File:Tau ceti planetary orbits.svg

English: This diagram depicts the orbits of the planets orbiting the star Tau Ceti. Orbital parameters are taken from:

Tuomi et al. (2012) "Signals embedded in the radial velocity noise. Periodic variations in the tau Ceti velocities" https://arxiv.org/abs/1212.4277

Planets e and f which are only detected in the combined datasets are shown with dotted orbits to indicate their less-certain status. For orbital positions the mean anomalies were computed from the time of periastron values given in table 9 of that paper. The symbols for the star and the planets are not drawn to scale.

The habitable zone is plotted according to the formulae given in:

Underwood, Jones and Sleep (2003) "The evolution of habitable zones during stellar lifetimes and its implications on the search for extraterrestrial life" https://arxiv.org/abs/astro-ph/0312522

• Red = Recent Venus (inner) – Runaway greenhouse (outer)
• Yellow = Runaway greenhouse (inner) – Water loss (outer)
• Green = Water loss (inner) – First CO₂ condensation (outer) = most conservative habitable zone
• Cyan = First CO₂ condensation (inner) – Maximum greenhouse (outer)
• Blue = Maximum greenhouse (inner) – Early Mars (outer)

The debris disc is too large to be shown on this scale.