J/other/NatAs/2.ivo://CDS.VizieR/J/other/NatAs/2.393doi:10.26093/cds/vizier/dt/ckdjdCDSSanterne A.Brugger B.Armstrong D.J.Adibekyan V.Lillo-Box J.,Gosselin H.Aguichine A.Almenara J.-M.Barrodo D.Barros S.C.C.,Bayliss D.Boisse I.Bonomo A.S.Bouchy F.Brown D.J.A.Deleuil M.,Delgado Mena E.Demangeon O.Diaz R.F.Doyle A.Dumusque X.Faedi F.,Faria J.P.Figueira P.Foxell E.Giles H.Hebrard G.Hojjatpanah S.,Hobson M.Jackman J.King G.Kirk J.Lam K.W.F.Ligi R.Lovis C.,Louden T.Mccormac J.Mousis O.Neal J.J.Osborn H.P.Pepe F.,Pollacco D.Santos N.C.Sousa S.G.Udry S.Vigan A.2026-03-04T20:02:55Z2023-10-03T14:20:35ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityvisible-astronomyEarth, Venus, Mars and some extrasolar terrestrial planets1 have a mass and radius that is consistent with a mass fraction of about 30% metallic core and 70% silicate mantle. At the inner frontier of the Solar System, Mercury has a completely different composition, with a mass fraction of about 70% metallic core and 30% silicate mantle. Several formation or evolution scenarios are proposed to explain this metal-rich composition, such as a giant impact, mantle evaporation or the depletion of silicate at the inner edge of the protoplanetary disk. These scenarios are still strongly debated. Here, we report the discovery of a multiple transiting planetary system (K2-229) in which the inner planet has a radius of 1.165+/-0.066 Earth radii and a mass of 2.59+/-0.43 Earth masses. This Earth-sized planet thus has a core-mass fraction that is compatible with that of Mercury, although it was expected to be similar to that of Earth based on host-star chemistry. This larger Mercury analogue either formed with a very peculiar composition or has evolved, for example, by losing part of its mantle. Further characterization of Mercury-like exoplanets such as K2-229 b will help to put the detailed in situ observations of Mercury (with MESSENGER and BepiColombo) into the global context of the formation and evolution of solar and extrasolar terrestrial planets.2018NatAs...2..393Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/NatAs/2.393CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/NatAs/2.393https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/NatAs/2.393http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/NatAs/2.393https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/NatAs/2.393https://vizier.iucaa.in/viz-bin/votable?-source=J/other/NatAs/2.393http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/NatAs/2.393GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/other/NatAs/2.393/table3Radial velocity datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTime (BJD-2400000)dtime.epochdoubleRVRadial velocitykm/sphys.veloc;pos.heliocentricdoublee_RVrms uncertainty on RVm/sstat.errorfloatFWHMFWHMkm/sspect.line.widthfloate_FWHMrms uncertainty on FWHMm/sstat.error;phys.angSizefloatBISBissector spanm/sphys.velocfloate_BISrms uncertainty on BISm/sstat.errorfloatTexpExposure timestime.duration;obs.exposureintS/NSignal-to-noise ratiostat.snrfloatJ/other/NatAs/2.393/table4Spectroscopic indicesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTime (BJD-2400000)dtime.epochdoubleSMWMont Wilson S indexphot.flux;arith.ratiofloate_SMWrms uncertainty on SMWstat.errorfloatIHaH{alpha} indexspect.index;em.line.Halphafloate_IHarms uncertainty on IHastat.errorfloatINaDSodium I D indexspect.indexfloate_INaDrms uncertainty on INaDstat.errorfloatIHeID3Helium I D3 line indexspect.indexfloate_IHeID3rms uncertainty on IHeID3stat.errorfloat