Tau Ceti
Tau Ceti — a G8V star 11.9 light-years away in Cetus, and one of the nearest stars similar to the Sun: slightly smaller, cooler and dimmer, considerably older, and notably metal-poor (about a third the Sun's abundance of heavy elements). A long-time favourite in the search for life — though every planet claimed around it so far remains disputed and unconfirmed.
Key facts
Science
Physical
- Mass
- 1.55 × 10³⁰ kg · 0.78 M☉
- Radius
- 551,690 km · 79% of the Sun's radius
- Density
- 2,206 kg/m³ · 2.2× water
- Spectral type
- G8V (Sun-like, slightly cooler than the Sun's G2V)
Rotation
- Note
- Rotates about once every 34 days; magnetically quiet, which is partly why disputed planet signals are so hard to confirm.
Composition
- By mass
- A near Sun-like mix of hydrogen and helium, but markedly METAL-POOR — its iron abundance is only about a third of the Sun's ([Fe/H] ≈ −0.5). The low metal content may mean fewer rocky building blocks; it is also unusually quiet and stable for a Sun-like star.
Temperature
- Surface
- 5,320 K (5047 °C)
Radiation & temperature
- Luminosity
- 1.88 × 10²⁶ W · 0.49 L☉
- Surface temperature
- 5,320 K (5047 °C)
- Peak wavelength
- 545 nm · green-yellow visible light
Discovery & history
- Method
- Naked-eye star
- Name
- 'Tau Ceti' is the Bayer (Greek-letter) designation for a star in the constellation Cetus, the Sea Monster or Whale. It carries no widely-used proper name.
One of the brightest Sun-like stars visible to the naked eye, Tau Ceti has been known since antiquity as a star of Cetus, the Sea Monster. Its Sun-like character and nearness made it a prime target: in 1960 it was one of the two stars Frank Drake listened to in Project Ozma, the first modern radio search for extraterrestrial intelligence. Several planets have since been proposed (2012–2017), but all remain contested — the star's own activity mimics the tiny signals, and no claim is confirmed.
Images
Images from open archives · credit shown per image