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A Warm Belt Around Red Dwarfs express

Original: "Two temperate Earth- and Neptune-sized planets orbiting fully convective M dwarfs"
· Madison G. Scott, Georgina Dransfield, Mathilde Timmermans, Amaury H. M. J. Triaud, Benjamin V. Rackham, Khalid Barkaoui, Adam J. Burgasser, Karen A. Collins, Michaël Gillon, Steve B. Howell, Alan M. Levine, Francisco J. Pozuelos, Keivan G. Stassun, Carl Ziegler, Yilen Gomez Maqueo Chew, Catherine A. Clark, Yasmin Davis, Fatemeh Davoudi, Tansu Daylan, Brice-Olivier Demory, Dax Feliz, Akihiko Fukui, Maximilian N. Günther, Emmanuël Jehin, Florian Lienhard, Andrew W. Mann, Clàudia Janó Muñoz, Norio Narita, Peter P. Pedersen, Richard P. Schwarz, Avi Shporer, Abderahmane Soubkiou, Sebastián Zúñiga-Fernández
arXiv:2601.05799 · 2026-01-09 · CC BY 4.0 · 2 min
Exoplanets
Two new planets orbiting red dwarfs expand the list of worlds where it might be neither too hot nor too cold.

Two new planets are circling dim red stars. One is nearly the size of Earth, the other is three and a half times larger. Both lie in what astronomers call the warm zone: a region where starlight doesn't scorch the surface but also doesn't leave it in perpetual cold.

The host stars are red dwarfs, the most common stars in the galaxy. They are cooler and smaller than the Sun, so their planets can stay warm even when orbiting very close. The first planet, TOI-6716 b, completes an orbit around its star in 4.7 Earth days, while the second, TOI-7384 b, takes 6.2 days. For comparison, Mercury, the closest planet to the Sun, takes 88 days to complete an orbit.

The warm zone is an expanded version of the classic habitable zone. Instead of a narrow range of distances where water could be liquid on the surface, scientists consider a broader belt: from one-tenth to five times the amount of light Earth receives from the Sun. This approach helps avoid missing worlds that might look inhospitable by old standards but could retain heat in different ways.

Both planets receive about 4–5 times more light from their stars than Earth gets from the Sun. That's close to the hot edge of the warm zone. But if a planet has a thick atmosphere or clouds, some heat could be reflected, making surface conditions milder. TOI-6716 b is especially interesting: its radius is measured to within 6.8%, and it is considered a good candidate for studying rocky worlds with the James Webb Space Telescope.

Red dwarfs live long — tens and hundreds of billions of years. Their planets have had plenty of time for atmospheres, oceans, and even life to find their way. The two new finds add to the list of worlds worth a closer look.

Whole graph →

Red dwarfs are so dim that none of them is visible from Earth with the naked eye, even though they make up about 70% of all stars in our galaxy.

Scientists
Ludwig BoltzmannEnrico FermiPaul DiracFritz ZwickySubrahmanyan ChandrasekharIsaac Newton
Concepts
hot jupiter atmospheres trappist 1 exoplanets around red dwarfs sub neptune sub neptune formation europa super earth red dwarf habitability asteroid belt terrestrial exoplanet mercury earth radius multi planet systems hot jupiter neptune red dwarf planets Satellite layers