A Mini-Neptune and a Venus-Zone Planet in the Radius Valley Orbiting the Nearby M2-dwarf TOI-1266: Validation with the Habitable-zone Planet Finder

Gudmundur Stefansson; Ravi Kopparapu; Andrea Lin; Suvrath Mahadevan; Caleb Cañas; Shubham Kanodia; Joe Ninan; William Cochran; Michael Endl; Leslie Hebb; John Wisniewski; Arvind Gupta; Mark Everett; Chad Bender; Scott Diddams; Eric Ford; Connor Fredrick; Samuel Halverson; Fred Hearty; Eric Levi; Marissa Maney; Andrew Metcalf; Andrew Monson; Lawrence Ramsey; Paul Robertson; Arpita Roy; Christian Schwab; Ryan Terrien; Jason Wright

arXiv · 2006.11180

A Mini-Neptune and a Venus-Zone Planet in the Radius Valley Orbiting the Nearby M2-dwarf TOI-1266: Validation with the Habitable-zone Planet Finder

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Abstract

We report on the validation of two planets orbiting the nearby (36pc) M2 dwarf TOI-1266 observed by the TESS mission. The inner planet is sub-Neptune-sized ($R=2.46 \pm 0.08 R_\oplus$) with an orbital period of 10.9 days. The outer planet has a radius of $1.67_{-0.11}^{+0.09} R_\oplus$ and resides in the exoplanet Radius Valley---the transition region between rocky and gaseous planets. With an orbital period of 18.8 days, the outer planet receives an insolation flux of 2.4 times that of Earth, similar to the insolation of Venus. Using precision near-infrared radial velocities with the Habitable-zone Planet Finder Spectrograph, we place upper mass limits of $15.9 M_\oplus$ and $6.4 M_\oplus$ at 95% confidence for the inner and outer planet, respectively. A more precise mass constraint of planet c, achievable with current RV instruments given the host star brightness (V=12.9, J=9.7), will yield further insights into the dominant processes sculpting the exoplanet Radius Valley.

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Gudmundur Stefansson, Ravi Kopparapu, Andrea Lin, Suvrath Mahadevan, Caleb Cañas, Shubham Kanodia, Joe Ninan, William Cochran, Michael Endl, Leslie Hebb, John Wisniewski, Arvind Gupta, Mark Everett, Chad Bender, Scott Diddams, Eric Ford, Connor Fredrick, Samuel Halverson, Fred Hearty, Eric Levi, Marissa Maney, Andrew Metcalf, Andrew Monson, Lawrence Ramsey, Paul Robertson, Arpita Roy, Christian Schwab, Ryan Terrien, Jason Wright. 2020-06-19. A Mini-Neptune and a Venus-Zone Planet in the Radius Valley Orbiting the Nearby M2-dwarf TOI-1266: Validation with the Habitable-zone Planet Finder. https://arxiv.org/abs/2006.11180

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