English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We validate the Transiting Exoplanet Survey Satellite (TESS) object ofinterest TOI-2266.01 (TIC 348911) as a small transiting planet (most likely asuper-Earth) orbiting a faint M5 dwarf ($V=16.54$) on a 2.33~d orbit. Thevalidation is based on an approach where multicolour transit light curves areused to robustly estimate the upper limit of the transiting object's radius.Our analysis uses SPOC-pipeline TESS light curves from Sectors 24, 25, 51, and52, simultaneous multicolour transit photometry observed with MuSCAT2, MuSCAT3,and HiPERCAM, and additional transit photometry observed with the LCOGTtelescopes. TOI-2266 b is found to be a planet with a radius of$1.54\pm\0.09\,R_\oplus$, which locates it at the edge of the transition zonebetween rocky planets, water-rich planets, and sub-Neptunes (the so-calledM~dwarf radius valley). The planet is amenable to ground-based radial velocitymass measurement with red-sensitive spectrographs installed in largetelescopes, such as MAROON-X and Keck Planet Finder (KPF), which makes it avaluable addition to a relatively small population of planets that can be usedto probe the physics of the transition zone. Further, the planet's orbitalperiod of 2.33 days places it inside a `keystone planet' wedge in theperiod-radius plane where competing planet formation scenarios make conflictingpredictions on how the radius valley depends on the orbital period. This makesthe planet also a welcome addition to the small population of planets that canbe used to test small-planet formation scenarios around M~dwarfs.

TOI-2266 b: a keystone super-Earth at the edge of the M dwarf radius valley