TOI-700

system

TOI-700 is a quiet red dwarf 102 light-years away in Dorado, and a milestone for NASA's TESS mission: its planet d was the first Earth-size world TESS found in a star's habitable zone, and a second temperate Earth-size planet, e, was added in 2023. Four transiting planets in all.

Open in 3D viewSee TOI-700 in the live, interactive 3D map

Key facts

Type

Red dwarf + 4 planets

Distance

102 light-years

Confirmed planets

Habitable zone

2 Earth-size (d, e)

Science

Classification

Type: Single red-dwarf system (magnetically quiet)
Central star: TOI-700 — M2.5V red dwarf, ~3459 K, 0.42 M☉

Planets

Confirmed planets: 4 · b, c, d, e — all transiting
Habitable zone: d and e — both Earth-size and temperate

Distance

Distance: 102 light-years · in Dorado, the Swordfish

How we know

Note: Four confirmed transiting planets (NASA Exoplanet Archive, checked 2026-07-07), so their sizes are genuinely measured. Their masses are only ESTIMATED from those sizes (no dynamical measurement), so no density is quoted — an honest gap, not a guess. Placed at its real position, 102 light-years away.

Discovery & history

Name: A 'TESS Object of Interest' designation from NASA's Transiting Exoplanet Survey Satellite; the star has no proper name.

TESS found the inner three planets in 2020, including TOI-700 d — its first Earth-size habitable-zone planet. In 2023 a fourth, TOI-700 e — also Earth-size and also temperate — was confirmed, making this a rare system with two small planets in the habitable zone of a nearby, magnetically calm red dwarf.

Images

Artist's concept of TOI-700 d, TESS's first Earth-size habitable-zone planet — an artist's impression, not a photograph. — NASA's Goddard Space Flight Center (public domain) · Wikimedia Commons

Artist's concept of the Earth-size habitable-zone planet TOI-700 e — an artist's impression, not a photograph. — NASA/JPL-Caltech (public domain) · Wikimedia Commons

Images from open archives · credit shown per image