TOI-700

Star

TOI-700 — a cool, quiet red dwarf about 40% the Sun's mass, 102 light-years away in the southern constellation Dorado. Its magnetic calm makes its four transiting planets — two of them Earth-size and temperate — especially promising to study.

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

Key facts

Mass

8.25 × 10²⁹ kg

0.415 M☉

Radius

292,890 km

42% of the Sun's radius

Surface temperature

3,459 K (3,186 °C)

Luminosity

8.77 × 10²⁴ W

Spectral type

M2.5V (red dwarf)

Science

Physical

Mass: 8.25 × 10²⁹ kg · 0.415 M☉
Radius: 292,890 km · 42% of the Sun's radius
Density: 7,843 kg/m³ · 7.8× water; Computed from mass and radius
Spectral type: M2.5V (red dwarf)

Motion through space

Proper motion: 0.192 arcseconds per year · its drift across our sky; SIMBAD — 2020yCat.1350....0G, 2022ApJS..259...35A
Radial velocity: -4.8 km/s · approaching the Sun; SIMBAD — 2020yCat.1350....0G, 2022ApJS..259...35A
Speed across our line of sight: 28.3 km/s; Computed from proper motion and parallax
Speed through space, relative to the Sun: 28.7 km/s; Computed from proper motion, parallax and radial velocity

Rotation

Note: Unusually quiet for a red dwarf, with few flares — a gentler environment for its temperate planets.

Composition

By mass: A cool, magnetically quiet red dwarf about 40% the Sun's mass. Its low activity is a key reason its four transiting planets — two of them Earth-size and in the habitable zone — are strong targets for future atmosphere searches.

Temperature

Surface: 3,459 K (3,186 °C)

Radiation & temperature

Luminosity: 8.75 × 10²⁴ W · 0.0229 L☉
Surface temperature: 3,459 K (3,186 °C)
Peak wavelength: 838 nm · near-infrared (mostly invisible to the eye); Computed (Wien's law) from the surface temperature

Discovery & history

Method: Telescope
Name: A TESS-survey catalogue designation; no proper name.

Monitored by NASA's TESS from 2018; three planets were announced in 2020 and a fourth in 2023. Its low activity is a key reason its habitable-zone worlds are strong targets for future atmosphere searches.

Images

Where to find it — in Dorado, the Swordfish (IAU constellation chart). To the eye it is a single point of light; no telescope has imaged its surface. — IAU / Sky & Telescope, R. Sinnott & R. Fienberg (CC BY 3.0) · Wikimedia Commons

Images from open archives · credit shown per image