From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars
Abstract
Earth-sized planets transiting M dwarf stars present one of the best opportunities with current facilities for studying the atmospheric and bulk compositions of terrestrial worlds. Here, we statistically validate five new transiting Earth and super-Earth sized planets orbiting M dwarf stars using a combination of light curves from the Transiting Exoplanet Survey Satellite, multi-color observations from Palomar and Las Cumbres Observatory, high-resolution imaging, and stellar spectroscopy. The sample includes: TOI-5716 b, an Earth-sized planet (R_p = 0.96 0.05 Rearth) with a 6.766-day orbit around a metal-poor thin-disk star ([Fe/H] = -0.54 0.10); TOI-5728 b, a super-Earth (R_p = 1.31 0.05 Rearth) on an 11.497-day orbit; and TOI-5736 b, a larger planet (R_p = 1.56 0.07 Rearth) with an ultra-short period of just 0.649 days. We also statistically validate a multi-planet system, TOI-5489, hosting two similarly-sized super-Earths: TOI-5489 b (R_p = 1.40 0.05 R_earth) and TOI-5489 c (R_p = 1.28 0.07 R_earth) with orbital periods of 3.152 and 4.921 days, respectively. Due to their longer orbital periods, TOI-5716 b and TOI-5728 b both have equilibrium temperatures 400 K, making them useful test cases for studies of atmospheric mass loss. If TOI-5728 b is confirmed to have an Earth-like bulk composition, it would join the very small sample of rocky planets orbiting mid- to late-M dwarfs that lie below the cosmic shoreline and therefore may have retained high mean molecular weight atmospheres.
Cite
@article{arxiv.2512.11971,
title = {From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars},
author = {Jonathan Gomez Barrientos and Heather A. Knutson and Morgan Saidel and Michael Greklek-McKeon and W. Garrett Levine and Nicholas Saunders and Howard Isaacson and Renyu Hu and Karen A. Collins and David R. Ciardi and Polina A. Budnikova and Dmitry V. Cheryasov and Samuel W. Yee and Diogo Souto and Aida Behmard and Akihiko Fukui and Avi Shporer and Akanksha Khandelwal and Bob Massey and Brice-Oliver Demory and Catherine A. Clark and Chris Stockdale and Emily A. Gilbert and Enric Palle and Francis P. Wilkin and Felipe Murgas and Francis Zong Lang and Ilse Plauchu-Frayn and Jessie L. Christiansen and Jon M. Jenkins and Joseph D. Twicken and Keith Horne and Michaël Gillon and Monika Lendl and Michael B. Lund and Norio Narita and Pam Rowden and Ramotholo Sefako and Richard P. Schwarz and Steven Giacalone and Urs Schroffenegger and Yilen Gómez Maqueo Chew},
journal= {arXiv preprint arXiv:2512.11971},
year = {2025}
}
Comments
18 pages and 7 figures. Accepted for publication in AJ