J/A+A/684/L17ivo://CDS.VizieR/J/A+A/684/L17doi:10.26093/cds/vizier.36849017CDSMantovan G.Malavolta L.Locci D.Polychroni D.Turrini D.Maggio A.,Desidera S.Spinelli R.Benatti S.Piotto G.Lanza A.F.Marzari F.,Sozzetti A.Damasso M.Nardiello D.Cabona L.D'Arpa M.Guilluy G.,Mancini L.Micela G.Nascimbeni V.Zingales T.2024-11-07T20:03:02Z2024-04-16T11:39:13ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityvisible-astronomyMulti-planet systems exhibit remarkable architectural diversity. However, short-period giant planets are typically isolated. Compact systems like TOI-5398, with an outer close-orbit giant and an inner small-size planet, are rare among systems containing short-period giants. TOI-5398's unusual architecture coupled with a young age (650+/-150Myr) makes it promising for measuring the original obliquity between the orbital plane of the giant and the stellar spin axis, to gain insights into its formation and orbital migration. We collected in-transit (plus suitable off-transit) observations of TOI-5398 b with HARPS-N at TNG on March 25, 2023, obtaining high-precision radial velocity time series that allowed us to measure the Rossiter-McLaughlin (RM) effect. From the RM effect modelling, we obtained a sky-projected obliquity of {lambda}=3.0^+6.8^_-4.2_deg for TOI-5398 b, consistent with the planet being aligned. Thanks to the stellar rotation period knowledge, we estimated the true 3D obliquity {psi}=(13.2+/-8.2)deg. Based on theoretical considerations, the orientation we measure is unaffected by tidal effects, offering a direct diagnostic for understanding the planetary system's formation path. The orbital characteristics of TOI-5398, with its compact architecture, eccentricity consistent with circular orbits, and hints of orbital alignment, appear more compatible with the disc-driven migration scenario. TOI-5398's relative youth (compared with similar compact systems) coupled with an exceptional suitability for transmission spectroscopy studies, presents an outstanding opportunity to establish a benchmark for exploring the disc-driven migration model.2024A&A...684L..17Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/684/L17CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/682/A129 : TOI-5398 spectroscopic time-series (Mantovan+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/684/L17https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/684/L17http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/684/L17https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/684/L17https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/684/L17http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/684/L17GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/684/L17/tablea1Radial velocity time-seriesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeBarycentric Julian date, TDB (BJD-2400000)dtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity uncertaintym/sstat.errorfloatPhase[on/off ] Transit phasemeta.codecharS/NSignal-to-noise ratio at 5460{AA}stat.snrfloat