TOI-824 b: A New Planet on the Lower Edge of the Hot Neptune Desert


Abstract in English

We report the detection of a transiting hot Neptune exoplanet orbiting TOI-824 (SCR J1448-5735), a nearby (d = 64 pc) K4V star, using data from the textit{Transiting Exoplanet Survey Satellite} (TESS). The newly discovered planet has a radius, $R_{rm{p}}$ = 2.93 $pm$ 0.20 R$_{oplus}$, and an orbital period of 1.393 days. Radial velocity measurements using the Planet Finder Spectrograph (PFS) and the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph confirm the existence of the planet and we estimate its mass to be $M_{rm{p}}$ = 18.47 $pm$ 1.84 M$_{oplus}$. The planets mean density is $rho_{rm{p}}$ = 4.03$^{+0.98}_{-0.78}$ g cm$^{-3}$ making it more than twice as dense as Neptune. TOI-824 bs high equilibrium temperature makes the planet likely to have a cloud free atmosphere, and thus an excellent candidate for follow up atmospheric studies. The detectability of TOI-824 bs atmosphere from both ground and space is promising and could lead to the detailed characterization of the most irradiated, small planet at the edge of the hot Neptune desert that has retained its atmosphere to date.

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