J/A+A/629/A111ivo://CDS.VizieR/J/A+A/629/A111doi:10.26093/cds/vizier.36290111CDSCloutier R.Astudillo-Defru N.Bonfils X.Jenkins J.S.Berdinas Z.,Ricker G.Vanderspek R.Latham D.W.Seager S.Winn J.Jenkins J.M.,Almenara J.M.Bouchy F.Delfosse X.Diaz M.R.Diaz R.F.Doyon R.,Figueira P.Forveille T.Kurtovic N.T.Lovis C.Mayor M.Menou K.,Morgan E.Morris R.Muirhead P.Murgas F.Pepe F.Santos N.C.,Segransan D.Smith J.C.Tenenbaum P.Torres G.Udry S.Vezie M.,Vilasenor J.2019-09-13T08:14:57Z2019-09-13T09:07:47ZCDS support team

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

cds-question@unistra.frm-starsmultiple-starsexoplanetsradial-velocityL 98-59 (TIC 307210830, TOI-175) is a nearby M3 dwarf around which TESS revealed three small transiting planets (0.80, 1.35, 1.57 Earth radii) in a compact configuration with orbital periods shorter than 7.5 days. Here we aim to measure the masses of the known transiting planets in this system using precise radial velocity (RV) measurements taken with the HARPS spectrograph. We considered both trained and untrained Gaussian process regression models of stellar activity, which are modeled simultaneously with the planetary signals. Our RV analysis was then supplemented with dynamical simulations to provide strong constraints on the planets' orbital eccentricities by requiring long-term stability. We measure the planet masses of the two outermost planets to be 2.42+/-0.35 and 2.31+/-0.46 Earth masses, which confirms the bulk terrestrial composition of the former and eludes to a significant radius fraction in an extended gaseous envelope for the latter. We are able to place an upper limit on the mass of the smallest, innermost planet of <1.01 Earth masses with 95% confidence. Our RV plus dynamical stability analysis places strong constraints on the orbital eccentricities and reveals that each planet's orbit likely has e<0.1. L 98-59 is likely a compact system of two rocky planets plus a third outer planet with a lower bulk density possibly indicative of the planet having retained a modest atmosphere. The system offers a unique laboratory for studies of planet formation, dynamical stability, and comparative atmospheric planetology as the two outer planets are attractive targets for atmospheric characterization through transmission spectroscopy. Continued RV monitoring will help refine the characterization of the innermost planet and potentially reveal additional planets in the system at wider separations.2019A&A...629A.111Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/629/A111CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/629/A111https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/629/A111http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/629/A111https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/629/A111https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/629/A111http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/629/A111GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/629/A111/harpsHARPS time-seriese_HbetaH-beta index uncertaintystat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTimestamp (BJD-2457000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricfloate_RVRadial velocity uncertaintym/sstat.errorfloatHalphaH-alpha index multiplied by 100spect.index;em.line.Halphafloate_HalphaH-alpha index uncertaintystat.errorfloatHbetaH-beta index multiplied by 100spect.index;em.line.HbetafloatHgammaH-gamma index multiplied by 100spect.index;em.line.Hgammafloate_HgammaH-gamma index uncertaintystat.errorfloatNaDSodium doublet indexmeta.code;spect.indexfloate_NaDSodium doublet index uncertaintystat.errorfloatSindexS-indexspect.indexfloate_SindexS-index uncertaintystat.errorfloatFWHM? Full width at half maximum of the cross-correlation functionstat.correlationfloatnullableBIS? Bisector of the cross-correlation functionphys.velocfloatnullableJ/A+A/629/A111/t175sampMCMC posterior sampleslnGammaGP coherencestat.fit.paramdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlnaGP covariance amplitudem/sstat.covariance;src.var.amplitudedoublelnlambdaGP expontential timescaledtime.scaledoublelnPGPGP periodic timescaledtime.scaledoublesRV jitterm/sphys.velocdoublegamma0Systemic velocitym/sphys.velocdoublePbL 98-59b orbital perioddtime.perioddoubleT0bL 98-59b mid-transit time ((BJD-2457000)dtime.epochdoubleKbL 98-59b semi-amplitudem/sphys.veloc;src.orbitaldoublehbL 98-59b h = sqrt(ecc)*cos(omega)src.orbital.eccentricitydoublekbL 98-59b k = sqrt(ecc)*sin(omega)src.orbital.eccentricitydoublePcL 98-59c orbital perioddtime.perioddoubleT0cL 98-59c mid-transit time (BJD-2457000)dtime.epochdoubleKcL 98-59c semi-amplitudem/sphys.veloc;src.orbitaldoublehcL 98-59c h = sqrt(ecc)*cos(omega)src.orbital.eccentricitydoublekcL 98-59c k = sqrt(ecc)*sin(omega)src.orbital.eccentricitydoublePdL 98-59d orbital perioddtime.perioddoubleT0dL 98-59d mid-transit time (BJD-2457000)dtime.epochdoubleKdL 98-59d semi-amplitudem/sphys.veloc;src.orbitaldoublehdL 98-59d h = sqrt(ecc)*cos(omega)src.orbital.eccentricitydoublekdL 98-59d k = sqrt(ecc)*sin(omega)src.orbital.eccentricitydouble