16 Cygni
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The two stars of 16 Cygni
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A triple star system in the constellation Cygnus
consisting of two reasonably Sun-like stars
(both yellow dwarfs) and a red dwarf. One
of the Sun-like components (16 Cygni B) has been found to have a planet
(16 Cygni Bb) with a mass about 1½ times that of Jupiter
in a highly elongated orbit. The distance
of the planet from 16 Cygni B varies between less than the Venus-Sun
distance and more than the Mars-Sun distance.
The two brighter stars in the 16 Cyg system form a visual binary and are
separated by about 860 AU with an orbital period of at least 18,000 years.
16 Cyg A is very similar to the Sun; 16 Cyg B is slightly smaller and dimmer.
The 16 Cygni system, which is much older than our own solar system (with
an age of about 10 billion years), is among those that will be investigated
by the Kepler mission.
| Stars: 16 Cyg A and 16 Cyg B |
| distance |
69.8 light-years (21.42 parsecs) |
| spectral type |
G1.5V (A); G2.5V (B) |
| apparent magnitude |
5.96 (A); 6.20 (B) |
| metallicity |
0.09 (B) |
| mass |
1.01 Msun (B) |
| position |
R.A. 19h 41m 48.9s, Dec. 50° 31' 30.2" (A)
R.A. 19h 41m 52.0s, Dec. 50° 31' 3.1" (B) |
| other designations |
Gl 765.1A, BD +50 2847, HD 186408, HIP 96895 (A)
Gl 765.1B, BD +50 2848, HD 186427, HIP 96901 (B) |
| Planet: 16 Cyg B b |
| mass (Jupiter=1) |
1.68 |
| semimajor axis |
1.67 AU (251 million km, 155 million miles) |
| orbital period |
798.9 days |
| eccentricity |
0.67 |
| discovery |
1997, Marcy et al, California Carnegie Planet Search |
| method of discovery |
radial velocity |
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Orbit of 16 Cyg Bb around 16 Cyg
B (HD 186427) |
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Location of 16 Cygni
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References
- Cochran W., Hatzes A., Butler P., and Marcy G. "The discovery of a
planetary companion to 16 Cyg B," Astrophysical Journal, 483,
457 (1997).
- Hauser, H., and Marcy, G. "The Orbit of 16 Cygni AB," Publications
of the Astronomical Society of the Pacific, 111, 321 (1999).
- Laws C., and Gonzalez, G. "A Differential Spectroscopic Analysis of
16 Cygni A and B," Astrophysical Journal, 553, 405 (2001).
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