13:45 〜 15:15
[PEM11-P13] Nodal Precession of a Hot Jupiter Transiting Edge of a Late A Type Star: TOI-1518 b
キーワード：ホットジュピター、高温星、トランジット、惑星軌道歳差
About 20 hot Jupiters around hot stars, whose effective temperatures are above 7000K, have been discovered. Their orbital axes tend to be misaligned with spin axes of their host stars, and the host stars are oblate due to their fast rotations (Albrecht et al. 2022). These planetary systems occur nodal precession; the orbital axis rotates around the stellar spin axis. This precession moves the transit trajectory. Therefore, when the orbit is nearly polar to the stellar spin, we can detect the changes of the apparent distance between the transit trajectory and the center of host star, impact parameter b.
TOI-1518b, a hot Jupiter around an A-type star is one of the few planetary systems that transit the edge of the stellar surface (b~0.9) among hot Jupiters around hot stars (Cabot et al. 2021). The host star's high rotation speed (~85 km/s) and the planet's nearly polar orbit (~120 deg) cause a nodal precession. If the orbit shifts toward a larger b, the transit trajectory moves further toward the edge, which may prevent the transit observation of TOI-1518b in a few decade.
In this study, we calculated b for each year from photometric data of TOI-1518 acquired in 2019 and 2022 with the space telescope TESS, and b in 2020 from spectral transit data of TOI-1518b acquired in 2020 with the high dispersion spectrograph CARMENES. We then derived the change of b of TOI-1518b. The results show that the value of b is decreasing with db/dt=-0.0110±0.0019 year-1, indicating that the transit orbit is moving toward the center of the stellar surface at the present time. TOI-1518b is the fourth planetary system in which nodal precession has been detected. In this presentation, we will discuss the behavior of the nodal precession of TOI-1518b and the parameters obtained from this precession.
TOI-1518b, a hot Jupiter around an A-type star is one of the few planetary systems that transit the edge of the stellar surface (b~0.9) among hot Jupiters around hot stars (Cabot et al. 2021). The host star's high rotation speed (~85 km/s) and the planet's nearly polar orbit (~120 deg) cause a nodal precession. If the orbit shifts toward a larger b, the transit trajectory moves further toward the edge, which may prevent the transit observation of TOI-1518b in a few decade.
In this study, we calculated b for each year from photometric data of TOI-1518 acquired in 2019 and 2022 with the space telescope TESS, and b in 2020 from spectral transit data of TOI-1518b acquired in 2020 with the high dispersion spectrograph CARMENES. We then derived the change of b of TOI-1518b. The results show that the value of b is decreasing with db/dt=-0.0110±0.0019 year-1, indicating that the transit orbit is moving toward the center of the stellar surface at the present time. TOI-1518b is the fourth planetary system in which nodal precession has been detected. In this presentation, we will discuss the behavior of the nodal precession of TOI-1518b and the parameters obtained from this precession.