http://arxiv.org/abs/2304.06655
We report the discovery of a hot ($T_{\rm eq}$ $\approx$ 1055 K) planet in the small planet radius valley transiting the Sun-like star TOI-733, as part of the KESPRINT follow-up program of TESS planets carried out with the HARPS spectrograph. TESS photometry from sectors 9 and 36 yields an orbital period of $P_{\rm orb}$ = $4.884765 { – 2.4e-5 } ^ { + 1.9e-5 }$ days and a radius of $R{\mathrm{p}}$ = $1.992 { – 0.090 } ^ { + 0.085 }$ $R{\oplus}$. Multi-dimensional Gaussian process modelling of the radial velocity measurements from HARPS and activity indicators, gives a semi-amplitude of $K$ = $2.23 \pm 0.26 $ m s$^{-1}$, translating into a planet mass of $M_{\mathrm{p}}$ = $5.72 { – 0.68 } ^ { + 0.70 }$ $M{\oplus}$. These parameters imply that the planet is of moderate density ($\rho_\mathrm{p}$ = $3.98 _{ – 0.66 } ^ { + 0.77 }$ g cm$^{-3}$) and place it in the transition region between rocky and volatile-rich planets with H/He-dominated envelopes on the mass-radius diagram. Combining these with stellar parameters and abundances, we calculate planet interior and atmosphere models, which in turn suggest that TOI-733 b has a volatile-enriched, most likely secondary outer envelope, and may represent a highly irradiated ocean world – one of only a few such planets around G-type stars that are well-characterised.
I. Georgieva, C. Persson, E. Goffo, et. al.
Fri, 14 Apr 23
15/64
Comments: Accepted for publication in A&A