HD 156668 b
Encyclopedia
HD 156668 b is an extrasolar planet
orbiting the star HD 156668
78.5 light-years away in the constellation Hercules
. It has a minimum mass of 3.1 Earth masses. At the time of discovery it was the second least massive planet discovered by the radial velocity method, subject to the mass/inclination degeneracy that affects radial velocity measurements. The only radial velocity planet less massive than this planet is Gliese 581 e
, which was discovered on April 21, 2009, and has a minimum mass of 1.94 Earth masses. In addition to this, it has the lowest semi-amplitude, or the speed of the stellar wobble
caused by planet's gravity tugging on the star determined by radial velocity, at 2.2 m/s. This planet was discovered on January 6, 2010; it is the 8th planet discovered in 2010 after the first five planets detected by Kepler
on January 4 and two planets around HD 9446
on January 5.
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...
orbiting the star HD 156668
HD 156668
HD 156668 is an orange dwarf star found in the Hercules constellation which is approximately 78.4 light-years away from the earth. The star has only about 27% of the Sun’s bolometric luminosity including a mass approximately 72% less and about 75% of its diameter...
78.5 light-years away in the constellation Hercules
Hercules (constellation)
Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
. It has a minimum mass of 3.1 Earth masses. At the time of discovery it was the second least massive planet discovered by the radial velocity method, subject to the mass/inclination degeneracy that affects radial velocity measurements. The only radial velocity planet less massive than this planet is Gliese 581 e
Gliese 581 e
Gliese 581 e or Gl 581 e is an extrasolar planet found around Gliese 581, an M3V red dwarf star approximately 20.5 light-years away from Earth in the constellation of Libra...
, which was discovered on April 21, 2009, and has a minimum mass of 1.94 Earth masses. In addition to this, it has the lowest semi-amplitude, or the speed of the stellar wobble
Stellar wobble
Stellar wobble is a variation in the position of a star due to the gravitational influence of another body orbiting it. Stellar wobble is visible as a Doppler shift in the star's spectrum or as a motion of the star in the plane of the sky...
caused by planet's gravity tugging on the star determined by radial velocity, at 2.2 m/s. This planet was discovered on January 6, 2010; it is the 8th planet discovered in 2010 after the first five planets detected by Kepler
Kepler Mission
The Kepler spacecraft is an American space observatory, the space-based portion of NASA's Kepler Mission to discover Earth-like planets orbiting other stars. The spacecraft is named in honor of the 17th-century German astronomer Johannes Kepler...
on January 4 and two planets around HD 9446
HD 9446
HD 9446 is a G5V class star, located about 172 light-years away in the constellation of Triangulum.- Planetary system :On 5 January 2010, scientists announced the discovery of two planets orbiting around HD 9446.- References :...
on January 5.