Confirmation of the hot super-Neptune TOI-672 b with NIRPS and HARPS and Insights into the Neptunian desert around M dwarfs
astro-ph.EP
/ Authors
Ares Osborn, Ryan Cloutier, Vincent Bourrier, Bennett Skinner, Nicole Gromek, Avidaan Srivastava, François Bouchy, Marion Cointepas, Neil J. Cook, Nicola Nari
and 58 more authors
Jose Manuel Almenara, 'Etienne Artigau, Xavier Bonfils, Charles Cadieux, Patrick Eggenberger, Alexandrine L'Heureux, Frédérique Baron, Susana C. C. Barros, Björn Benneke, Marta Bryan, Bruno L. Canto Martins, Nicolas B. Cowan, Eduardo Cristo, Xavier Delfosse, Jose Renan De Medeiros, René Doyon, Xavier Dumusque, David Ehrenreich, Jonay I. González Hernández, David Lafrenière, Izan de Castro Leão,
/ Abstract
The Neptunian desert is a distinct lack of Neptune-sized planets at short orbital periods, purportedly carved by photoevaporation and tidal circularization following high-eccentricity migration. Constraining these processes and how they vary across different host-star spectral types requires the detailed characterization of planets in the desert and around its boundaries. In this study, we confirm the planetary nature of a massive super-Neptune identified by TESS around the M0 dwarf TOI-672. We analyse photometry from TESS and ExTrA and precise radial velocity measurements taken with the recently commissioned Near-InfraRed Planet Searcher (NIRPS) and HARPS spectrographs. We measure the planetary orbital period, radius, and mass of 3.634 days, 5.31 +0.24 -0.26 Rearth, and 50.9 +4.5 -4.4 Mearth, respectively. Our findings place TOI-672 b within the Neptunian ridge, a pile-up of planets from 3--5 days at the Neptunian desert boundary. We then use a novel approach to determine the desert boundaries in period-radius space and instellation-radius space, and, for the first time, compare the Neptunian desert boundaries for planets orbiting FGK versus M dwarf stars. We determine that the boundary ridge shifts slightly inward from 3.3 +- 1.4 days for FGK host stars to 2.2 +- 1.0 days for M dwarf host stars; these values do not statistically significantly differ from each other, and the shift to shorter periods for M dwarf planets is smaller than theoretical photoevaporation models predict. We also find that TOI-672 b is a single-planet system within the sensitivity limits of our RV and TTV datasets.