J/A+A/692/A238ivo://CDS.VizieR/J/A+A/692/A238doi:10.26093/cds/vizier.36920238CDSLacedelli G.Palle E.Luque R.Cadieux C.Akana Murphy J.M.Murgas F.,Zapatero Osorio M.R.Tabernero H.M.Collins K.A.Watkins C.N.,L'Heureux A.Doyon R.Jankowski D.Nowak G.Artigau E.Batalha N.M.,Bean J.L.Bouchy F.Brady M.Canto Martins B.L.Carleo I.Cointepas M.,Conti D.M.Cook N.J.Crossfield I.J.M.Gonzalez Hernandez J.I.,Lewin P.Nari N.Nielsen L.D.Orell-Miquel J.Parc L.Schwarz R.P.,Srdoc G.Van Eylen V.2025-02-26T20:02:37Z2024-12-18T08:18:15ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityvisible-astronomyinfrared-astronomyThe exoplanet sub-Neptune population currently poses a conundrum. Are small-size planets volatile-rich cores without atmosphere, or are they rocky cores surrounded by H-He envelope? To test the different hypotheses from an observational point of view, a large sample of small-size planets with precise mass and radius measurements is the first necessary step. On top of that, much more information will likely be needed, including atmospheric characterisation and a demographic perspective on their bulk properties. We present here the concept and strategy of the THIRSTEE project, which aims at shedding light on the composition of the sub-Neptune population across stellar types by increasing their number and improving the accuracy of bulk density measurements, as well as investigating their atmospheres and performing statistical, demographic analysis. We report the first results of the program, characterising a new 2 planet system around the M-dwarf TOI-406. We analyse TESS and ground-based photometry together with high-precision ESPRESSO and NIRPS/HARPS radial velocities (RVs) to derive the orbital parameters and investigate the internal composition of the 2 planets orbiting TOI-406. TOI-406 hosts two planets with radii and masses of R_c_=1.32R_{Earth}_, M_c_=2.08M_{Earth}_ and R_b_=2.08R_{Earth}_, M_b_=6.57M_{Earth}_, orbiting with periods of 3.3 and 13.2 days, respectively. The inner planet is consistent with an Earth-like composition, while the external is compatible with multiple internal composition models, including volatile-rich planets without H/He atmospheres. The two planets are located in two distinct regions in the mass-density diagram, supporting the existence of a density gap among small exoplanets around M dwarfs. With an equilibrium temperature of only Teq=368K, TOI-406 b stands up as a particularly interesting target for atmospheric characterisation with JWST in the low-temperature regime.2024A&A...692A.238Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A238CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/692/A238https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/692/A238http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/692/A238https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/692/A238https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/692/A238http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/692/A238GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/A+A/692/A238/tablec1ESPRESSO RVs and activity indicatorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (TDB)dtime.epochdoubleRVRadival velocitym/sphys.veloc;pos.heliocentricfloate_RVRadial velocity uncertaintym/sstat.errorfloatdlwDifferential line widthm**2.s**-2spect.line.widthfloate_dlwDifferential line width uncertaintym**2.s**-2stat.errorfloatCRXChromatic indexm/sspect.indexfloate_CRXChromatic index uncertaintym/sstat.errorfloatNaISodium line index (doublet I)spect.index;spect.linefloate_NaISodium line index (doublet I) uncertaintystat.errorfloatNaIISodium line index (doublet II)spect.indexfloate_NaIISodium line index (doublet II) uncertaintystat.errorfloatHalphaH-alpha line indexspect.index;spect.linefloate_HalphaH-alpha line index uncertaintystat.error;spect.linefloatFWHMFull width half maximumm/sspect.line.widthfloate_FWHMFull width half maximum uncertaintym/sstat.error;phys.angSizefloatBisBisector spanm/sphys.velocfloate_BisBisector span uncertaintym/sstat.errorfloatSMWS-indexphot.flux;arith.ratiofloate_SMWS-index uncertaintystat.errorfloatContContrast of the CCFstat.fit.paramfloate_ContContrast of the CCF uncertaintystat.errorfloatJ/A+A/692/A238/tablec2NIRPS RVs and activity indicatorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (TDB)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errorfloatFWHMFull width half maximumm/sspect.line.widthfloate_FWHMFull width half maximum uncertaintym/sstat.error;phys.angSizefloatContContrast of the CCFstat.fit.paramdoublee_ContContrast of the CCF uncertaintystat.errordoubleJ/A+A/692/A238/tablec3HARPS RVs and activity indicatorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Date (TDB)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errorfloatFWHMFull width half maximumm/sspect.line.widthfloate_FWHMFull width half maximum uncertaintym/sstat.error;phys.angSizefloatContContrast of the CCFstat.fit.paramfloate_ContContrast of the CCF uncertaintystat.errorfloat