AB Mass Center0.0........................
94 Ceti A431,4700.26661.31.05......1.23-1.35
Planet "b",10.........
Disrupted H.Z. A2.112.690..................
94 Ceti B1081,4700.26660.53>0.10.........
Habitable Zone B0.100.450..................

NOTE: This animation attempts to relate the possible orbits of 94 Ceti AB (and their current, if brief, habitable zone) to their common center of mass. Although the initial display shows the system's actual orbital tilt (at an inclination of 66°) from the visual perspective of an observer on Earth, the orbital inclination of the known planetary companion "b" around Star A may be be different from that of the habitable zone orbit depicted here.

According to the new Sixth Catalog of Orbits of Visual Binaries, Stars A and B have an average separation of 151 AUs (6.77" at a HIPPARCOS distance estimate of 73.0 light-years -- 3.3" at 231° in 1958). Inclined at 114.10° (Sixth Catalog) or 66° (original source) to Earth's line of sight, their eccentric orbit (e= 0.26) takes about 1,470 years to complete (Alan Hale, 1994, pages 312 and 314).

On August 7, 2000, a team of astronomers (Dominique Naef, Francisco Pepe, Michel Mayor, Nuno C. Santos, Didier Queloz, Stephane Udry, and M. Burnet) announced the discovery of a Jupiter-like planet around this Sun-like star (Observatoire de Genève and exoplanets.org). Planet "b" has at least 1.66 times of Jupiter's mass. It moves around Star A at an average distance of 1.19 AUs (a semi-major axis between the orbital distances of Earth and Mars) in an elliptical orbit (e=0.20) that takes 454 days or over 1.2 years to complete.

The orbit of an Earth-like planet (with liquid water) around Star A may be centered around 2.11 AUs -- within the inner reaches of the Main Asteroid Belt in the Solar System -- with an orbital period of 2.69 years. However, the presence of planet b in an eccentric orbit with an average distance of 1.19 AUs would probably disrupt the orbital stability of an Earth-type planet in Star A's water zone. Astronomers would find it very difficult to detect an Earth-type planet in the water zone of this star using present methods.

The orbit of an Earth-like planet (with liquid water) around Star B may be centered around 0.102 AUs -- well within the orbital distance of Mercury in the Solar System -- with an orbital period of 16.5 days. Hence, such a planet is likely to be tidally locked with Star B with perpetual daylight on one side.


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