61 Cygni

61 Cygni
Observation data Epoch J2000.0 Equinox J2000.0
Expanded view of the star field around 61 Cygni. This system is located at the end of the arrow above.
Constellation	Cygnus
61 Cygni A
Right ascension	21^h 06^m 53.9434^s^[1]
Declination	+38° 44′ 57.898″^[1]
Apparent magnitude (V)	5.21^[1]
61 Cygni B
Right ascension	21^h 06^m 55.2648^s^[2]
Declination	+38° 44′ 31.400″^[2]
Apparent magnitude (V)	6.03^[2]
Characteristics
Spectral type	K5V^[1] / K7V^[2]
U−B color index	+1.155 / +1.242^[3]
B−V color index	+1.139 / +1.320^[3]
Variable type	A: BY Draconis^[1] B: Flare star^[2]
Astrometry

Radial velocity (R_v)	-64.3^[1]/-63.5^[2] km/s
Proper motion (μ)	RA: 4156.93^[1]/ 4109.17^[2] mas/yr Dec.: 3259.39^[1]/ 3144.17^[2] mas/yr
Parallax (π)	287.18 ± 1.51^[1] mas
Distance	11.36 ± 0.06 ly (3.48 ± 0.02 pc)
Absolute magnitude (M_V)	7.48/8.33

Details
61 Cygni A
Mass	0.70^[4] M_☉
Radius	0.665 ± 0.005^[5] R_☉
Surface gravity (log g)	4.40^[6]
Luminosity	0.215 L_☉
Temperature	4,526 ± 66^[7] K
Metallicity	[Fe/H] = -0.20^[6]
Rotation	35.37 d^[8]
61 Cygni B
Mass	0.63^[4] M_☉
Radius	0.595 ± 0.008^[5] R_☉
Surface gravity (log g)	4.20^[6]
Luminosity	0.15 L_☉
Temperature	4,077 ± 59^[7] K
Metallicity	[Fe/H] = -0.27^[6]
Rotation	37.84 d^[8]
Orbit^[9]
Companion	61 Cygni B
Period (P)	678 ± 34 yr
Semimajor axis (a)	24.272 ± 0.592"
Eccentricity (e)	0.49 ± 0.03
Inclination (i)	51 ± 2°
Longitude of the node (Ω)	178 ± 2°
Periastron epoch (T)	1709 ± 16
Argument of periastron (ω) (secondary)	149 ± 6°
Other designations
61 Cyg A/B GJ 820 A/B, Struve 2758 A/B, ADS 14636 A/B, V1803 Cyg A/B, GCTP 5077.00 A/B ^[10] 61 Cyg A V1803 Cyg, HD 201091, HIP 104214, HR 8085, BD+38°4343, LHS 62 ^[1] 61 Cyg B HD 201092, HIP 104217, HR 8086, BD+38°4344, LHS 63 ^[2]

61 Cygni,^{[note 1]} sometimes called Bessel's Star^[11] or Piazzi's Flying Star,^[12] is a binary star system in the constellation Cygnus. It consists of a pair of K-type dwarf stars that orbit each other in a period of about 659 years, forming a visual binary. At fifth and sixth apparent magnitudes, they are among the least conspicuous stars visible in the night sky to an observer without an optical instrument.

61 Cygni first attracted the attention of astronomers because of its large proper motion. In 1838, Friedrich Wilhelm Bessel measured its distance from Earth at about 10.4 light years, very close to the actual value of about 11.4 light years; this was the first distance estimate for any star other than the Sun,^[13] and first star to have its stellar parallax measured. Over the course of the twentieth century, several different astronomers reported detections of a massive planet orbiting one of the two stars, but recent high-precision radial velocity observations have shown that all such claims were erroneous.^[14]^[15]^[16] To date, no planets have been confirmed in this system and all of the past claims are now considered spurious.

1 Observation history
2 Properties
3 Claims of a planetary system
- 3.1 Refining planetary boundaries
4 See also
5 Notes
6 References
7 External links

Observation history

The large proper motion of 61 Cygni was first demonstrated by Giuseppe Piazzi in 1804, who christened it the "Flying Star".^[12] Piazzi's result, however, received little attention at the time due to the relatively short time span of his observations—a mere 10 years. It would take a publication by Friedrich Wilhelm Bessel in 1812 to bring this star to the widespread attention of astronomers.^[17]

Friedrich Georg Wilhelm von Struve first argued for its status as a binary in 1830. For many years thereafter, however, some uncertainty remained as to whether this pair was a mere juxtaposition of stars or a gravitationally bound system.^[18]

The system's large proper motion, the largest known for any star at the time, made 61 Cygni a candidate for the determination of its distance by the method of parallax when the quality of astronomical observations first made this possible. The system therefore has the distinction of being the first star (excluding the Sun) to have its distance from Earth measured. This was accomplished in 1838 by Bessel, who arrived at a parallax of 313.6 mas, close to the currently accepted value of 287.18 mas (yielding 11.36 light years).^[19]

Only a few years later, however, Groombridge 1830 was discovered to have a larger proper motion. 61 Cygni retains the distinction of having the largest proper motion of any star visible to the unaided eye (although Groombridge 1830 at magnitude 6.4 can be seen with the naked eye under exceptionally dark skies). 61 Cygni has the seventh highest proper motion of all stellar systems listed in the Hipparcos Catalogue.^[20]

By 1911, Bessel's parallax of 0.3136 had only slightly improved to 0.310, and observations at Yerkes Observatory had measured its radial velocity as 62 km/s^[21] which together with its proper motion—transverse to our line of sight—of around 79 km/s yielded a space velocity of about 100 km/s towards a point about 12 degrees west of Orion's belt.^{[note 2]}^{[note 3]}

In 1911, Benjamin Boss published data indicating that the 61 Cygni system was a member of a comoving group of stars.^[21] This group was later expanded to include 26 potential members. Possible members include Beta Columbae, Pi Mensae, 14 Tauri and 68 Virginis. The typical space velocities of this group of stars is 105–114 km/s relative to the Sun.^[22]

Because of their wide angular separation (and correspondingly slow orbital motion), it was initially unclear whether the two stars in the 61 Cygni system were physically connected. The respective parallax measurements of 0.360″ and 0.288″ gave a separation of more than two light years.^[23] However, by 1917 refined measured parallax differences demonstrated that the separation was significantly less.^[24] The binary nature of this system was clear by 1934, and orbital elements were published.^[25]

An observer using 7×50 binoculars can find 61 Cygni two binocular fields south-east of the bright star Deneb. The angular separation of the two stars is slightly greater than the angular size of Saturn (16–20″).^[26] So, under ideal viewing conditions, the binary system can be resolved by a telescope with a 6 mm aperture.^{[note 4]} This is well within the capability of a typical pair of binoculars.

Properties

Although it appears to be a single star to the naked eye, 61 Cygni is in fact a widely separated binary system, composed of two K class (orange) main sequence stars, 61 Cygni A and 61 Cygni B. The brighter star 61 Cygni A is of apparent magnitude 5.2, the fainter 61 Cygni B is 6.1. Both appear to be old-disk stars,^[27] with an estimated age that is older than the Sun. The system has a net space velocity of 108 km/s^[28] relative to the Sun, which results in the high proper motion across the sky.^[29] At a distance of just over 11 light years, it is one of the nearest star systems to the Earth.^[4] This system will make its closest approach at about 20,000 CE, when the separation from the Sun will be about 9 light years.^[28]

A size comparison between the Sun (left), 61 Cygni A (bottom) and 61 Cygni B (upper right).

The two orbit their common barycenter in a period of 659 years, with a mean separation of about 84 A.U.—84 times the separation between the Earth and the Sun. The relatively large orbital eccentricity of 0.48 means that the two stars are separated by about 44 A.U. at periapsis and 124 A.U. at apoapsis.^{[note 5]} The leisurely orbit of the pair has made it difficult to pin down their respective masses, and the accuracy of these values remain somewhat controversial. In the future this issue may be resolved through the use of asteroseismology.^[5]

Component A has about 11% more mass than component B.^[4] It has an activity cycle that is much more pronounced than the solar sunspot cycle. This is a complex activity cycle that varies with a period of about 7.5±1.7 years.^[30] (An earlier estimate gave a period of 7.3 years.)^[31] The combination of starspot activity combined with rotation and chromospheric activity is characteristic of a BY Draconis variable. Because of differential rotation, this star's surface rotation period varies by latitude from 27 to 45 days, with an average period of 35 days.^[8]

The outflow of the stellar wind from component A produces a bubble within the local interstellar cloud. Along the direction of the star's motion within the Milky Way, this extends out to a distance of only 30 AU, or roughly the orbital distance of Neptune from the Sun. This is lower than the separation between the two components of 61 Cygni, and so the two most likely do not share a common atmosphere. The compactness of the astrosphere is likely due to the low mass outflow and the relatively high velocity through the local medium.^[32]

Component B displays a more chaotic pattern of variability than A, with significant short-term flares. There is an 11.7 year periodicity to the overall activity cycle of B.^[31] Both stars exhibit stellar flare activity, but the chromosphere of component B is 25% more active than for component A.^[33] As a result of differential rotation, the period of rotation varies by latitude from 32 to 47 days, with an average period of 38 days.^[8]

There is some disagreement over the evolutionary age of this system. Kinematic data gives an age estimate of about 10 Gyr.^[29] Gyrochronology, or the age determination of a star based on its rotation and color, results in an average age of 2.0 ± 0.2 Gyr. The ages based on chromospheric activity for A and B are 2.36 Gyr and 3.75 Gyr, respectively. Finally the age estimates using the isochrone method, which involve fitting the stars to evolutionary models, yield upper limits of 0.44 Gyr and 0.68 Gyr.^[34] However, a 2008 evolutionary model using the CESAM2k code from the Côte d'Azur Observatory gives an age estimate of 6.0 ± 1.0 Gyr for the pair.^[5]

Claims of a planetary system

On several occasions, it has been claimed that 61 Cygni has unseen low-mass companions, planets or a brown dwarf. Kaj Strand of the Sproul Observatory, under the direction of Peter van de Kamp, made the first such claim in 1942 using observations to detect tiny but systematic variations in the orbital motions of 61 Cygni A and B. These perturbations suggested that a third body was orbiting 61 Cygni A.^[35] In 1957, he narrowed his uncertainties, claiming that the object had a mass eight times the mass of Jupiter, a calculated orbital period of 4.8 years, and a semi-major axis of 2.4 A.U.^[36] In 1977, Soviet astronomers at the Pulkovo Observatory near Saint Petersburg suggested that the system included three planets: two giant planets with six and twelve Jupiter masses around 61 Cyg A, and one giant planet with seven Jupiter masses around 61 Cygni B.^[37] In 1978, Wulff Dieter Heintz of the Sproul Observatory proved that these claims, as well as the claims for unseen companions around many other stars, were spurious, having failed to detect any evidence of such motion down to six percent of the Sun's mass—equivalent to about 60 times the mass of Jupiter.^[38]

Refining planetary boundaries

Since no certain planetary object has been detected around either star so far, McDonald Observatory team has set limits to the presence of one or more planets around 61 Cygni A and 61 Cygni B with masses between 0.07 and 2.4 Jupiter masses and average separations spanning between 0.05 and 5.2 A.U.^[39]

Because of the proximity of this system to the Sun, it is a frequent target of interest for astronomers. Both stars were selected by NASA as "Tier 1" targets for the proposed optical Space Interferometry Mission.^[40] This mission is potentially capable of detecting planets with as little as 3 times the mass of the Earth at an orbital distance of 2 A.U. from the star. Measurements of this system have detected an excess of far infrared radiation, beyond what is emitted by the stars. Such an excess is sometimes associated with a disk of dust, but in this case it lies sufficiently close to one or both of the stars that it has not yet been resolved with a telescope.^[41]

Notes

↑ Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb.
↑ The space velocity calculated from 1911 data: parallax 310 mas yields 10.5 light years; total proper motion= 5.205 arcsec/year (average by mass) or 79.4 km/s; and radial velocity = -62 km/s.
↑ This yields a 1911 space velocity of $\begin{smallmatrix}\sqrt{79.4^2\ +\ 62^2}\ =\ 100\end{smallmatrix}$ km/s. Compare with more accurate 1953, 1997 data: parallax 287.18 yields 11.36 ly and so an increased proper motion velocity of 87 km/s; radial velocity -64 km/s yields a net space velocity of $\begin{smallmatrix}\sqrt{87^2\ +\ 64^2}\ =\ 106\end{smallmatrix}$ km/s.
↑ Per the Rayleigh criterion: $\begin{smallmatrix}\alpha_R\ =\ \frac{138}{D}\end{smallmatrix}$ mm.
↑ At periapsis: $\begin{smallmatrix}r_{per}\ =\ (1\ -\ e)\cdot a\ \approx\ 44\end{smallmatrix}$ A.U.
At apoapsis: $\begin{smallmatrix}r_{ap}\ =\ (1\ +\ e)\cdot a\ \approx\ 124\end{smallmatrix}$ A.U.

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 ^1.7 ^1.8 ^1.9 "SIMBAD Query Result: V* V1803 Cyg -- Variable of BY Dra type". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=HD+201091. Retrieved 2007-07-15. (61 Cygni A)
↑ ^2.0 ^2.1 ^2.2 ^2.3 ^2.4 ^2.5 ^2.6 ^2.7 ^2.8 "SIMBAD Query Result: NSV 13546 -- Flare Star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=HD+201092. Retrieved 2007-07-15. (61 Cygni B)
↑ ^3.0 ^3.1 Blanco, C.; Marilli, E.; Catalano, S. (1979). "Photoelectric observations of stars with variable H and K emission components. III". Astronomy and Astrophysics Supplement Series 36: 297–306. http://adsabs.harvard.edu/abs/1979A%26AS...36..297B. Retrieved 2007-02-04.
↑ ^4.0 ^4.1 ^4.2 ^4.3 Staff (June 8, 2007). "List of the Nearest 100 Stellar Systems". Research Consortium on Nearby Stars, Georgia State University. http://joy.chara.gsu.edu/RECONS/. Retrieved 2007-07-15.
↑ ^5.0 ^5.1 ^5.2 ^5.3 Kervella, P.; Mérand, A.; Pichon, B.; Thévenin, F.; Heiter, U.; Bigot, L.; Ten Brummelaar, T. A.; McAlister, H. A.; Ridgway, S. T.; Turner, N.; Sturmann, J.; Sturmann, L.; Goldfinger, P. J.; Farrington, C. (September 2008). "The radii of the nearby K5V and K7V stars 61 Cygni A & B. CHARA/FLUOR interferometry and CESAM2k modeling". Astronomy and Astrophysics 488 (2): 667–674. doi:10.1051/0004-6361:200810080.
↑ ^6.0 ^6.1 ^6.2 ^6.3 Luck, R. Earle; Heiter, Ulrike (2005). "Stars within 15 Parsecs: Abundances for a Northern Sample". The Astronomical Journal 129 (2): 1063–1083. doi:10.1086/427250. http://adsabs.harvard.edu/abs/2005AJ....129.1063L. Retrieved 2007-07-17.
↑ ^7.0 ^7.1 van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal 694 (2): 1085–1098. doi:10.1088/0004-637X/694/2/1085.
↑ ^8.0 ^8.1 ^8.2 ^8.3 Böhm-Vitense, Erika (March 2007). "Chromospheric Activity in G and K Main-Sequence Stars, and What It Tells Us about Stellar Dynamos". The Astrophysical Journal 657 (1): 486–493. doi:10.1086/510482.
↑ Hartkopf, W. I.; Brian D. Mason, B. D.. "Sixth Catalog of Orbits of Visual Binary Stars". U.S. Naval Observatory. http://ad.usno.navy.mil/wds/orb6.html. Retrieved 2008-07-12.
↑ "SIMBAD Query Result: ADS 14636 AB -- Double or multiple star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=61+cygni&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id. Retrieved 2009-04-01. (61 Cygni)
↑ Pannekoek, Anton (1989). A History of Astronomy. Courier Dover Publications. pp. 343. ISBN 0486659941.
↑ ^12.0 ^12.1 Hirshfeld, Alan (2001). Parallax: The Race to Measure the Cosmos. Macmillan. ISBN 0716737116.
↑ Frommert, Hartmut; Kronberg, Christine. "Friedrich Wilhelm Bessel". Students for the Exploration and Development of Space. http://www.seds.org/MESSIER/xtra/Bios/bessel.html. Retrieved 2009-04-03.
↑ Walker, G. A. H.; Walker, A. R.; Irwin, A. W.; Larson, A. M.; Yang, S. L. S.; Richardson, D. C (1995). "A search for Jupiter-mass companions to nearby stars". Icarus 116 (2): 359–375. doi:10.1006/icar.1995.1130.
↑ Cumming, A.; Marcy, G. W.; Butler, R. P. (1999). "The Lick planet search: detectability and mass thresholds". Astrophysical Journal 526: 890–915. doi:10.1086/308020.
↑ Wittenmyer, R. A.; Endl, M.; Cochran, W.D.; Hatzes , A.; Walker, G. A. H.; Yang, S. L. S.; Paulson, D. B. (2006). "Detection limits from the McDonald Observatory planet search program". Astronomical Journal 132: 177–188. doi:10.1086/504942.
↑ Fodera-Serio, G. (1990). "Giuseppe Piazzi and the Discovery of the Proper Motion of 61-Cygni". Journal of the History of Astronomy 21 (3): 275. http://adsabs.harvard.edu/abs/1990JHA....21..275F. Retrieved 2007-07-14.
↑ Davis, Merhan S. (1898). "Remarks regarding the parallaxes of 61 Cygni and the probable physical connection of these two stars.". Astrophysical Journal 8: 246–247. doi:10.1086/140527. http://adsabs.harvard.edu/abs/1898ApJ.....8..246D. Retrieved 2007-07-15.
↑ Bessel, F. W. (1839). "Bestimmung der Entfernung des 61sten Sterns des Schwans. Von Herrn Geheimen - Rath und Ritter Bessel" (in German). Astronomische Nachrichten 16: 65. doi:10.1002/asna.18390160502. http://adsabs.harvard.edu/abs/1839AN.....16...65B. Retrieved 2007-07-17. "(page 92) Ich bin daher der Meinung, daß nur die jährliche Parallaxe = 0"3136 als das Resultat der bisherigen Beobachtungen zu betrachten ist". A parallax of 313.6 mas yields a distance of 10.4 light years
↑ Staff (May 4, 2007). "High Proper Motion Stars: Interesting Areas to View". ESA. http://www.rssd.esa.int/index.php?project=HIPPARCOS&page=areas. Retrieved 2007-07-16.
↑ ^21.0 ^21.1 Boss, Benjamin (1911). "Community of motion among several stars of large proper-motion". Astronomical Journal 27 (629): 33–37. doi:10.1086/103931. http://adsabs.harvard.edu/abs/1911AJ.....27...33B. Retrieved 2007-07-17.
↑ Eggen, O. J. (1959). "White dwarf members of the 61 Cygni group". The Observatory 79: 135–39. http://adsabs.harvard.edu/abs/1959Obs....79..135E. Retrieved 2007-07-17. – Gives space velocity components of U=+94, V=-53 and W=-7 for HD 201091/2.
↑ Davis, H. S. (1898). "Remarks regarding the parallaxes of 61 Cygni and the probable physical connection of these two stars". Astrophysical Journal 61 (2): 246–47. doi:10.1086/140527. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1898ApJ.....8..246D. Retrieved 2007-09-11.
↑ Adams, W. S.; Joy, A. H. (1917). "The luminosities and parallaxes of five hundred stars". Astrophysical Journal 46: 313–39. doi:10.1086/142369. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1917ApJ....46..313A&db_key=AST&nosetcookie=1. Retrieved 2007-09-11. —See Table I, page 326
↑ Baize, P.; Joy, A. H. (1950). "Second catalogue d'orbites d'Etoiles Doubles visuelles" (in French). Journal des Observateurs 33: 1–31. doi:10.1086/142369. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1917ApJ....46..313A&db_key=AST&nosetcookie=1. Retrieved 2007-09-11. —on page 19, the authority is listed as Zagar (1934).
↑ Espenak, Fred (July 25, 1996). "Twelve Year Planetary Ephemeris: 1995 - 2006". NASA. http://sunearth.gsfc.nasa.gov/eclipse/TYPE/preface.html. Retrieved 2007-07-25.
↑ Gudel, M. (1992). "Radio and X-ray emission from main-sequence K stars". Astronomy and Astrophysics 264 (2): L31–L34. http://adsabs.harvard.edu/abs/1992A&A...264L..31G. Retrieved 2007-07-16.
↑ ^28.0 ^28.1 Anonymous (March 18, 2006). "Long-Term Stellar Motions, part 2: Shortcuts". The Astronomy Nexus. http://www.astronexus.com/node/41. Retrieved 2007-10-21.
↑ ^29.0 ^29.1 Affer, L.; Micela, G.; Morel, T.; Sanz-Forcada, J.; Favata, F. (2005). "Spectroscopic determination of photospheric parameters and chemical abundances of 6 K-type stars". Astronomy and Astrophysics 433 (2): 647–658. doi:10.1051/0004-6361:20041308. http://adsabs.harvard.edu/abs/2005A&A...433..647A. Retrieved 2007-07-25.
↑ Frick, P.; Baliunas, S. L.; Galyagin, D.; Sokoloff, D.; Soon, W. (1997). "Wavelet Analysis of Chromospheric Activity". Astrophysical Journal 483: 426–434. doi:10.1086/304206. http://adsabs.harvard.edu/abs/1997ApJ...483..426F. Retrieved 2007-07-15.
↑ ^31.0 ^31.1 Hempelmann, A.; Schmitt, J. H. M. M.; Baliunas, S. L.; Donahue, R. A. (2003). "Evidence for coronal activity cycles on 61 Cygni A and B". Astronomy and Astrophysics 406: L39–L42. doi:10.1051/0004-6361:20030882. http://adsabs.harvard.edu/abs/2003A&A...406L..39H. Retrieved 2007-07-15.
↑ Wood, Brian E.; Müller, Hans-Reinhard; Zank, Gary P.; Linsky, Jeffrey L. (July 2002). "Measured Mass-Loss Rates of Solar-like Stars as a Function of Age and Activity". The Astrophysical Journal 574 (1): 412–425. doi:10.1086/340797.
↑ Hempelmann, A.; Robrade, J.; Schmitt, J. H. M. M.; Favata, F.; Baliunas, S. L.; Hall, J. C. (2006). "Coronal activity cycles in 61 Cygni". Astronomy and Astrophysics 460 (1): 261–267. doi:10.1051/0004-6361:20065459. http://adsabs.harvard.edu/abs/2006A&A...460..261H. Retrieved 2007-07-16.
↑ Barnes, Sydney A. (November 2007). "Ages for Illustrative Field Stars Using Gyrochronology: Viability, Limitations, and Errors". The Astrophysical Journal 669 (2): 1167–1189. doi:10.1086/519295.
↑ Strand, K. Aa. (1943). "61 Cygni as a Triple System". Publications of the Astronomical Society of the Pacific 55 (322): 29–32. doi:10.1086/125484. http://adsabs.harvard.edu/abs/1943PASP...55...29S. Retrieved 2007-07-15.
↑ Strand, K. Aa. (1957). "The orbital motion of 61 Cygni.". The Astronomical Journal 62: 35. doi:10.1086/107588. http://adsabs.harvard.edu/abs/1957AJ.....62Q..35S. Retrieved 2007-07-15.
↑ Asimov, Isaac (1981). Extraterrestrial Civilizations. London: Pan Books Ltd. ISBN 0330262491.
↑ Heintz, W. D. (1978). "Reexamination of suspected unresolved binaries". The Astrophysical Journal 220: 931–934. doi:10.1086/155982. http://adsabs.harvard.edu/abs/1978ApJ...220..931H. Retrieved 2007-07-15.
↑ Wittenmeyer, R. A. et al. (May 2006). "Detection Limits from the McDonald Observatory Planet Search Program". The Astronomical Journal 132 (1): 177–188. doi:10.1086/504942. arXiv:astro-ph/0604171.
↑ "SIM Planet Search Tier 1 Target Stars". San Francisco State University. http://tauceti.sfsu.edu/~chris/SIM/t1.html. Retrieved 2007-07-23.
↑ Kuchner, Marc J.; Brown, Michael E.; Koresko, Chris D. (1998). "An 11.6 Micron Keck Search for Exo-Zodiacal Dust". The Publications of the Astronomical Society of the Pacific 110 (753): 1336–41. doi:10.1086/316267. http://adsabs.harvard.edu/cgi-bin/bib_query?1998PASP..110.1336K. Retrieved 2007-07-25.

External links

"61 Cygni 2". SolStation. http://www.solstation.com/stars/61cygni2.htm. Retrieved 2007-07-16.
Kaler, James B.. "61 Cygni". University of Illinois at Urbana-Champaign. http://www.astro.uiuc.edu/~kaler/sow/61cyg.html. Retrieved 2007-07-16.

Coordinates: 21^h 06^m 53.9434^s, +38° 44′ 57.898″

Nearest star systems

Star systems (including brown dwarf systems) within 30 light-years from Earth.

0 – 5 ly

G V (Yellow)	Solar System (1 star, 8 planets) • Alpha Centauri (3 stars: Alpha¹ Centauri • Alpha² Centauri • Proxima Centauri)

5 – 10 ly

A V (White)	Sirius (2 stars)

M V (Red dwarf)	Barnard's Star system (1 star) • Wolf 359 (1 star) • Lalande 21185 (1 star) • BL/UV Ceti (2 stars) • Ross 154 (1 star)

10 – 15 ly

F V (Yellow-white)	Procyon (2 stars)

G V (Yellow)	Tau Ceti (1 star)

K V (Orange)	Sadira (1 star, 2 planets: planet b • planet c) • 61 Cygni (2 stars) • Epsilon Indi (1 star, 2 brown dwarfs)

M V (Red dwarf)	Ross 248 (1 star) • Lacaille 9352 (1 star) • Ross 128 (1 star) • EZ Aquarii (3 stars) • Struve 2398 (2 stars) • Groombridge 34 (2 stars) • DX Cancri (1 star) • GJ 1061 (1 star) • YZ Ceti (1 star) • Luyten's Star system (1 star) • Teegarden's Star system (1 star) • SCR 1845-6357 (1 star, 1 brown dwarf) • Kapteyn's Star system (1 star) • Lacaille 8760 (1 star) • Kruger 60 (2 stars) • Ross 614 (2 stars) • Wolf 1061 (1 star) • Gliese 1 (1 star) • Wolf 424 (2 stars: Wolf 424 A • Wolf 424 B) • TZ Arietis (1 star) • Gliese 687 (1 star) • LHS 292 (1 star)‡ • Gliese 674 (1 star, 1 planet: planet b) • GJ 1245 (3 stars)

White
Dwarf

DZ	van Maanen's Star system (1 star)

Brown
Dwarf

M	DEN 1048-3956 (1 brown dwarf)

T/Y	UGPS 0722-05 (1 brown dwarf)‡

15 – 20 ly

A V (White)	Altair (1 star)

G V (Yellow)	Achird (2 stars) • e Eridani (1 star) • Delta Pavonis (1 star)

K V (Orange)	Groombridge 1618 (1 star) • Keid (3 stars) • 70 Ophiuchi (2 stars) • Alsafi (1 star) • 33G. Librae (3 stars, 1 brown dwarf) • 36 Ophiuchi (3 stars) • Gliese 783 (2 stars)

M V (Red dwarf)	GJ 1002 (1 star) • Gliese 876 (1 star, 4 planets: planet d • planet c • planet b • planet e) • LHS 288 (1 star) • Gliese 412 (2 stars) • AD Leonis (1 star) • Gliese 832 (1 star, 1 planet: planet b) • Gliese 682 (1 star) • EV Lacertae (1 star) • EI Cancri (2 stars) • GJ 3379 (1 star) • LHS 1723 (1 star) • Gliese 445 (1 star) • Wolf 498 (1 star) • LP 816-060 (1 star) • Gliese 251 (1 star) • Gliese 205 (1 star) • Gliese 229 (1 star, 1 brown dwarf) • Gliese 693 (1 star) • Gliese 752 (2 stars: Gliese 752 A • Gliese 752 B) • Ross 47 (1 star) • Gliese 754 (1 star) • BR Piscis (1 star) • Gliese 588 (1 star) • GJ 1005 (1 star) • YZ Canis Minoris (1 star)

White
Dwarf

DC	Stein 2051 (2 stars)

DQ	Gliese 440 (1 star)‡ • GJ 1221 (1 star)‡

Brown
Dwarf

M	LP 944-020 (1 brown dwarf) • 2MASS 1835+3259 (1 brown dwarf)

L	DEN 0255-4700 (1 brown dwarf)

T	DEN 0817-6155 (1 brown dwarf)‡ • 2MASS 0939-2448 (2 brown dwarfs) • 2MASS 0415-0935 (1 brown dwarf)

20 – 25 ly

G
(Yellow)

IV	Beta Hydri (1 star)

V	Xi Boötis (2 stars)

VI	Marfak-West (2 stars)

K V (Orange)	Gliese 338 (2 stars)‡ • Gliese 892 (1 star) • Gliese 667 (3 stars, 1 planet: planet Cb) • HR 753 (3 stars) • Gliese 33 (1 star) • 107 Piscium (1 star) • TW Piscis Austrini (1 star)‡

M V (Red dwarf)	QY Aurigae (2 stars)‡ • HN Librae (1 star)‡ • Gliese 784 (1 star) • Gliese 581 (1 star, 6 planets: planet e • planet b • planet c • planet g • planet d • planet f) • EQ Pegasi (2 stars) • LHS 2090 (1 star) • LHS 337 (1 star) • Gliese 661 (2 stars) • LHS 3003 (1 star) • G 180-060 (1 star) • Gliese 644 (5s) • GL Virginis (1 star) • Gliese 625 (1 star) • Gliese 408 (1 star) • Gliese 829 (2 stars) • G 41-14 (3 stars) • EE Leonis (1 star) • Gliese 299 (1 star) • Gliese 880 (2 stars) • LP 771-095 (3 stars) • GJ 1068 (1 star) • Gliese 809 (1 star) • Gliese 54 (2 stars) • GJ 1286 (1 star) • Gliese 393 (1 star) • GJ 3991 (1 star)‡ • GJ 4053 (1 star) • GJ 1230 (3 stars)‡ • GJ 4274 (1 star)‡ • GJ 4248 (1 star) • GJ 1224 (1 star)‡ • Gliese 109 (1 star)‡ • GJ 3378 (1 star)‡ • Gliese 514 (1 star)‡ • Gliese 480.1 (1 star)‡

White
Dwarf

DZ	Gliese 223.2 (1 star)

Brown
Dwarf

L	2MASS 1507-1627 (1 brown dwarf)

T	2MASS 0937+2931 (1 brown dwarf)‡ • SIMP J013656.5+093347 (1 brown dwarf)‡

25 – 30 ly

A V (White)	Fomalhaut (1 star, 1 planet: planet b)‡ • Vega (1 star)

F V (Yellow-white)	Tabit (1 star) • Batentaban Borealis (2 stars) • Zeta Tucanae (1 star) • Gamma Leporis (2 stars)

G
(Yellow)

IV	Mu Herculis (3 stars)

V	Alula Australis (3 stars, 1 brown dwarf) • Chara (1 star) • 61 Virginis (1 star, 3 planets: planet b • planet c • planet d) • Chi¹ Orionis (2 stars) • 41 G. Arae (2 stars) • Beta Comae Berenices (1 star)‡ • Kappa¹ Ceti (1 star)‡

VI	Groombridge 1830 (1 star)‡

K
(Orange)

IV	Rana (1 star)

V	Gliese 673 (1 star)‡ • Gliese 884 (1 star) • p Eridani (2 stars) • Gliese 250 (2 stars) • HR 1614 (1 star) • HR 7722 (1 star, 1 planet: planet b)

M V
(Red dwarf)

GJ 2005 (3 stars)‡ • GJ 1093 (1 star)‡ • Gliese 686 (1 star) • Gliese 701 (1 star) • Gliese 382 (1 star) • SIPS 1259-4336 (1 star) • GJ 3789 (1 star)‡ • Gliese 793 (1 star) • SSSPM J1138-7722 (1 star)‡ • Gliese 831 (2 stars) • Gliese 257 (2 stars) • Gliese 623 (2 stars) • GJ 4063 (1 star)‡ • GJ 1105 (1 star) • GJ 1289 (1 star) • Gliese 493.1 (1 star) • Gliese 48 (1 star) • Gliese 747 (2 stars) • Gliese 300 (1 star) • Gliese 486 (1 star) • GJ 1151 (1 star) • LP 655-48 (1 star)‡ • GJ 1227 (1 star) • SCR 1138-7721 (1 star) • Gl 232 (1 star) • SCR 0838-5855 (1 star)‡ • Gliese 438 (1 star) • GJ 3146 (1 star) • GJ 1154 (1 star) • GJ 1057 (1 star) • Gliese 618 (2 stars) • GJ 3076 (1 star)‡ • SCR 0640-0552 (1 star)‡ • Gliese 185 (2 stars) • Gliese 450 (1 star) • GJ 3517 (1 star) • Gliese 877 (1 star) • Gliese 745 (2 stars) • Gliese 867 (2 stars) • GJ 3454 (2 stars) • Gliese 791.2 (2 stars) • LDS 169 (2 stars)‡ • Gliese 849 (1 star, 1 planet: planet b) • GJ 1103 (2 stars) • GJ 1207 (1 star)‡ • Gliese 465 (1 star) • GJ 1277 (1 star) • SCR 0630-7643 (2 stars) • GJ 3128 (1 star) • GJ 3707 (1 star)‡ • GJ 3820 (1 star)‡ • GJ 4247 (1 star) • Gliese 357 (1 star) • Gliese 595 (1 star)‡ • GJ 4360 (1 star)‡ • Gliese 433 (1 star, 1 planet: planet b) • Gliese 424 (1 star) • GJ 3801 (1 star)‡ • GJ 2066 (1 star)‡ • GJ 3421 (2 stars)‡ • Gliese 317 (1 star, 1 planet: planet b)‡ • SCR 1826-6542 (1 star)‡

White
Dwarf

DA	GJ 2034 (2 stars)‡ • GJ 1087 (1 star) • Gliese 915 (1 star) • Gliese 318 (1 star)

DC	GJ 3667 (1 star)

DQ	Gliese 293 (1 star) • GJ 2012 (1 star)

DZ	Gliese 518 (1 star) • GJ 1276 (1 star) • Gliese 283 (2 stars)

Brown
Dwarf

L	SDSS J1416+13 (2 brown dwarfs)‡ • 2MASS 0036+1821 (1 brown dwarf)

T	2MASS 0727+1710 (1 brown dwarf)‡

In left column are stellar classes of primary members of star systems. ‡Distance error margin extends out of declared distance interval.

Nearest bright star systems

Star systems within 70 light-years from Earth with brightest member's absolute magnitude of +8.5 or brighter.

0 – 10 ly

A V (White)	Sirius (2s)

G V (Yellow)	Solar System (1s, 8p) • Alpha Centauri (3s: Alpha¹ Centauri • Alpha² Centauri • Proxima Centauri)

10 – 20 ly

A V (White)	Altair (1s)

F V (Yellow-white)	Procyon (2s)

G V (Yellow)	Tau Ceti (1s) • Achird (2s) • e Eridani (1s) • Delta Pavonis (1s)

K V (Orange)	Epsilon Eridani (1s, 2p: planet b • planet c) • 61 Cygni (2s) • Epsilon Indi (1s, 2bd) • Groombridge 1618 (1s) • Keid (3s) • 70 Ophiuchi (2s) • Alsafi (1s) • 33G. Librae (3s, 1bd) • 36 Ophiuchi (3s) • Gliese 783 (2s)

20 – 30 ly

A V (White)	Fomalhaut (1s, 1p: planet b) • Vega (1s)

F V (Yellow-white)	Tabit (1s) • Batentaban Borealis (2s) • Zeta Tucanae (1s) • Gamma Leporis (2s)

G
(Yellow)

IV	Beta Hydri (1s) • Mu Herculis (3s)

V	Xi Boötis (2s) • Alula Australis (3s, 1bd) • Chara (1s) • 61 Virginis (1s, 3p: planet b • planet c • planet d) • Chi¹ Orionis (2s) • 41 G. Arae (2s) • Beta Comae Berenices (1s)‡ • Kappa¹ Ceti (1s)‡

VI	Marfak-West (2s) • Groombridge 1830 (1s)‡

K
(Orange)

IV	Rana (1s)

V	Gliese 892 (1s) • Gliese 667 (3s, 1p: planet Cb) • HR 753 (3s) • Gliese 33 (1s) • 107 Piscium (1s) • TW Piscis Austrini (1s) • Gliese 673 (1s) • Gliese 884 (1s) • p Eridani (2s) • Gliese 250 (2s) • HR 1614 (1s) • HR 7722 (1s, 1p: planet b)

30 – 40 ly

Giant
star

K III

Pollux (1s, 1p: planet b) • Arcturus (1s)

A
(White)

IV	Scheddi (4s)

V	Denebola (1s)

F
(Yellow-
white)

IV	Rutilicus (2s)

V	Gamma Pavonis (1s)‡ • Zavijava (2s) • Ainalhai (1s) • Theta Persei (2s) • Zeta Doradus (1s) • Iota Pegasi (2s) • Porrima (2s) • Zeta Trianguli Australis (2s)

G
(Yellow)

IV	Muphrid (2s)

V	HR 4523 (2s) • 61 Ursae Majoris (1s) • Alpha Mensae (1s) • Iota Persei (1s) • Delta Trianguli (2s) • 11 Leonis Minoris (2s) • Lambda Serpentis (1s) • Zeta Reticuli (2s)

K V (Orange)	HR 4458 (2s) • Gliese 638 (1s) • 12 Ophiuchi (1s) • HR 511 (1s) • HR 5256 (1s) • HD 122064 (1s) • Gliese 453 (1s) • HR 857 (1s) • Gliese 688 (1s) • Gliese 653 (2s) • HR 9038 (2s) • HR 637 (2s, 1p: planet b) • HR 6806 (1s) • 54 Piscium (1s, 1bd, 1p: planet b) • Gliese 320 (1s) • Gliese 370 (1s) • Gliese 505 (2s) • Gliese 208 (1s) • Gliese 902 (1s) • Gliese 169 (1s) • HR 5553 (2s) • Gliese 773.6 (1s) • Gliese 542 (1s) • Gliese 414 (2s) • Gliese 798 (1s)‡ • HR 3384 (1s)‡ • HR 1925 (1s)‡

M V (Red dwarf)	Gliese 617 (2s) • Gliese 488 (1s)

40 – 50 ly

Giant
star

A III	Rasalhague (1s)

G III	Capella (4s)

A
(White)

IV	Alderamin (1s)

V	Talitha Borealis (4s)

F
(Yellow-
white)

IV	Beta Trianguli Australis (2s)‡ • Alhaud (3s)

V	36 Ursae Majoris (2s) • Upsilon Andromedae (2s, 4p: planet b • planet c • planet d • planet e) • 10 Tauri (2s) • Iota Piscium (1s) • Tau¹ Eridani (2s) • Dalim (2s) • Asellus Primus (2s) • 111 Tauri (2s) • Yue (1s) • Alchiba (1s) • Eta Leporis (1s) • Nu Phoenicis (1s) • 19 Draconis (2s)

G
(Yellow)

IV	Alshain (2s) • b Aquilae (3s)

V	85 Pegasi (3s)‡ • Rho¹ (55) Cancri (2s, 5p: planet e • planet b • planet c • planet f • planet d) • HR 483 (2s) • Al Hurr (2s) • HR 683 (1s) • i (44) Boötis (3s) • HR 6094 (2s, 1p: planet b) • HR 6998 (1s) • 58 Eridani (1s) • HR 8501 (2s) • 18 Scorpii (1s) • 47 Ursae Majoris (1s, 3p: planet b • planet c • planet d) • 26 Draconis (3s) • Pi¹ Ursae Majoris (1s) • Gliese 611 (2s) • 72 Herculis (1s) • Nu² Lupi (1s) • HR 7898 (1s) • Psi Serpentis (2s) • HR 3862 (1s) • Cor (1s) • HR 209 (2s) • Inrakluk (2s, 1p: planet b) • 171 Puppis (2s) • HR 5864 (2s)‡ • Mu Arae (1s, 4p: planet d • planet e • planet b • planet c)‡

K
(Orange)

IV	HR 4587 (1s) • Errai (2s, 1p: planet b) • Al Agemim (1s)

V	Gliese 435 (1s) • HR 3259 (1s, 3p: planet b • planet c • planet d) • Gliese 142 (1s) • Gliese 349 (1s) • HR 6518 (1s) • HD 40307 (1s, 3p: planet b • planet c • planet d) • Gliese 428 (2s) • Gliese 707 (1s) • Gliese 204 (1s) • Gliese 167 (1s) • Gliese 775 (1s) • Gliese 425 (2s) • Gliese 716 (1s) • Gliese 146 (1s) • GJ 1267 (1s) • Gliese 556 (1s) • Gliese 69 (1s) • Gliese 174 (1s) • Gliese 868 (1s) • Gliese 528 (2s) • Gliese 656 (1s) • Gliese 5 (2s) • Gliese 615 (1s) • Gliese 898 (3s) • Gliese 532 (1s) • HD 23356 (1s) • Gliese 42 (1s) • Gliese 726 (1s) • Gliese 529 (1s) • Gliese 282 (2s) • Gliese 770 (2s) • Gliese 481 (1s) • Gliese 613 (1s) • HD 150689 (1s) • Gliese 546 (1s) • Gliese 259 (1s) • Gliese 233 (2s) • Gliese 604 (1s) • Gliese 420 (2s) • Gliese 833 (1s) • Gliese 269 (2s) • Gliese 818 (1s) • AB Doradus (2s) • Gliese 14 (1s) • Gliese 52 (1s)‡ • Gliese 483 (1s) • GJ 1279 (1s) • Gliese 141 (1s)‡ • Gliese 225.2 (3s)‡ • Gliese 40 (2s)‡

M V
(Red dwarf)

HD 175224 (2s)‡ • Gliese 215 (1s) • Gliese 400 (2s) • Gliese 123 (1s)

50 – 60 ly

A V
(White)

Castor (6s) • Zosma (2s) • Alhakim (1s) • Sheratan (2s)‡

F
(Yellow-
white)

IV	Denebokab (3s)‡ • I Carinae (1s) • Caph (2s) • Alzirr (1s) • HR 4989 (2s)

V	Phi² Ceti (1s)‡ • Hemelein Secunda (2s)‡ • Tau Boötis (2s, 1p: planet b) • 99 Herculis (3s) • Chi Herculis (1s) • Xi Pegasi (2s) • Alpha Circini (2s) • 10 Ursae Majoris (2s) • Tau¹ Hydrae (2s) • q¹ Eridani (1s, 1p: planet b) • Xi Ophiuchi (2s) • g Lupi (1s) • 58 Ophiuchi (1s) • HR 5356 (2s) • HR 2401 (1s) • Gamma Coronae Australis (2s)‡ • Tau⁶ Eridani (1s) • HR 3079 (2s) • Wasat (3s) • Chi Cancri (1s)‡ • Avis Satyra (1s)‡

G
(Yellow)

IV	Chi Eridani (2s)

V	51 Pegasi (1s, 1p: planet "Bellerophon" b)‡ • GJ 3233 (1s)‡ • HR 7368 (1s, 2bd: brown dwarf C • brown dwarf B) • HR 2007 (1s)‡ • HR 8323 (1s) • 104 Tauri (2s) • HR 7670 (3s, 2p: (planet c • planet b) • GJ 3781 (2s) • HR 3138 (3s) • HR 6516 (2s) • Psi⁵ Aurigae (1s) • HR 5273 (2s) • 9 Puppis (2s) • HR 2225 (1s) • 39 Tauri (2s) • Gliese 295 (1s) • HR 2721 (1s) • Gliese 641 (1s) • Gliese 264.1 (2s) • HR 2997 (1s) • HR 3538 (1s) • HR 7232 (1s) • HR 4864 (1s) • Iota Horologii (1s, 1p: planet b) • 37 Geminorum (1s) • HR 6748 (1s) • 10 Canum Venaticorum (1s) • Rho Coronae Borealis (1s, 1p: planet b) • 39 Serpentis (2s) • HR 7783 (1s) • HR 5384 (1s) • GJ 3021 (1s, 1p: planet b) • 15 Sagittae (1s, 1bd) • HR 7644 (1s) • Iota Pavonis (1s) • HR 4525 (1s) • HR 5534 (1s, 2bd) • 59 Virginis (1s) • Gliese 651 (1s, 1p: planet b) • 70 Virginis (1s, 1p: planet b) • HR 2208 (1s)‡ • Pi Mensae (1s, 1p: planet b) • HR 8314 (1s, 1bd)‡

K
(Orange)

IV	83 Leonis (2s, 2p: planet Bb • planet Bc) • Epsilon Reticuli (1s, 1p: planet b)‡

V	Gliese 156 (1s) • Gliese 862 (1s)‡ • Gliese 227 (1s)‡ • HR 159 (2s)‡ • HD 135599 (1s) • Gliese 778 (1s) • GJ 1175 (1s) • Gliese 782 (1s)‡ • Gliese 397 (1s) • Gliese 496.1 (1s) • HD 139763 (1s) • Gliese 157 (3s)‡ • Gliese 619 (1s) • Gliese 112.1 (1s) • Gliese 156.2 (1s) • Gliese 462 (1s) • Gliese 3 (1s) • Gliese 32 (2s) • Gliese 472 (1s) • Gliese 824 (1s) • Gliese 152 (1s) • Gliese 143 (1s) • GJ 1177 (2s) • Gliese 826.1 (1s) • Gliese 247 (1s) • Gliese 719 (1s) • Gliese 531 (1s) • Gliese 322 (1s) • Gliese 553 (1s) • GJ 3860 (1s, 2p: planet b • planet c) • Gliese 98 (2s) • Gliese 762.1 (1s) • GJ 1181 (2s) • Gliese 786 (1s) • Gliese 56.5 (1s, 1p: planet b) • Gliese 895.4 (1s) • Gliese 200 (2s) • Gliese 886 (1s, 1bd) • Gliese 565 (1s) • Gliese 728 (1s) • GJ 3222 (1s) • Gliese 28 (1s) • GJ 3476 (1s) • Hip 92444 (1s) • Gliese 580 (2s) • Gliese 727 (1s) • GJ 3833 (1s) • Gliese 153 (3s) • Gliese 293.1 (2s) • Gliese 649.1 (3s) • Gliese 241 (1s) • Gliese 340 (2s) • GJ 3633 (1s) • HD 113194 (1s) • Gliese 562 (1s) • GJ 1066 (1s) • Gliese 819 (3s) • Gliese 626 (1s) • HD 35650 (1s) • Gliese 354.1 (2s) • Gliese 365 (1s) • Gliese 171.2 (2s, 1bd) • GJ 1079 (1s) • Gliese 787 (1s) • Gliese 418 (1s) • GJ 2037 (1s) • GJ 3317 (1s) • Gliese 18 (1s) • GJ 1240 (1s) • Gliese 830 (1s)‡ • HD 87883 (1s, 1p: planet b) • Gliese 652 (1s) • 14 Herculis (1s, 1p: planet b) • GJ 4008 (1s)‡ • Gliese 293.2 (1s)‡ • GJ 1106 (1s)‡ • GJ 1120 (2s)‡ • GJ 3488 (1s)‡ • Gliese 355 (1s)‡ • Gliese 131 (1s)‡

M V
(Red dwarf)

GJ 1264 (1s) • GJ 1049 (1s) • Gliese 913 (1s) • Gliese 397.1 (2s)

60 – 70 ly

Giant
star

F III	Tureis (1s)

K III	Menkent (1s) • Aldebaran (2s) • Wei (1s) • Hamal (1s) • Nu Octantis (1s)‡

A V
(White)

Beta Pictoris (1s, 1p: planet b)

F
(Yellow-
white)

IV	Psi Velorum (2s)‡ • Mu Virginis (1s)‡ • Alpha Chamaeleontis (1s) • Metallah (2s) • Eta Crucis (2s) • Tau Cygni (4s) • Theta Draconis (2s) • 40 Leonis (1s)‡ • I Puppis (1s) • Syrma (1s)‡

V	Pherasauval (2s)‡ • Rho Geminorum (2s)‡ • Gliese 41 (1s)‡ • Theta Cygni (2s) • HR 8061 (3s)‡ • Tau Piscis Austrini (1s) • 6 Ceti (1s) • 110 Herculis (2s) • HR 3625 (1s) • HR 1249 (1s) • 1 Centauri (2s) • HR 2251 (3s) • Diadem (3s)‡ • Omicron Aquilae (3s) • c Ursae Majoris (2s) • 74 Orionis (1s) • c Boötis (2s) • 22 Lyncis (2s) • Alpha Caeli (2s) • HR 8853 (1s) • Gamma Doradus (1s) • HR 6349 (1s) • Kappa Tucanae (4s) • Sigma² Ursae Majoris (3s) • HR 8531 (1s) • HR 8843 (1s) • 17 Cygni (2s) • HR 7631 (1s) • HR 1686 (2s, 1p: planet b) • HR 8013 (1s) • 13 Ceti (3s)‡ • Gliese 540.3 (1s) • 71 Orionis (4s)‡ • HR 3578 (1s)‡ • 50 Persei (3s)‡ • B Carinae (1s)‡ • Kappa Reticuli (2s)‡

G
(Yellow)

IV	HR 7683 (2s) • 94 Aquarii (2s)‡ • HR 1322 (2s) • HD 10086 (1s)‡

V	15 Leonis Minoris (1s)‡ • Gliese 161 (1s)‡ • Eta Coronae Borealis (3s)‡ • HR 8148 (2s)‡ • Gliese 36 (1s) • HR 2643 (1s) • Gliese 292.2 (1s) • Gliese 775.1 (1s) • Gliese 790 (1s) • HR 6465 (1s) • Gliese 204.1 (1s) • GJ 3859 (1s) • GJ 3867 (1s) • HD 59747 (1s) • HD 217107 (1s, 2p: planet b • planet c) • HD 220140 (1s) • Gliese 314 (2s) • Gliese 530 (1s) • GJ 1233 (1s) • GJ 3383 (1s)‡ • 53 Aquarii (2s) • Gliese 762.2 (1s) • HR 5 (2s) • GJ 3863 (1s) • 9 Ceti (1s) • GJ 1262 (1s) • Pi¹ Cancri (1s, 1bd) • Gliese 501.2 (1s) • GJ 3593 (1s) • GJ 3255 (1s, 1p: planet b) • HR 7330 (1s) • HR 7260 (2s) • Gliese 59.1 (1s) • HR 7914 (2s) • 51 Arietis (1s)‡ • Gliese 848.4 (1s, 1p: planet b) • HR 5070 (1s)‡ • GJ 3917 (1s)‡ • GJ 3257 (1s)‡ • c (16) Cygni (2s, 1p: planet Bb)‡

K
(Orange)

IV	Tang (1s) • Nu² Canis Majoris (1s)

V	Gliese 260 (1s)‡ • Gliese 339 (2s)‡ • GJ 2102 (1s)‡ • Gliese 158 (1s)‡ • GJ 4134 (1s)‡ • Gliese 315 (1s)‡ • Gliese 509 (2s)‡ • HD 156985 (1s)‡ • Gliese 610 (1s)‡ • Gliese 106 (1s)‡ • Gliese 795 (2s)‡ • Gliese 499 (2s)‡ • Gliese 254 (1s)‡ • HD 152606 (1s)‡ • Gliese 902.1 (1s)‡ • GJ 1094 (1s)‡ • Gliese 715 (1s) • Gliese 249 (1s) • HD 170573 (1s) • Gliese 296 (1s)‡ • Gliese 583 (1s)‡ • GJ 4287 (2s)‡ • Gliese 773 (2s)‡ • Gliese 100 (3s)‡ • Gliese 689 (1s) • Gliese 836.9 (2s)‡ • HD 139477 (1s) • Gliese 646 (3s) • Gliese 576 (1s) • GJ 1246 (1s) • Gliese 825.3 (1s) • GJ 4130 (2s, 1p: planet b) • GJ 1283 (1s) • Gliese 710 (1s) • GJ 3546 (1s)‡ • Gliese 900 (3s) • GJ 1126 (2s) • Gliese 45 (1s) • Gliese 816.1 (2s) • Wo 9126 (1s)‡ • Gliese 894.5 (1s) • Gliese 59 (2s) • Gliese 571.1 (1s) • HD 130004 (1s) • Gliese 627 (2s) • Gliese 906 (1s) • Gliese 81.2 (1s) • Gliese 140.1 (2s) • GJ 3678 (1s) • Gliese 517 (1s) • Gliese 586 (3s) • GJ 1164 (2s) • HD 192263 (1s, 1p: planet b) • HD 35112 (1s) • HD 216520 (1s) • Gliese 292.1 (1s) • Gliese 268.2 (1s) • GJ 1278 (1s) • Gliese 342 (1s) • Gliese 747.3 (1s) • Gliese 221 (1s) • Gliese 456.1 (2s) • HD 110810 (1s) • HD 136923 (1s) • HD 149806 (2s) • HD 106549 (2s)‡ • GJ 3620 (1s) • Gliese 199 (2s) • Gliese 836.8 (1s) • Gliese 840 (1s) • GJ 2001 (1s) • Gliese 558 (1s) • Gliese 765.4 (2s) • Gliese 257.1 (1s) • GJ 1069 (1s, 1bd)‡ • GJ 3769 (1s, 1p: planet b) • GJ 2079 (1s) • Gliese 176.3 (1s) • Wo 9714 (1s) • Gliese 783.2 (2s) • GJ 1172 (1s) • GJ 3358 (1s) • HD 155712 (1s) • Gliese 217 (1s) • HD 332518 (1s) • Gliese 808.2 (1s) • GJ 1108 (2s)‡ • Gliese 53.1 (2s) • GJ 1084 (1s) • GJ 1008 (1s)‡ • Gliese 30 (1s) • Gliese 544 (2s) • GJ 1280 (1s) • GJ 1153 (1s) • Gliese 533 (2s)‡ • Gliese 415 (1s)‡ • Gliese 371 (1s)‡ • HD 220221 (1s) • HD 119802 (1s)‡ • Gliese 491 (2s) • HD 216259 (1s)‡ • Gliese 396 (1s) • Gliese 889 (2s)‡ • GJ 1165 (1s)‡ • Gliese 659 (2s) • Gliese 276 (1s)‡ • GJ 1048 (1s)‡ • Gliese 155.2 (1s)‡ • GJ 3651 (1s)‡ • Gl 857.1 (2s)‡ • Wo 9638 (1s)‡ • GJ 4268 (2s)‡ • GJ 3071 (1s)‡

M V
(Red dwarf)

HD 274255 (1s)‡ • Hip 38594 (1s) • Gliese 328 (1s) • Gliese 330.1 (1s) • GJ 616.2 (1s) • Hip 105533 (1s)‡ • Gliese 336 (1s)‡ • Gliese 122 (1s)‡ • GJ 4254 (1s)‡

In left column are stellar classes of primary members of star systems. ‡Distance error margin extends out of declared distance interval. Components: s – star, bd – brown dwarf, p – planet.

Stars of Cygnus

Bayer	α (Deneb) • β (Albireo) • γ (Sadr) • δ • ε (Gienah) • ζ • η • θ • ι¹ • ι² • κ • λ • μ • ν • ξ • ο¹ • ο² • π¹ (Azelfafage) • π² (Pennae Caudalis) • ρ • σ • τ • υ • φ • χ • ψ • ω¹ • ω² • b¹ • b² • b³ • c • d • e • f¹ • f² • g • A • P

Flamsteed	1 (κ) • 2 • 4 • 6 (β, Albireo) • 7 (ι¹) • 8 • 9 • 10 (ι²) • 11 • 12 (φ) • 13 (θ) • 14 • 15 • 16 (c) • 17 • 18 (δ) • 19 • 20 (d) • 21 (η) • 22 • 23 • 24 (ψ) • 25 • 26 (e) • 27 (b¹) • 28 (b²) • 29 (b³) • 30 • 31 (ο¹) • 32 (ο²) • 33 • 34 (P) • 35 • 36 • 37 (γ, Sadr) • 39 • 40 • 41 • 42 • 43 • 44 • 45 (ω¹) • 46 (ω²) • 47 • 48 • 49 • 50 (α, Deneb) • 51 • 52 • 53 (ε, Gienah) • 54 (λ) • 55 • 56 • 57 • 58 (ν) • 59 (f¹) • 60 • 61 • 62 (ξ) • 63 (f²) • 64 (ζ) • 65 (τ) • 66 (υ) • 67 (σ) • 68 (A) • 69 • 70 • 71 (g) • 72 • 73 (ρ) • 74 • 75 • 76 • 77 • 78 (μ) • 79 • 80 (π¹, Azelfafage) • 81 (π², Pennae Caudalis)

Nearby	61 • GJ 1245

Other	Cygnus X-1 • Cygnus OB2-12 • KY

List

61 Cygni

Contents

Observation history

Properties

Claims of a planetary system

Refining planetary boundaries

See also

Notes

References

External links