The low density, hot Jupiter TOI-640 b is on a polar orbit

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Emil Knudstrup Simon H. Albrecht Davide Gandolfi Marcus L. Marcussen Elisa Goffo Luisa M. Serrano Fei Dai Seth Redfield Teruyuki Hirano Szilárd Csizmadia William D. Cochran Hans J. Deeg Malcolm Fridlund Kristine W. F. Lam John H. Livingston Rafael Luque Norio Narita Enric Palle Carina M. Persson Vincent Van Eylen

摘要： TOI-640 b is a hot, puffy Jupiter with a mass of $0.57 \pm 0.02$ M$_{\rm J}$ and radius of $1.72 \pm 0.05$ R$_{\rm J}$, orbiting a slightly evolved F-type star with a separation of $6.33^{+0.07}_{-0.06}$ R$_\star$. Through spectroscopic in-transit observations made with the HARPS spectrograph, we measured the Rossiter-McLaughlin effect, analysing both in-transit radial velocities and the distortion of the stellar spectral lines. From these observations, we find the host star to have a projected obliquity of $\lambda=184\pm3^\circ$. From the TESS light curve, we measured the stellar rotation period, allowing us to determine the stellar inclination, $i_\star=23^{+3\circ}_{-2}$, meaning we are viewing the star pole-on. Combining this with the orbital inclination allowed us to calculate the host star obliquity, $\psi=104\pm2^\circ$. TOI-640 b joins a group of planets orbiting over stellar poles within the range $80^\circ-125^\circ$. The origin of this orbital configuration is not well understood.

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