![]() 16 Cygni Bb rendered in Celestia | |
Discovery | |
---|---|
Discovered by | William D. Cochran, Artie P. Hatzes, R. Paul Butler, Geoff Marcy |
Discovery site | United States |
Discovery date | 22 October 1996 |
Radial velocity | |
Orbital characteristics | |
1.681 ± 0.097 AU (251,500,000 ± 14,500,000 km) | |
Eccentricity | 0.689 ± 0.011 [1] |
798.5 ± 1.0 d | |
Inclination | 45 or 135 [1] |
2,446,549.1 ± 6.6 | |
83.4 ± 2.1 [1] | |
Semi-amplitude | 50.5 ± 1.6 |
Star | 16 Cygni B |
Physical characteristics | |
Mass | 2.38 ± 0.04 [1] MJ |
16 Cygni Bb or HD 186427 b is an extrasolar planet approximately 69 light-years (21 parsecs) away in the constellation of Cygnus. [2] The planet was discovered orbiting the Sun-like star 16 Cygni B, one of two solar-mass ( M☉) components of the triple star system 16 Cygni in 1996. [3] It orbits its star once every 799 days and was the first eccentric Jupiter and planet in a double star system to be discovered. The planet is abundant in lithium. [4]
In October 1996, the discovery of a planetary-mass companion to the star 16 Cygni B was announced, with a mass at least 1.68 times that of Jupiter ( MJ). At the time, it had the highest orbital eccentricity of any known planet. The discovery was made by measuring the star's radial velocity.[ citation needed]
As the inclination of the orbit cannot be directly measured and as no dynamic model of the system was then published, only a lower limit on the mass could then be determined. [1] [5]
Unlike the planets in the Solar System, the planet's orbit is highly elliptical, and its distance varies from 0.54 AU (50 million mi; 81 million km) at periastron to 2.8 AU (260 million mi; 420 million km) at apastron. [6] This high eccentricity may have been caused by tidal interactions in the binary star system, and the planet's orbit may vary chaotically between low and high-eccentricity states over a period of tens of millions of years. [7]
Preliminary astrometric measurements in 2001 suggested the orbit of 16 Cygni Bb may be highly inclined with respect to our line of sight (at around 173°). [8] This would mean the object's mass may be around 14 MJ; the dividing line between planets and brown dwarfs is at 13 MJ. However these measurements were later proved useful only for upper limits. [9]
Because the planet has only been detected indirectly by measurements of its parent star, properties such as its radius, composition, and temperature are unknown.[ citation needed]
A mathematical study in 2012 showed that a mass of about 2.4 MJ would be most stable in this system. [1] This would make the body a true planet.[ citation needed]
The planet's highly eccentric orbit means the planet would experience extreme seasonal effects. Despite this, simulations suggest that an Earth-like moon, should it have formed in an orbit so close to the parent star, would be able to support liquid water at its surface for part of the year. [10]
![]() 16 Cygni Bb rendered in Celestia | |
Discovery | |
---|---|
Discovered by | William D. Cochran, Artie P. Hatzes, R. Paul Butler, Geoff Marcy |
Discovery site | United States |
Discovery date | 22 October 1996 |
Radial velocity | |
Orbital characteristics | |
1.681 ± 0.097 AU (251,500,000 ± 14,500,000 km) | |
Eccentricity | 0.689 ± 0.011 [1] |
798.5 ± 1.0 d | |
Inclination | 45 or 135 [1] |
2,446,549.1 ± 6.6 | |
83.4 ± 2.1 [1] | |
Semi-amplitude | 50.5 ± 1.6 |
Star | 16 Cygni B |
Physical characteristics | |
Mass | 2.38 ± 0.04 [1] MJ |
16 Cygni Bb or HD 186427 b is an extrasolar planet approximately 69 light-years (21 parsecs) away in the constellation of Cygnus. [2] The planet was discovered orbiting the Sun-like star 16 Cygni B, one of two solar-mass ( M☉) components of the triple star system 16 Cygni in 1996. [3] It orbits its star once every 799 days and was the first eccentric Jupiter and planet in a double star system to be discovered. The planet is abundant in lithium. [4]
In October 1996, the discovery of a planetary-mass companion to the star 16 Cygni B was announced, with a mass at least 1.68 times that of Jupiter ( MJ). At the time, it had the highest orbital eccentricity of any known planet. The discovery was made by measuring the star's radial velocity.[ citation needed]
As the inclination of the orbit cannot be directly measured and as no dynamic model of the system was then published, only a lower limit on the mass could then be determined. [1] [5]
Unlike the planets in the Solar System, the planet's orbit is highly elliptical, and its distance varies from 0.54 AU (50 million mi; 81 million km) at periastron to 2.8 AU (260 million mi; 420 million km) at apastron. [6] This high eccentricity may have been caused by tidal interactions in the binary star system, and the planet's orbit may vary chaotically between low and high-eccentricity states over a period of tens of millions of years. [7]
Preliminary astrometric measurements in 2001 suggested the orbit of 16 Cygni Bb may be highly inclined with respect to our line of sight (at around 173°). [8] This would mean the object's mass may be around 14 MJ; the dividing line between planets and brown dwarfs is at 13 MJ. However these measurements were later proved useful only for upper limits. [9]
Because the planet has only been detected indirectly by measurements of its parent star, properties such as its radius, composition, and temperature are unknown.[ citation needed]
A mathematical study in 2012 showed that a mass of about 2.4 MJ would be most stable in this system. [1] This would make the body a true planet.[ citation needed]
The planet's highly eccentric orbit means the planet would experience extreme seasonal effects. Despite this, simulations suggest that an Earth-like moon, should it have formed in an orbit so close to the parent star, would be able to support liquid water at its surface for part of the year. [10]