J/A+A/709/L15ivo://CDS.VizieR/J/A+A/709/L15CDSMantovan G.Malavolta L.Lanza A.F.Marzari F.Naponiello L.Biazzo K.,Cosentino R.D'Arpa M.C.Desidera S.Guilluy G.Nardiello D.,Sozzetti A.Vissapragada S.Aloisi R.Benatti S.Borsato L.Claudi R.,Jenkins S.Nascimbeni V.Piotto G.Zingales T.2026-05-19T14:14:26Z2026-05-12T08:52:57ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityvisible-astronomyThe obliquity between a planet's orbital axis and its host star's spin axis provides crucial insights into planetary formation and migration. Planets with scaled semi-major axes (a/R*) large enough to be unaffected by tidal alterations (tidally detached), offer a unique opportunity to study the original obliquity in which the system formed. We therefore observed TOI-1710 b (a/R*~36) in-transit using HARPS-N + GIANO-B, collecting high-precision radial velocities to measure the Rossiter-McLaughlin (RM) effect. Spectral analysis of the H{alpha} and HeI triple lines was also pursued to evaluate atmospheric photoevaporation. Using our knowledge of the star rotation period (21.5+/-0.2d), we estimated a true obliquity of psi=149^+11^_-10_deg, which indicates a retrograde motion and places TOI-1710 b among the most misaligned systems -- and the only one known orbiting a cool star in retrograde motion. The strong misalignment favours a high-eccentricity migration (HEM) origin for this low-density super-Neptune planet in the savanna region, challenging previous findings that claimed a minor role of HEM in this period-radius(-density) domain. Moreover, the strong misalignment and lack of a detected close stellar companion suggests a purely planetary post-migration misalignment, likely due to planet-planet scattering followed by planet-planet Kozai-Lidov oscillations and tidal circularisation.2026A&A...709L..15Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/709/L15CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/709/L15https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/709/L15http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/709/L15https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/709/L15https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/709/L15http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/709/L15GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/709/L15/tablea1TOI-1710: Radial velocity time-seriesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeBarycentric Julain day, TDB (BJD-2400000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errorfloat