Tau Ceti — Star in Cetus
About Tau Cet
Description
Tau Ceti is the closest solitary G-class star to the Sun — a G8 V dwarf 11.9 light-years away in the head of Cetus, magnitude 3.50. Slightly smaller and cooler than the Sun, it is metal-poor with about 28 % of the Sun's iron abundance. Long-term radial-velocity surveys have identified four candidate planets, two of which may orbit within the conservatively defined habitable zone.
Observing Tips
Unmistakable to the naked eye — one of the brightest stars in Cetus and easy to identify south-east of the head asterism. Best seen in autumn and early winter. The stellar disc itself shows nothing unusual at the eyepiece; the appeal is the knowledge of its proximity and possible worlds.
History
Long a fixture in the imagination of astronomers as a likely "Sun-like" host: in 1960 Frank Drake's Project Ozma pointed the 26-metre Green Bank dish at Tau Ceti and Epsilon Eridani — the first deliberate SETI search. No signal was found, but the choice of targets was prescient: both stars remain among the most observed nearby G-K dwarfs.
Fun Facts
Tau Ceti has an unusually massive debris disc — about ten times the Solar System's Kuiper Belt mass — which would mean any rocky planets there suffer a substantially higher impact rate from comets and asteroids than Earth does.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
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Compare Stars
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Spectral Classification
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Hertzsprung-Russell Diagram
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Stellar Lifecycle
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Blackbody Spectrum
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Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
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Stellar Fusion
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Exoplanets
4 known planets
View in 3D
| Planet | Radius | Mass | Period | Distance |
|---|---|---|---|---|
| tau Cet g | 1.18R⊕ | 1.8M⊕ | 20.0d | 12ly |
| tau Cet h | 1.19R⊕ | 1.8M⊕ | 49.4d | 12ly |
| tau Cet e | 1.81R⊕ | 3.9M⊕ | 162.9d | 12ly |
| tau Cet f | 1.81R⊕ | 3.9M⊕ | 1.7yr | 12ly |
Habitable Zone
Size & Mass Comparison
About exoplanets — how we find them and which host stars you can observe
Discover
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Light Travel Time Machine
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Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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