• DOI:10.1093/mnras/stac620
• Corpus ID: 247244639

Nodal Precession of WASP-33b for Eleven Years by Doppler Tomographic and Transit Photometric Observations

@inproceedings{Watanabe2022NodalPO,
  title={Nodal Precession of WASP-33b for Eleven Years by Doppler Tomographic and Transit Photometric Observations},
  author={Noriharu Watanabe and Norio Narita and Enric Palle and Akihiko Fukui and Nobuhiko Kusakabe and Hannu Parviainen and Felipe Murgas and N. Casasayas-Barris and Marshall C. Johnson and Bun’ei Sato and John H. Livingston and Jerome P. de Leon and Mayuko Mori and Taku Nishiumi and Yuka Terada and Emma Esparza-Borges and Kiyoe Kawauchi},
  year={2022}
}

• N. Watanabe, N. Narita, +14 authors K. Kawauchi
• Published 3 March 2022
• Physics, Geology

WASP-33b, a hot Jupiter around a hot star, is a rare system in which nodal precession has been discovered. We updated the model for the nodal precession of WASP-33b by adding new observational points. Consequently, we found a motion of the nodal precession spanning 11 years. We present homogenous Doppler tomographic analyses of eight datasets, including two new datasets from TS23 and HIDES, obtained between 2008 and 2019, to illustrate the variations in the projected spin-orbit obliquity ofWASP-33b and its impact parameter.We also present its impact parameters based on photometric transit observations captured by MuSCAT in 2017 and MuSCAT2 in 2018. We derived its real spin-orbit obliquity ψ, stellar spin inclination is , and stellar gravitational quadrupole moment J2 from the time variation models of the two orbital parameters. We obtained ψ = 108.19+0.95 −0.97 deg, is = 58.3+4.6 −4.2 deg, and J2 = (1.36 +0.15 −0.12) × 10 −4. Our J2 value was slightly smaller than the theoretically predicted value, which may indicate that its actual stellar internal structure is different from the theoretical one. We derived the nodal precession speed ¤ θ = 0.507+0.025 −0.022 deg year −1, and its period Ppre = 709+33 −34 years, and found that WASP-33b transits in front of WASP-33 for only ∼ 20 % of the entire nodal precession period.