GJ 1002

Star

GJ 1002 - a small, cool, very faint red dwarf 15.8 light-years away in Cetus, host to two planets that BOTH lie in its habitable zone. Because the star is so dim, that temperate zone lies very close in, where the two roughly Earth-mass worlds orbit in a matter of days to weeks.

Open in 3D viewSee GJ 1002 in the live, interactive 3D map

Key facts

Mass

2.39 × 10²⁹ kg

0.12 M☉

Radius

95,311 km

14% of the Sun's radius

Surface temperature

3,024 K (2,751 °C)

Luminosity

5.38 × 10²³ W

Spectral type

M5.5V (red dwarf)

Science

Physical

Mass: 2.39 × 10²⁹ kg · 0.12 M☉
Radius: 95,311 km · 14% of the Sun's radius
Density: 65,809 kg/m³ · 66× water; Computed from mass and radius
Spectral type: M5.5V (red dwarf)

Motion through space

Proper motion: 2.06 arcseconds per year · its drift across our sky; SIMBAD — 2020yCat.1350....0G, 2012AJ....144...99D
Radial velocity: -33.7 km/s · approaching the Sun; SIMBAD — 2020yCat.1350....0G, 2012AJ....144...99D
Speed across our line of sight: 47.3 km/s; Computed from proper motion and parallax
Speed through space, relative to the Sun: 58.1 km/s; Computed from proper motion, parallax and radial velocity

Rotation

Note: A slow, magnetically quiet rotator — essential for detecting the tiny signals of its two roughly Earth-mass planets.

Composition

By mass: A small, cool hydrogen/helium red dwarf about 0.12 solar mass and barely 0.1% of the Sun's light, 15.8 light-years away in Cetus. Because it is so dim, its habitable zone lies very close in, where its two planets orbit.

Temperature

Surface: 3,024 K (2,751 °C)

Radiation & temperature

Luminosity: 5.38 × 10²³ W · 0.00141 L☉
Surface temperature: 3,024 K (2,751 °C)
Peak wavelength: 958 nm · near-infrared (mostly invisible to the eye); Computed (Wien's law) from the surface temperature

Discovery & history

Method: Telescope
Name: A catalogue designation (Gliese-Jahreiss 1002).

A nearby low-mass red dwarf whose two planets were announced in 2022 by a team combining years of data from ESO's ESPRESSO and the CARMENES spectrographs - a delicate detection around a very faint star.

Images

Where to find it — in Cetus, the Sea Monster (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