An eccentric Jupiter is a Jovian planet that orbits its star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 in an eccentric

Orbital eccentricity

The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...

 orbit. Eccentric Jupiters may disqualify a planetary system

Planetary system

A planetary system consists of the various non-stellar objects orbiting a star such as planets, dwarf planets , asteroids, meteoroids, comets, and cosmic dust...

 from having Earth-like planets

Earth analog

An Earth analog is a theoretical other planet with conditions similar to Earth....

 in it because a massive gas giant

Gas giant

A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...

 with an eccentric orbit may remove all Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 mass planets from the habitable zone

Habitable zone

In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

.

To date, it appears that approximately 7% of all star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

s (half of the known planetary systems) have an eccentric Jupiter (e > 0.1), making these planets more common than Hot Jupiters

Hot Jupiter

Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...

.

Out of the more than 200 extrasolar planet discoveries (as of 2006), 15 planets have high eccentricities (e > 0.6).

The typical exoplanet with an orbital period greater than 5 days has a median eccentricity of 0.23.

Possible habitable zone

Habitable zone

In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

 planets near eccentric Jupiters:

Planet	SMA Semi-major axis The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...	ecc Orbital eccentricity The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...	MJ Jupiter mass Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....	Notes
HD 3651 b 54 Piscium b 54 Piscium b , occasionally catalogued as 54 Piscium Ab in order to differentiate from the brown dwarf in the system, is an extrasolar planet approximately 36 light-years away in the constellation of Pisces. The planet was discovered orbiting the orange dwarf star 54 Piscium...	0.29	0.61	0.22	Might allow for planets at or beyond 0.6 AU
HD 37605 b HD 37605 b HD 37605 b is an extrasolar planet that has nearly three times more mass than Jupiter. It orbits close to the star, taking 54 days to revolve around the parent star HD 37605. Its orbit is highly eccentric, around 74%...	0.26	0.73	2.84	Might allow for planets at or beyond 0.8 AU
HD 45350 b HD 45350 b HD 45350 b is an extrasolar planet located approximately 160 light-years away in the constellation of Auriga. It has a minimum mass about 1.79 times that of Jupiter...	1.92	0.77	1.79	restricted stable orbits to the innermost 0.2 AU
HD 80606 b HD 80606 b HD 80606 b is a superjovian planet 190 light-years distant in the constellation of Ursa Major. The planet was discovered orbiting the star Struve 1341 B in April 2001 by a team led by Michel Mayor and Didier Queloz. Based on its mass, at 4 times that of Jupiter, it is a gas giant...	0.45	0.93	4.0	only beyond 1.75 AU did test particles remain
HD 89744 b HD 89744 b HD 89744 b is an eccentric Jupiter extrasolar planet orbiting the star HD 89744.In a simulation of a 10 million year span, this planet swept away all test particles "except for a narrow region near the 8:3 resonance". There can be no planets in this star's habitable zone. Observation has ruled out...	0.93	0.67	8.58	No planets in the habitable zone
16 Cygni Bb 16 Cygni Bb 16 Cygni Bb or 16 Cyg Bb is an extrasolar planet approximately 70 light-years away in the constellation of Cygnus. The planet was discovered orbiting the sun-like star 16 Cygni B, one of two solar-mass components of the triple star system 16 Cygni...	1.68	0.68	1.68	No planets in the habitable zone