, with a period P=4.008778+/-0.000006 days, transit epoch T_c_=2455091.53417+/-0.00034(BJD), and transit duration 0.1182+/-0.0014 days. The host star has a mass of 0.84+/-0.04M_{sun}_, radius of 0.82+/-0.05R_{sun}_, effective temperature 4990+/-130K, and metallicity [Fe/H]=+0.23+/-0.08. The planetary companion has a mass of 0.292+/-0.018M_J_ and radius of 1.132+/-0.072R_J_, yielding a mean density of 0.25+/-0.04g/cm^3^. The radial velocity residuals for HAT-P-19 exhibit a linear trend in time, which indicates the presence of a third body in the system. Comparing these observations with theoretical models, we find that HAT-P-18b and HAT-P-19b are each consistent with a hydrogen-helium-dominated gas giant planet with negligible core mass. HAT-P-18b and HAT-P-19b join HAT-P-12b and WASP-21b in an emerging group of low-density Saturn-mass planets, with negligible inferred core masses. However, unlike HAT-P-12b and WASP-21b, both HAT-P-18b and HAT-P-19b orbit stars with super-solar metallicity.2011ApJ...726...52Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/726/52CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/422/2024 : Exoplanet evaporation (Jackson+, 2012)J/MNRAS/411/L46 : Exoplanet magnetic fields (Vidotto+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/726/52https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/726/52http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/726/52https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/726/52https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/726/52http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/726/52GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/726/52/table4Relative radial velocities, bisector spans, and activity index measurements of HAT-P-18recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (BJD-2454000) (1)dtime.epochdoublef_BJD[e] e: outlier RV measurements excluded from the analysismeta.codecharRV? Relative radial velocity (2)m/sphys.veloc;arith.difffloatnullablee_RV? RV uncertainty (3)m/sstat.errorfloatnullableBSBisector spanm/sphys.velocfloate_BSBS uncertaintym/sstat.errorfloatSActivity index (4)spect.indexfloate_SS uncertaintystat.errorfloatInstInstrument (Subaru or Keck)meta.id;instrcharJ/ApJ/726/52/table5Relative radial velocities, bisector spans, and activity index measurements of HAT-P-19SActivity index (4)spect.indexfloate_SS uncertaintystat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (BJD-2454000) (1)dtime.epochdoublef_BJD[e] e: outlier RV measurements excluded from the analysismeta.codecharRV? Relative radial velocity (2)m/sphys.veloc;arith.difffloatnullablee_RV? RV uncertainty (3)m/sstat.errorfloatnullableBSBisector spanm/sphys.velocfloate_BSBS uncertaintym/sstat.errorfloatInstInstrument (Subaru or Keck)meta.id;instrcharJ/ApJ/726/52/table6High-precision differential photometry of HAT-P-18recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBaryocentric Julian Date (BJD-2400000)dtime.epochdoublemagProcessed magnitude in Filter (1)magphot.magdoublee_magThe 1{sigma} error in magmagstat.error;phot.magdoubleRmagRaw magnitude in Filter (2)magphot.magdoubleFilt[gi] KeplerCam filter used in the observation (only i for HAT-P-19)instr.setup;obscharJ/ApJ/726/52/table7High-precision differential photometry of HAT-P-19recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBaryocentric Julian Date (BJD-2400000)dtime.epochdoublemagProcessed magnitude in Filter (1)magphot.mag;em.opt.Idoublee_magThe 1{sigma} error in magmagstat.error;phot.magdoubleRmagRaw magnitude in Filter (2)magphot.mag;em.opt.IdoubleFilt[gi] KeplerCam filter used in the observation (only i for HAT-P-19)instr.setup;obschar