J/A+A/653/A41ivo://CDS.VizieR/J/A+A/653/A41doi:10.26093/cds/vizier.36530041CDSDemangeon O.D.S.Zapatero Osorio M.R.Alibert Y.Barros S.C.C.,Adibekyan V.H.M.TaberneroAntoniadis-Karnavas A.Camacho J.D.,Suarez Mascareno A.Oshagh M.Micela G.Sousa S.G.Lovis C.Pepe F.A.,Rebolo R.Cristiani S.Santos N.C.Allart R.AllendePrieto C.,Bossini D.Bouchy F.Cabral A.Damasso M.Di Marcantonio P.,D'Odorico V.D.EhrenreichFaria J.Figueira P.Genova Santos R.,Haldemann J.Hara N.Gonzalez Hernandez J.I.Lavie B.Lillo-Box J.,Lo Curto G.Martins C.J.A.P.Megevand D.Mehner A.Molaro P.,Nunes N.J.Palle E.Pasquini L.Poretti E.Sozzetti A.Udry S.2022-07-20T07:33:11Z2021-09-06T08:46:23ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityIn recent years, the advent of a new generation of radial velocity instruments has allowed us to detect lower and lower mass planets, breaking the one Earth-mass barrier. Here we report a new milestone in this context, by announcing the detection of the lightest planet measured so far using radial velocities: L 98-59 b, a rocky planet with half the mass of Venus which is part of a system composed of three known transiting terrestrial planets (planets b to d). We announce the discovery of a fourth non-transiting planet with a minimum mass of 3.06_-0.37_^+0.33^M_{Earth)_ and an orbital period of 12.796_-0.019_^+0.020^ days and report hints for the presence of a fifth non-transiting terrestrial planet. If confirmed, with a minimum mass of 2.46_-0.82_^+0.66^M_{Earth}_ and an orbital period 23.15_-0.17_^+0.60^ days, this planet would sit in the middle of the habitable zone of the L 98-59 system. L 98-59 is a bright M-dwarf located 10.6pc away. Positioned at the border of the continuous viewing zone of the James Webb space telescope, this system is destined to become a corner stone for comparative exoplanetology of terrestrial planets. The three transiting planets have transmission spectrum metrics ranging from 49 to 255 which undoubtedly make them prime targets for atmospheric characterization with the James Webb space telescope, the Hubble space telescope, Ariel or ground-based facilities like NIRPS or ESPRESSO. With equilibrium temperature ranging from 416 to 627K, they offer a unique opportunity to study the diversity of warm terrestrial planets without the unknowns associated with different host stars. L 98-59 b and c have densities of 3.6_-1.5_^+1.4^ and 4.57_-0.85_^+0.77^g/cm^3^ respectively and have very similar bulk compositions with a small iron core, representing only 12 to 14% of the total mass, and a small amount of water. However, with a density of 2.95_-0.51_^+0.79^g/cm^3^ and despite a similar core mass fraction, up to 30% of L 98-59 d's mass could be made of water.2021A&A...653A..41Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/653/A41CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/629/A111 : L 98-59 (TOI 175) HARPS observationshttps://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html : TESS datahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/653/A41https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/653/A41http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/653/A41https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/653/A41https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/653/A41http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/653/A41GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/653/A41/espressoRadial velocities and activity indicators measurement on L 98-59 with the ESPRESSO spectrographRVRadial velocitym/sphys.veloc;pos.heliocentricdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTime of the measurement, UTC (BJD-2400000)dtime.epochdoublee_RVUncertainty on the radial velocity (1 sigma)m/sstat.errordoubleFWHMFull width at half maximum of the cross-correlation functionm/sstat.correlationdoublee_FWHMUncertainty on the full width at half maximum (1 sigma)m/sstat.error;phys.angSizedoubleBISBisector span of the cross-correlation functionm/sphys.velocdoublee_BISUncertainty on the bisector span (1 sigma)m/sstat.errordoubleContrastContrast of the cross-correlation functionstat.fit.paramdoublee_ContrastUncertainty on the contrast (1 sigma)stat.errordoubleSindexMont-Wilson S indexspect.indexdoublee_SindexUncertainty on the S index (1 sigma)stat.errordoubleHalphaDepth of the Halpha linephys.absorption.opticalDepth;spect.linedoublee_HalphaUncertainty on the depth of the Halpha line (1 sigma)stat.error;spect.linedoubleNaDDepth of the sodium doublet linesphot.flux.density;arith.ratiodoublee_NaDUncertainty on the depth of the sodium doublet lines (1 sigma)stat.errordoubleBERVBarycentric Earth Radial Velocitym/sphys.veloc;arith.diffdoubleInstString indicating if the measurement has been acquired before (Pre) or after (Post) the June 2019 replacement of the fiber-link of ESPRESSOmeta.codechar