70 Virginis b
Encyclopedia
70 Virginis b is an extrasolar planet
approximately 60 light-year
s 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. 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.
extrasolar planet
that is 7.5 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).
The Hipparcos
satellite later showed that the star was more distant and therefore brighter resulting in the planet being too hot to be in the habitable zone.
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
approximately 60 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Virgo
Virgo (constellation)
Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...
. Announced in 1996 by Geoffrey Marcy
Geoffrey Marcy
Geoffrey W. Marcy is an American astronomer, who is currently Professor of Astronomy at the University of California, Berkeley, famous for discovering more extrasolar planets than anyone else, 70 out of the first 100 to be discovered, along with R...
and R. Paul Butler
R. Paul Butler
R. Paul Butler is an astronomer who searches for extrasolar planets.He received a BA and an MS from San Francisco State University, completing a Master's thesis with Geoffrey Marcy, and then completed his doctoral studies at the University of Maryland, College Park in 1993...
, 70 Virginis
70 Virginis
70 Virginis is a yellow dwarf star approximately 59 light-years away in the constellation Virgo. It is rather unusually bright for its spectral type and may be just starting to evolve into the subgiant phase....
was one of the first stars confirmed to have planets orbiting it. When first announced, 70 Virginis b was considered to be within its star's 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...
(preferably in the "Goldilocks zone"), but it was later confirmed that the planet has an eccentric orbit, closer to its parent.
Characteristics
70 Virginis b is a gas giantGas 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...
extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
that is 7.5 times the mass of Jupiter and is in an eccentric 116 day orbit about its host. Its surface gravity
Surface gravity
The surface gravity, g, of an astronomical or other object is the gravitational acceleration experienced at its surface. The surface gravity may be thought of as the acceleration due to gravity experienced by a hypothetical test particle which is very close to the object's surface and which, in...
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
Luminosity
Luminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...
based on its apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
. As a result the planet's orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
was thought to be in 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...
and the planet was nicknamed Goldilocks (not too cold or too hot).
The Hipparcos
Hipparcos
Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky...
satellite later showed that the star was more distant and therefore brighter resulting in the planet being too hot to be in the habitable zone.
See also
- 51 Pegasi b51 Pegasi b51 Pegasi b , sometimes though unofficially named Bellerophon, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus...
- Tau Boötis b
- 55 Cancri b55 Cancri b55 Cancri b is an extrasolar planet orbiting the Sun-like star 55 Cancri A every 14.65 days. It is the second planet in order of distance from its star, and is an example of a hot Jupiter. Discovered in 1996 by Geoffrey Marcy and R...
- 47 Ursae Majoris b47 Ursae Majoris b47 Ursae Majoris b is an extrasolar planet approximately 46 light-years from Earth in the constellation of Ursa Major. The planet was discovered located in a long-period orbit around the star 47 Ursae Majoris in January 1996 and as of 2011 is the innermost of three known planets in its planetary...
- Upsilon Andromedae bUpsilon Andromedae bUpsilon Andromedae b, occasionally referred to as Upsilon Andromedae Ab , is an extrasolar planet approximately 44 light-years away from Earth in the constellation of Andromeda . The planet was discovered orbiting the Solar twin star, Upsilon Andromedae, approximately every five days...