The Spin–Orbit Misalignment of TOI-1842b: The First Measurement of the Rossiter–McLaughlin Effect for a Warm Sub-Saturn around a Massive Star

The mechanisms responsible for generating spin-orbit misalignments in exoplanetary systems are still not fully understood. It is unclear whether these related to the migration of hot Jupiters or a consequence general star and planet formation processes. One promising method address this question constrain distribution angle measurements broader range planets beyond Jupiters. In work, we present sky-projected obliquity ($\lambda=-68.1_{-14.7}^{+21.2} \,^{\circ}$) warm sub-Saturn TOI-1842b, obtained through measurement Rossiter-McLaughlin effect using WIYN/NEID. Using projected obliquity, stellar rotation period from TESS light curve, velocity spectral analysis, infer 3D ($\psi$) be $\psi=73.3^{+16.3}_{-12.9} \,^{\circ}$. As first determination made sub-Saturn-mass around massive ($M_{\rm *}=1.45 \,{\rm M_\odot}$) star, our result presents an opportunity examine orbital geometries new regimes planetary systems. When combined with archival measurements, observations TOI-1842b support hypothesis that previously established prevalence misaligned hot, stars may driven by planet-planet dynamical interactions. systems, multiple gas giants more likely form can then dynamically interact each other excite misalignments.