J/A+A/690/A349ivo://CDS.VizieR/J/A+A/690/A349doi:10.26093/cds/vizier.36900349CDSNascimbeni V.Borsato L.Leonardi P.Sousa S.G.Wilson T.G.Fortier A.,Heitzmann A.Mantovan G.Luque R.Zingales T.Piotto G.Alibert Y.,Alonso R.Barczy T.Barrado Navascues D.Barros S.C.Baumjohann W.,Beck T.Benz W.Billot N.Biondi F.Brandeker A.Broeg C.Busch M.-D.,Collier Cameron A.Correia A.C.M.Csizmadia Sz.Cubillos P.E.,Davies M.B.Deleuil M.Deline A.Delrez L.Demangeon O.D.S.,Demory B.-O.Derekas A.Edwards B.Ehrenreich D.Erikson A.Fossati L.,Fridlund M.Gandolfi D.Gazeas K.Gillon M.Guedel M.Guenther M.N.,Helling C.Isaak K.G.Kerschbaum F.Kiss L.Korth J.Lam K.W.F.,Laskar J.Lecavelier des Etangs A.Lelue A.Lendl M.Magrin D.,Maxted P.F.L.Merin B.Mordasini C.Olofsson G.Ottensamer R.,Pagano I.Palle E.Peter G.Pollacco D.Queloz D.Ragazzoni R.,Rando N.Rauer H.Ribas I.Santos N.C.Scandariato G.Segransan D.,Simon A.E.Smith A.M.S.Southworth R.Stalport M.Sulis S.,Szabo M.Gy.Udry S.Ulmer B.Van Grootel V.Venturini J.Villaver E.,Walton N.A.2025-02-18T20:01:28Z2024-10-22T10:55:10ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsphotometryvisible-astronomyK2-24 is a planetary system composed of two transiting low-density Neptunians locked in an almost perfect 2:1 resonance and showing large TTVs, i.e., an excellent laboratory to search for signatures of planetary migration. Previous studies performed with K2, Spitzer and RV data tentatively claimed a significant non-zero eccentricity for one or both planets, possibly high enough to challenge the scenario of pure disk migration through resonant capture. With 13 new CHEOPS light curves (seven of planet -b, six of planet -c), we carried out a global photometric and dynamical (RV+TTV) re-analysis by including all the available literature data as well. We got the most accurate set of planetary parameters to date for the K2-24 system, including radii and masses at 1% and 5% precision (now essentially limited by the uncertainty on stellar parameters) and non-zero eccentricities e_b_=0.0498^+0.0011^_-0.0018_, e_c_=0.0282^+0.0003^_-0.0007_ detected at very high significance for both planets. Such relatively large values imply the need for an additional physical mechanism of eccentricity excitation during or after the migration stage. Also, while the accuracy of the previous TTV model had drifted by up to 0.5 days at the current time, we constrained the orbital solution firmly enough to predict the forthcoming transits for the next ~15 years, thus enabling an efficient follow-up with top- level facilities such as JWST or ESPRESSO.2024A&A...690A.349Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A349CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/156/89 : K2-24 system RVs + predicted transit-times (Petigura+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A349https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A349http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A349https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A349https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A349http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A349GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/690/A349/table3Central transit time of K2-24b and K2-24crecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlanet[-b -c] Name of the planet (-b or -c)meta.id;meta.maincharInstInstrument namemeta.id;instrcharT0Central transit time T0, BJD-TDB standarddtime.epochdoublee_T0Symmetrized 1-sigma error on T0dstat.errordoubleIdID of the corresponding light curve (1)meta.idcharJ/A+A/690/A349/lcsLight curves of K2-24b and K2-24crecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlanet[-b -c] Name of the planet (-b or -c)meta.id;meta.maincharTimeTime of the observation, BJD-TDB standarddtime.epochdoubleFluxDetrended flux, normalizedphot.flux;arith.ratiodoublee_Flux1-sigma error on the detrended fluxstat.error;phot.fluxdoubleModelBest-fit PyORBIT modelstat.param;meta.modelleddoubleResFlux residuals from the best-fit modelstat.fit.residualdoubleNNumerical ID, for plottingmeta.idintIdID of the corresponding light curve (1)meta.idcharInstInstrument namemeta.id;instrcharT0Best-fit transit time T0, for stackingtime.epochdoubleJ/A+A/690/A349/predttTransit times of K2-24b and K2-24c predicted by our dynamic modele_T01-sigma error on T0dstat.errordoublePlanet[-b -c] Name of the planet (-b or -c)meta.id;meta.maincharT0BJDTDBT0 predicted by our model, in BJD-TDB standarddtime.epochdoubleT0JDT0 predicted by our model, in JDdtime.epochdoubleT0UTCT0 predicted by our model, in ISO UTC standardstime.epochnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint