70 Virginis b (abbreviated 70 Vir b) is an extrasolar planet approximately 60 light-years away in the constellation of Virgo. Announced in 1996 by Geoffrey Marcy and R. Paul Butler, 70 Virginis was one of the first stars confirmed to have planets orbiting it.[2] When first announced, 70 Virginis b was considered to be within its star's habitable zone (preferably in the "Goldilocks zone"), but it was later confirmed that the planet has an eccentric orbit, closer to its parent.

70 Virginis b

The exoplanet 70 Virginis b (min mass ~7.5 MJ) as rendered by Celestia
Discovery
Discovered by	Geoffrey Marcy R. Paul Butler
Discovery site	United States
Discovery date	17 January 1996[1]
Detection method	Doppler Spectroscopy
Orbital characteristics
Semi-major axis	0.484 ± 0.028 AU (72,400,000 ± 4,200,000 km)
Eccentricity	0.4007 ± 0.0035
Orbital period (sidereal)	116.6884 ± 0.0044 d
Time of periastron	2,447,239.82 ± 0.21
Argument of periastron	358.71 ± 0.54
Semi-amplitude	316.3 ± 1.7
Star	70 Virginis

Characteristics

70 Virginis b is a gas giant extrasolar planet that is 7.4 times the mass of Jupiter and is in an eccentric 116-day orbit about its host. Its surface gravity is expected to be about six to eight times that of Jupiter's. At the time of discovery in January 1996, it was believed that the star was only 29 ly away resulting in the star being less luminous based on its apparent magnitude. As a result, the planet's orbit was thought to be in the habitable zone and the planet was nicknamed Goldilocks (not too cold or too hot).[3]

The Hipparcos satellite later showed that the star was more distant from Earth and therefore brighter resulting in the planet being too hot to be in the habitable zone.[4]

A significant update to the 70 Virginis system revised the orbit of the planet and used interferometry to show that, although the host star is similar in mass and temperature to the Sun, it is almost twice the radius of the Sun.[5] The accuracy of these stellar parameters allowed the Habitable Zone to be calculated much more precisely, and orbital dynamics simulations show that a terrestrial planet can retain a stable orbit in the Habitable Zone despite the presence of the nearby eccentric giant planet.

See also

• 51 Pegasi b
• Tau Boötis b
• 55 Cancri b
• 47 Ursae Majoris b
• Upsilon Andromedae b

References

External links

• Jean Schneider (2011). "Notes for Planet 70 Vir b". Extrasolar Planets Encyclopaedia. Retrieved 10 October 2011.
• SolStation: 70 Virginis

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