16 Cygni
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Cygnus |
| 16 Cygni A | |
| Right ascension | 19h 41m 48.9535s |
| Declination | +50° 31′ 30.217″ |
| Apparent magnitude (V) | 5.96 |
| 16 Cygni B | |
| Right ascension | 19h 41m 51.9720s |
| Declination | +50° 31′ 03.083″ |
| Apparent magnitude (V) | 6.20 |
| Characteristics | |
| Spectral type | G1.5Vb / G2.5Vb / M?V |
| U−B color index | 0.19 / 0.20 |
| B−V color index | 0.64 / 0.66 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | -25.6 km/s |
| Proper motion (μ) | RA: -147.75 mas/yr Dec.: -158.85 mas/yr |
| Parallax (π) | 46.25 ± 0.50 mas |
| Distance | 70.5 ly (21.6 pc) |
| Absolute magnitude (MV) | 4.29 / 4.53 |
| Details | |
| 16 Cyg A | |
| Mass | 1.02 M☉ |
| Radius | 1.7 R☉ |
| Luminosity | 1.6 L☉ |
| Temperature | 5,803 ± 3.1[1] K |
| Metallicity | 114%Sun |
| Rotation | 26.9 |
| Age | 10.4 Gyr |
| 16 Cyg B | |
| Mass | 0.97 M☉ |
| Radius | 1.2 R☉ |
| Luminosity | 1.3 L☉ |
| Temperature | 5,752 ± 3.5[1] K |
| Metallicity | 123% Sun |
| Rotation | 29.1 |
| Age | 9.9 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Database references | |
| SIMBAD | data |
| Extrasolar Planets Encyclopaedia |
data |
16 Cygni or 16 Cyg is a triple star system approximately 70 light-years away from Earth in the constellation of Cygnus. It consists of two Sun-like yellow dwarf stars, 16 Cygni A and 16 Cygni B, together with a red dwarf, 16 Cygni C. In 1996 an extrasolar planet was discovered in an eccentric orbit around 16 Cygni B.
Contents |
[edit] Distance
The parallax of the two brightest stars were measured as part of the Hipparcos astrometry mission. This yielded a parallax of 46.25 milliarcseconds for 16 Cygni A[2] and 46.70 milliarcseconds for 16 Cygni B.[3] Since the two components are associated, it is reasonable to assume they lie at the same distance, so the different parallaxes are a result of experimental error (indeed, when the associated parallax errors are taken into account, the ranges of the parallaxes overlap). Using the parallax of the A component, the distance is 21.6 parsecs. The parallax of the B component corresponds to a distance of 21.4 parsecs.
[edit] Stellar components
16 Cygni is a hierarchal triple system. Stars A and C form a close binary with a projected separation of 73 AU.[4] The orbital elements of the A-C binary are currently unknown. At a distance of 860 AU from A is a third component designated 16 Cygni B. The orbit of B relative to the A-C pair was determined in 1999 and not updated since (as of June 2007): plausible orbits range in period from 18,200 to 1.3 million years, with a semimajor axis ranging from 877 to 15,180 AU. In addition B orbits between 100 and 160 degrees inclination, that is against the A-C pole such that 90 degrees would be ecliptical.[5]
Both 16 Cygni A and 16 Cygni B are yellow dwarf stars like our Sun. According to data from the Geneva-Copenhagen survey, both stars have masses similar to the Sun.[6][7] Age estimates for the two stars vary slightly, but 16 Cygni is likely to be much older than our solar system, at around 10,000 million years old. 16 Cygni C is much fainter than either of these stars, and may be a red dwarf.[4]
[edit] Planetary system
In 1996 an extrasolar planet in an eccentric orbit was announced around the star 16 Cygni B.[8] The planet's orbit takes 798.5 days to complete, with a semimajor axis of 1.68 AU.[9] Like the majority of known extrasolar planets, 16 Cygni Bb was detected by measuring the radial velocity of its parent star, which only gives a lower limit on the mass: in this case, about 1.68 times that of Jupiter. "For the 16 Cyg B system, only particles inside of about 0.3 AU remained stable [within a million years of formation], leaving open the possibility of short-period planets". For them, observation rules out any such planet of over a Neptune mass.[10]
There was a METI message sent to the 16 Cygni system. It was transmitted from Eurasia's largest radar – 70-meter (230-foot) Eupatoria Planetary Radar. The message was named Cosmic Call 1, it was sent on May 24, 1999, and it will arrive at 16 Cygni in November 2069.[11]
The 16 Cygni system is within the field of view of the now-operational Kepler Mission planet-hunter spacecraft.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | ≥1.68 ± 0.15 MJ | 1.681 ± 0.097 | 798.5 ± 1.0 | 0.681 ± 0.017 |
[edit] See also
[edit] References
- ^ a b Kovtyukh et al.; Soubiran, C.; Belik, S. I.; Gorlova, N. I. (2003). "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios". Astronomy and Astrophysics 411 (3): 559–564. arXiv:astro-ph/0308429. Bibcode 2003A&A...411..559K. doi:10.1051/0004-6361:20031378. http://www.aanda.org/articles/aa/full/2003/46/aa3944/aa3944.html.
- ^ "HIP 96895". The Hipparcos and Tycho Catalogues. ESA. 1997. http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HIP%2096895. Retrieved 27 June 2006.
- ^ "HIP 96901". The Hipparcos and Tycho Catalogues. ESA. 1997. http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HIP%2096901. Retrieved 27 June 2006.
- ^ a b Raghavan et al.; Henry, Todd J.; Mason, Brian D.; Subasavage, John P.; Jao, Wei‐Chun; Beaulieu, Thom D.; Hambly, Nigel C. (2006). "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems". The Astrophysical Journal 646 (1): 523–542. arXiv:astro-ph/0603836. Bibcode 2006ApJ...646..523R. doi:10.1086/504823. http://www.iop.org/EJ/article/0004-637X/646/1/523/64035.html.
- ^ Hauser, H., Marcy, G. (1999). "The Orbit of 16 Cygni AB". Publications of the Astronomical Society of the Pacific 111 (757): 321–334. Bibcode 1999PASP..111..321H. doi:10.1086/316328. http://www.journals.uchicago.edu/doi/full/10.1086/316328.
- ^ Holmberg et al. (2007). "Record 13627". Geneva-Copenhagen Survey of Solar neighbourhood. http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/117A/newcat&recno=13627. Retrieved 19 November 2008.
- ^ Holmberg et al. (2007). "Record 13631". Geneva-Copenhagen Survey of Solar neighbourhood. http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/117A/newcat&recno=13631. Retrieved 19 November 2008.
- ^ Cochran et al.; Hatzes, Artie P.; Butler, R. Paul; Marcy, Geoffrey W. (1997). "The Discovery of a Planetary Companion to 16 Cygni B". The Astrophysical Journal 483 (1): 457–463. arXiv:astro-ph/9611230. Bibcode 1997ApJ...483..457C. doi:10.1086/304245. http://www.iop.org/EJ/article/0004-637X/483/1/457/35587.html.
- ^ a b Butler et al.; Wright, J. T.; Marcy, G. W.; Fischer, D. A.; Vogt, S. S.; Tinney, C. G.; Jones, H. R. A.; Carter, B. D. et al (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode 2006ApJ...646..505B. doi:10.1086/504701. http://www.iop.org/EJ/article/0004-637X/646/1/505/64046.html.
- ^ Wittenmyer et al.; Endl, Michael; Cochran, William D.; Levison, Harold F. (2007). "Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems". The Astronomical Journal 134 (3): 1276–1284. Bibcode 2007AJ....134.1276W. doi:10.1086/520880. http://www.iop.org/EJ/article/1538-3881/134/3/1276/205882.html.
- ^ (Russian) http://www.cplire.ru/rus/ra&sr/VAK-2004.html
- Matthew Holman, Jihad Touma & Scott Tremaine (1997). "Chaotic variations in the eccentricity of the planet orbiting 16 Cygni B". Nature 386 (6622): 254–256. Bibcode 1997Natur.386..254H. doi:10.1038/386254a0. http://www.nature.com/nature/journal/v386/n6622/abs/386254a0.html.
[edit] External links
- Jean Schneider (2011). "Notes for star 16 Cyg B". Extrasolar Planets Encyclopaedia. http://exoplanet.eu/star.php?st=16+Cyg+B. Retrieved 30 September 2011.
- "16 Cygni 2?". SolStation. http://www.solstation.com/stars2/16cygni2.htm. Retrieved 2008-06-24.
- "16 Cygni B". Extrasolar Visions. http://www.extrasolar.net/startour.asp?StarCatId=&StarId=6. Retrieved 2008-06-24.
- "16 Cygni-B". University of Illinois at Urbana-Champaign. The Planet Project. http://www.astro.uiuc.edu/~kaler/sow/16cyg.html. Retrieved 2008-06-24.
- "16 Cyg B". Exoplanets. Archived from the original on 2009-05-06. http://media4.obspm.fr/exoplanets/base/etoile.php?nom=16+Cyg+B. Retrieved 2009-05-03.
- 16 Cygni on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
Coordinates: 
19h 41m 51.9720s, +50° 31′ 03.083″
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