2022ApJ...931..111S

Hot Jupiters orbiting rapidly rotating stars on inclined orbits undergo tidally induced nodal precession measurable over several years of observations. The Hot Jupiters WASP-33 b and KELT-9 b are particularly interesting targets because they are among the hottest planets found to date, orbiting relatively massive stars. Here, we analyze archival and new data that span 11 and 5 yr for WASP-33 b and KELT-9 b, respectively, in order to model and improve upon their tidal precession parameters. Our work confirms the nodal precession for WASP-33 b and presents the first clear detection of the precession of KELT-9 b. We determine that WASP-33 and KELT-9 have gravitational quadrupole moments ({6.3}_{-0.8}^{+1.2})\times {10}^{-5} and ({3.26}_{-0.80}^{+0.93})\times {10}^{-4}, respectively. We estimate the planets' precession periods to be {1460}_{-130}^{+170} yr and {890}_{-140}^{+200} yr, respectively, and that they will cease to transit their host stars around the years {2090}_{-10}^{+17} CE and {2074}_{-10}^{+12} CE, respectively. Additionally, we investigate both planets' tidal and orbital evolution, suggesting that a high-eccentricity tidal migration scenario is possible to produce both system architectures and that they will most likely not be engulfed by their hosts before the end of their main-sequence lifetimes.