81 Ceti b
Encyclopedia
81 Ceti b is an extrasolar planet
approximately 317 light years away in the constellation
of Cetus
. It orbits the G-type giant star
81 Ceti
at an average distance of 2.5 AU
, taking about 2.6 years to revolve with 20.6% eccentricity
. This planet was discovered on July 3, 2008 by Sato et al., who used Doppler Spectroscopy
and found the wobbling of the star caused by the planet’s gravity during its revolution.
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 317 light years 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 Cetus
Cetus
Cetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...
. It orbits the G-type giant star
Giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
81 Ceti
81 Ceti
81 Ceti is a G-type giant star approximately 300 light years away in the constellation of Cetus. Based on its mass of 2.4 solar masses, it was an A-type star when it was a main-sequence star.- Planetary system :...
at an average distance of 2.5 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, taking about 2.6 years to revolve with 20.6% eccentricity
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...
. This planet was discovered on July 3, 2008 by Sato et al., who used Doppler Spectroscopy
Doppler spectroscopy
Doppler spectroscopy, also known as radial velocity measurement, is a spectroscopic method for finding extrasolar planets. It involves the observation of Doppler shifts in the spectrum of the star around which the planet orbits....
and found the wobbling of the star caused by the planet’s gravity during its revolution.