ξ Cygni (Latinised as Xi Cygni) is a spectroscopic binary

star A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make ...

in the constellation Cygnus. Its apparent magnitude is 3.73 and it is located around away. The system contains two stars which orbit every 18 years in a mildly eccentric orbit. The primary star is a

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars s ...

with a

spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting th ...

of around K4, while the secondary is an

A-type main-sequence star An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between ...

with a spectral type of A1.5. Stellar winds from the supergiant have been measured at around 50 km/s, but with variations in speed and individual line strengths. ξ Cygni is in the

Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of ...

spacecraft's field of view but no planets have been detected.

References

{{Stars of Cygnus Cygnus (constellation) K-type supergiants Spectroscopic binaries Cygni, Xi 104060 8079 200905 A-type main-sequence stars Cygni, 62 Durchmusterung objects