2024/10/15 by Distler, Adam, Soares-Furtado, Melinda, Vanderburg, Andrew +18 · 1 citation
#Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2410.11990
We present the discovery and characterization of TOI-4364 b, a young mini-Neptune in the tidal tails of the Hyades cluster, identified through TESS transit observations and ground-based follow-up photometry. The planet orbits a bright M dwarf (K=9.1 mag) at a distance of 44 pc, with an orbital period of 5.42 days and an equilibrium temperature of 488+4-4 K. The host star's well-constrained age of 710 Myr makes TOI-4364 b an exceptional target for studying early planetary evolution around low-mass stars. We determined a planetary radius of 2.01+0.1-0.08 Earth radii, indicating that this planet is situated near the upper edge of the radius valley. This suggests that the planet retains a modest H/He envelope. As a result, TOI-4364 b provides a unique opportunity to explore the transition between rocky super-Earths and gas-rich mini-Neptunes at the early stages of evolution. Its radius, which may still evolve as a result of ongoing atmospheric cooling, contraction, and photoevaporation, further enhances its significance for understanding planetary development. Furthermore, TOI-4364 b possesses a moderately high Transmission Spectroscopy Metric of 44.2, positioning it as a viable candidate for atmospheric characterization with instruments such as JWST. This target has the potential to offer crucial insights into atmospheric retention and loss in young planetary systems.