10 Cygni

Iota2 Cygni
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension  19h 29m 42.36s[1]
Declination +51° 43′ 47.2″[1]
Apparent magnitude (V) 3.76[2]
Spectral type A5V[3]
B−V color index +0.148±0.001[2]
Radial velocity (Rv)−19.5±2.7[2] km/s
Proper motion (μ) RA: +20.59[1] mas/yr
Dec.: +128.33[1] mas/yr
Parallax (π)26.88 ± 0.11[1] mas
Distance121.3 ± 0.5 ly
(37.2 ± 0.2 pc)
Absolute magnitude (MV)+0.91[2]
Mass1.80[4] M
[5] R
Luminosity34.5±0.5[5] L
Surface gravity (log g)3.91[4] cgs
Temperature8,216±279[4] K
Rotational velocity (v sin i)240[6] km/s
Age577[4] Myr
Other designations
ι2 Cyg, 10 Cygni, BD+51° 2605, GC 26947, HD 184006, HIP 95853, HR 7420, SAO 31702[7]
Database references

Iota2 Cygni, Latinized from ι2 Cygni and often simply called ι Cygni,[8] is a single[9] star in the constellation Cygnus. It is visible to the naked eye as a white-hued point of light with an apparent visual magnitude of 3.76.[2] Located around 121.3 light-years distant from the Sun based on parallax,[1] it is drifting closer with a radial velocity of −19.5 km/s and is expected to come to within 92 light-years in around 783,000 years.[2]

This it is an A-type main-sequence star with a stellar classification of A5V,[3] a star that is currently fusing its core hydrogen. It is around 577[4] million years old and is spinning rapidly with a projected rotational velocity of 240 km/s.[6] The star has 1.8[4] times the mass of the Sun and 3.8[5] times the Sun's radius. It is radiating 35[5] times the luminosity of the Sun from its photosphere at an effective temperature of 8,216 K.[4] Based on rapid changes in the strength of a singly-ionized calcium absorption line, the star is likely host to a circumstellar disk.[10]


  1. ^ a b c d e f van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. ^ a b c d e f Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
  3. ^ a b Chesneau, O.; et al. (2010). "Time, spatial, and spectral resolution of the Hα line-formation region of Deneb and Rigel with the VEGA/CHARA interferometer". Astronomy and Astrophysics. 521: A5. arXiv:1007.2095. Bibcode:2010A&A...521A...5C. doi:10.1051/0004-6361/201014509.
  4. ^ a b c d e f g David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  5. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. ^ a b Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  7. ^ "iot02 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-11.
  8. ^ Kaler, Jim. "Kappa, Iota Cygni". STARS. Retrieved 2016-05-19.
  9. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x
  10. ^ Montgomery, Sharon L.; Welsh, Barry Y. (October 2012). "Detection of Variable Gaseous Absorption Features in the Debris Disks Around Young A-type Stars". Publications of the Astronomical Society of the Pacific. 124 (920): 1042–1056. Bibcode:2012PASP..124.1042M. doi:10.1086/668293.