Epsilon Indi
Star
Epsilon Indi - a bright orange dwarf (K5V) just 11.9 light-years away in Indus, one of the nearest stars visible to the naked eye. It hosts a cold super-Jupiter (Epsilon Indi Ab) on a wide orbit, and - far out at ~1,460 AU - a pair of brown dwarfs, among the nearest known.
Open in 3D viewSee Epsilon Indi in the live, interactive 3D map
Key facts
Mass
1.55 × 10³⁰ kg
0.781 M☉
Radius
472,380 km
68% of the Sun's radius
Surface temperature
4,760 K (4,487 °C)
Luminosity
9.15 × 10²⁵ W
Spectral type
K5V (orange dwarf)
Science
Physical
- Mass
- 1.55 × 10³⁰ kg · 0.781 M☉
- Radius
- 472,380 km · 68% of the Sun's radius
- Density
- 3,518 kg/m³ · 3.5× water
- Computed from mass and radius
- Spectral type
- K5V (orange dwarf)
Motion through space
- Proper motion
- 4.71 arcseconds per year · its drift across our sky
- SIMBAD — 2020yCat.1350....0G, 2018A&A...616A...7S
- Radial velocity
- -40.0 km/s · approaching the Sun
- SIMBAD — 2020yCat.1350....0G, 2018A&A...616A...7S
- Speed across our line of sight
- 81.2 km/s
- Computed from proper motion and parallax
- Speed through space, relative to the Sun
- 90.5 km/s
- Computed from proper motion, parallax and radial velocity
Rotation
- Note
- Rotates about once every 35 days.
Composition
- By mass
- An orange main-sequence star about 78% of the Sun's mass and a quarter of its light, metal-rich and moderately active.
Temperature
- Surface
- 4,760 K (4,487 °C)
Radiation & temperature
- Luminosity
- 9.15 × 10²⁵ W · 0.239 L☉
- Surface temperature
- 4,760 K (4,487 °C)
- Peak wavelength
- 609 nm · orange light
- Computed (Wien's law) from the surface temperature
Discovery & history
- Method
- Naked-eye star
- Name
- 'Epsilon Indi' is the Bayer designation for a star in Indus, the Indian. It has no widely-used proper name.
Known since antiquity as a star of the southern sky, Epsilon Indi was long prized as a Sun-like neighbour. Its brown-dwarf companions were found in 2003; a giant planet's slow radial-velocity wobble was tracked over two decades, and in 2024 JWST directly imaged the planet - one of the first images of a planet first found by the wobble it induces.
Images
Images from open archives · credit shown per image