J/A+A/673/A69ivo://CDS.VizieR/J/A+A/673/A69doi:10.26093/cds/vizier.36730069CDSLavie B.Bouchy F.Lovis C.Zapatero Osorio M.Deline A.Barros S.,Figueira P.Sozzetti A.Gonzalez Hernandez J.I.Lillo-Box J.,Rodrigues J.Mehner A.Damasso M.Adibekyan V.Alibert Y.,Allende Prieto C.Cristiani S.D'Odorico V.Di Marcantonio P.,Ehrenreich D.Genova Santos R.Lo Curto G.Martins C.J.A.P.Micela G.,Molaro P.Nunes N.Palle E.Pepe F.Poretti E.Rebolo R.Santos N.,Sousa S.Suarez Mascareno A.Tabrenero H.Udry S.2024-11-06T20:04:07Z2023-05-10T07:33:15ZCDS support team

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

cds-question@unistra.frmultiple-starsm-starsexoplanetsradial-velocityWe present radial velocity follow-up obtained with ESPRESSO of the M-type star LTT 1445A (TOI-455), for which a transiting planet b with an orbital period of 5.4 days was detected by TESS.We report the discovery of a second transiting planet (LTT 1445A c) and a third non-transiting candidate planet (LTT 1445A d) with orbital periods of 3.12 and 24.30 days, respectively. The host star is the main component of a triple M-dwarf system at a distance of 6.9pc. We used 84 ESPRESSO high-resolution spectra to determine accurate masses of 2.3+/-0.3M_{Earth}_ and 1.0+/-0.2M_{Earth}_ for planets b and c and a minimum mass of 2.7+/-0.7M_{Earth}_ for planet d. Based on its radius of 1.43+/-0.09 R_{Earth}_ as derived from the TESS observations, LTT 1445A b has a lower density than the Earth and may therefore hold a sizeable atmosphere, which makes it a prime target for the James Webb Space Telescope. We used a Bayesian inference approach with the nested sampling algorithm and a set of models to test the robustness of the retrieved physical values of the system. There is a probability of 85% that the transit of planet c is grazing, which results in a retrieved radius with large uncertainties at 1.60^+0.67^_-0.34_R_{Earth}_. LTT 1445A d orbits the inner boundary of the habitable zone of its host star and could be a prime target for the James Webb Space Telescope.2023A&A...673A..69Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/673/A69CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/163/168 : Photometry and radial velocity of LTT 1445A (Winters+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/673/A69https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/673/A69http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/673/A69https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/673/A69https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/673/A69http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/673/A69GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/673/A69/espressoLTT 1445A ESPRESSO observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDObservation date (BJD-2450000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity errorm/sstat.errordoubleFWHMFull width at half maximumm/sspect.line.widthdoublee_FWHMFull width at half maximum errorm/sstat.error;phys.angSizedoubleContrastContrastphot.flux;arith.ratiodoublee_ContrastContrast errorstat.errordoubleHalphaH{alpha} activity indexspect.indexdoublee_HalphaH{alpha} activity index errorstat.error;spect.linedoubleSS activity indexspect.indexdoublee_SS activity index errorstat.errordoubleNaDNaD activity indexmeta.code;spect.indexdoublee_NaDNaD activity index errorstat.errordoubleCaCa activity indexspect.indexdoublee_CaCa activity index errorstat.errordoubleRHK? R_HK_ activity indexphot.flux;arith.ratiodoublenullablee_RHK? R_HK_ activity index errorstat.errordoublenullable