J/A+A/675/A52ivo://CDS.VizieR/J/A+A/675/A52doi:10.26093/cds/vizier.36750052CDSCastro-Gonzalez A.Demangeon O.D.S.Lillo-Box J.Lovis C.Lavie B.,Adibekyan V.Acuna L.Deleuil M.Aguichine A.Zapatero Osorio M.R.,Tabernero H.M.Davoult J.Alibert Y.Santos N.Sousa S.G.,Antoniadis-Karnavas A.Borsa F.Winn J.N.Allende Prieto C.Figueira P.,Jenkins J.M.Sozzetti A.Damasso M.Silva A.M.Astudillo-Defru N.,Barros S.C.C.Bonfils X.Cristiani S.Di Marcantonio P.,Gonzalez Hernandez J.I.Lo Curto G.Martins C.J.A.P.Nunes N.J.,Palle E.Pepe F.Seager S.Suarez Mascareno A.2024-11-06T20:05:14Z2023-06-30T09:55:56ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityphotometryvisible-astronomySmall planets located at the lower mode of the bimodal radius distribution are generally assumed to be composed of iron and silicates in a proportion similar to that of the Earth. However, recent discoveries are revealing a new group of low-density planets that are inconsistent with that description. We intend to confirm and characterize the TESS planet candidate TOI-244.01, which orbits the bright (K=7.97mag), nearby (d=22pc), and early-type (M2.5 V) M-dwarf star GJ 1018 with an orbital period of 7.4 days. We used Markov Chain Monte Carlo methods to model 57 precise radial velocity measurements acquired by the ESPRESSO spectrograph together with TESS photometry and complementary HARPS data. Our model includes a planetary component and Gaussian Processes aimed at modeling the correlated stellar and instrumental noise. We find TOI-244 b to be a super-Earth with a radius of R_p_=1.52+/-0.12R_{sun}_ and a mass of M_p_=2.66+/-0.31M_{sun}_. These values correspond to a density of {rho}=4.2+/-1.1g/cm^3^, which is below what would be expected for an Earth-like composition. We find that atmospheric loss processes may have been efficient to remove a potential primordial hydrogen envelope, but high mean-molecular weight volatiles such as water could have been retained. Our internal structure modeling suggests that TOI-244 b has a 479^+128^_-96_km thick hydrosphere over a 1.17+/-0.09R_{sun}_ solid structure composed of a Fe-rich core and a silicate-dominated mantle compatible with that of the Earth. On a population level, we find two tentative trends in the density-metallicity and density-insolation parameter space for the low-density super-Earths, which may hint at their composition. With a 8% precision in radius and 12% precision in mass, TOI-244 b is among the most precisely characterized super-Earths, which, together with the likely presence of an extended hydrosphere, makes it a key target for atmospheric observations.2023A&A...675A..52Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/675/A52CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/675/A52https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/675/A52http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/675/A52https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/675/A52https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/675/A52http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/675/A52GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/675/A52/tablea1TESS photometry of GJ 1018recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian datedtime.epochdoubleindexedPDCSAPTESS PDCSAPphot.countdoublee_PDCSAPTESS PDCSAP uncertaintystat.errordoublePDCSAPdetDetrended TESS PDCSAP from biweight methodphot.countdoublee_PDCSAPdetDetrended TESS PDCSAP uncertainty from biweight methodstat.errordoubleSectorSectorobs.fieldcharJ/A+A/675/A52/tablea2ESPRESSO radial velocities and activity indicators of GJ 1018recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRJDReduced Julian Date (JD-2400000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errordoubleFWHMFWHM of the CCFm/sphys.angSizedoublee_FWHMFWHM of the CCF uncertaintym/sstat.error;phys.angSizedoubleSindexS-index multiplied by a x1000 factorspect.indexdoublee_SindexS-index uncertainty multiplied by a x1000 factorstat.errordoubleContrastContrast of the CCF%phot.flux;arith.ratiodoublee_ContrastContrast of the CCF uncertainty%stat.errordoubleHalphaH-alpha activity indicator multiplied by a x1000 factorspect.index;em.line.Halphadoublee_HalphaH-alpha activity indicator uncertainty multiplied by a x1000 factorstat.error;spect.linedoubleNaDNaD activity indicator multiplied by a x1000 factorspect.indexdoublee_NaDNaD activity indicator uncertainty multiplied by a x1000 factorstat.errordoubleBISBIS-SPAN of the CCFphys.velocdoublee_BISBIS-SPAN of the CCF uncertaintystat.errordoubleJ/A+A/675/A52/tablea3HARPS radial velocities and activity indicators of GJ 1018recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRJDReduced Julian Date (JD-2400000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errordoubleFWHMFWHM of the CCFm/sphys.angSizedoublee_FWHMFWHM of the CCF uncertaintym/sstat.error;phys.angSizedoubleJ/A+A/675/A52/tablea4ASAS-SN photometry of GJ 1018 (Table A4)CameraCamerameta.id;instrcharFilterFiltermeta.id;instr.filtercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleFluxObserved fluxmJyphot.flux.density;em.optfloate_FluxObserved flux uncertaintymJystat.error;phot.fluxfloatJ/A+A/675/A52/tablea5Absolute fluxes of GJ 1018 in different filtersFilterFiltermeta.id;instr.filtercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAbsfluxAbsolute flux (in erg/cm^2^/s/{AA})10mW.m**-2.nm**-1phot.fluxdoublee_AbsfluxAbsolute flux uncertainty (in erg/cm^2^/s/{AA})10mW.m**-2.nm**-1stat.errordouble