J/A+A/690/A79ivo://CDS.VizieR/J/A+A/690/A79doi:10.26093/cds/vizier.36900079CDSGonzalez Hernandez J.I.Suarez Mascareno A.Silva A.M.Stefanov A.K.,Faria J.P.Tabernero H.M.Sozzetti A.Rebolo R.Pepe F.Santos N.C.,Cristiani S.Lovis C.Dumusque X.Figueira P.Lillo-Box J.Nari N.,Benatti S.Hobson M.J.Castro-Gonzalez A.Allart R.Passegger V.M.,Zapatero Osorio M.-R.Adibekyan V.Alibert Y.Allende Prieto C.,Bouchy F.Damasso M.D'Odorico V.Di Marcantonio P.Ehrenreich D.,Lo Curto G.Genova Santos R.Martins C.J.A.P.Mehner A.Micela G.,Molaro P.Nunes N.Palle E.Sousa S.G.Udry S.2025-02-12T20:01:17Z2024-10-01T11:44:20ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityvisible-astronomyESPRESSO guaranteed time observations (GTO) at the 8.2m-VLT telescope aimed at finding Earth-like exoplanets in the habitable zone of nearby stars. Barnard's star is a primary target within the ESPRESSO GTO as it is the second closest neighbour to our Sun after the alpha Centauri stellar system. We present here a large set of 156 ESPRESSO observations of Barnard's star taken over four years with the goal of exploring periods shorter than 50 days, thus including the habitable zone. The analysis of ESPRESSO data using Gaussian process (GP) to model stellar activity suggests a long-term activity cycle at 3200d and confirms stellar activity due to rotation at 140d as the dominant source of RV variations. These results are supported by adding publicly available HARPS, HARPS-N and CARMENES data. ESPRESSO RVs do not support the existence of the previously reported candidate planet at 233 d. Results. ESPRESSO RVs reveal, after subtracting the GP model, several short period candidate planet signals at periods 3.15d, 4.12d, 2.34d and 6.74d. We confirm the 3.15d signal as a sub-Earth mass planet, with a semi-amplitude of 55+/-7cm/s, leading to a planet minimum mass m_p_sini of 0.37+/-0.05M_{Earth}_, about three times the mass of Mars. ESPRESSO RVs provide hints of a candidate system with four sub-Earth mass planets in circular orbits with semi-amplitudes from 20 to 47cm/s, thus corresponding to minimum masses in the range 0.17-0.32M_{Earth}_. The sub-Earth mass planet at 3.1533+/-0.0006d is in a closely circular orbit with a semi-major axis of 0.0229+/-0.0003AU, thus located inner to the habitable zone of Barnard's star, with an equilibrium temperature of 400K. The other three candidate signals will require additional ESPRESSO observations to be confirmed as a compact short-period planet system orbiting Barnard's star inner to its habitable zone.2024A&A...690A..79Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A79CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/764/131 : Long-term monitoring of Barnard's star velocityJ/other/Nat/563.365 : Barnard's star radial velocity curve (Ribas+, 2018)J/AJ/162/61 : Radial velocity follow up of Barnard's star with HPFhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A79https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A79http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A79https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A79https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A79http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A79GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/690/A79/table5TM RV and CCF FHWM measurements of ESPRESSO datasetsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian date (BJD-2450000)dtime.epochdoubleRVRadial velocity from template-matching (TM)m/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity from template-matching (TM) errorm/sstat.errordoubleFWHMFull width at half maximum of the CCFm/sphys.angSizedoublee_FWHMFull width at half maximum of the CCF errorm/sstat.error;phys.angSizedoubleSubsetSubset of data (1)meta.idcharJ/A+A/690/A79/tabled3TM RV and CCF FHWM measurements of all datasetsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian date (BJD-2450000)dtime.epochdoubleRVRadial velocity from template-matching (TM)m/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity from template-matching (TM) errorm/sstat.errordoubleFWHMFull width at half maximum of the CCFm/sphys.angSizedoublee_FWHMFull width at half maximum of the CCF errorm/sstat.error;phys.angSizedoubleSubsetSubset of data (1)meta.idchar