Astronomy:72 Cygni

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Short description: K-type giant star in the constellation Cygnus
72 Cygni
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus
Right ascension  21h 34m 46.58574s[1]
Declination +38° 32′ 02.6267″[1]
Apparent magnitude (V) 4.87[2]
Characteristics
Spectral type K0.5 III Fe0.5[3] or K0.5 III CN 0.5[4] + M5[5]
B−V color index 1.092[6]
Astrometry
Radial velocity (Rv)−68.12±0.11[6] km/s
Proper motion (μ) RA: +113.665[1] mas/yr
Dec.: +100.403[1] mas/yr
Parallax (π)14.2468 ± 0.1339[1] mas
Distance229 ± 2 ly
(70.2 ± 0.7 pc)
Absolute magnitude (MV)0.62[2]
Details
Mass1.70[7] M
Radius14[6] R
Luminosity69[7] L
Surface gravity (log g)2.68±0.04[8] cgs
Temperature4,640±25[7] K
Metallicity [Fe/H]0.18[8] dex
Rotational velocity (v sin i)1.4[6] km/s
Age900±200[8] Myr
Other designations
72 Cyg, BD+37°4359, FK5 3722, HD 205512, HIP 106551, HR 8255, SAO 71480[9]
Database references
SIMBADdata

72 Cygni is a star in the northern constellation of Cygnus, located 299 light years from the Sun[1] and a member of the Hercules stream.[8] It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.87.[2] 72 Cyg is moving closer to the Earth with a heliocentric radial velocity of −68 km/s.[6] It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.154 per year.[10]

This is an aging giant star with a stellar classification of K0.5 III Fe0.5,[3] where the suffix notation indicates a mild underabundance of iron in the spectrum. It has 1.7[7] times the mass of the Sun but has expanded to 14[6] times the Sun's radius. The star is radiating 69[7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,640 K.[7]

72 Cygni has a wide companion at an angular separation of 66.1″, corresponding to a projected separation of 4,690 astronomical unit|AU. This star has a J band (infrared) magnitude of 13.224±0.025 and a class of M5.[5]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode1989ApJS...71..245K. 
  4. Keenan, Philip C. et al. (July 1987). "Recognition and classification of strong-CN giants". Publications of the Astronomical Society of the Pacific 99: 629–636. doi:10.1086/132025. Bibcode1987PASP...99..629K. 
  5. 5.0 5.1 Deacon, Niall R. et al. (September 2014), "Wide Cool and Ultracool Companions to Nearby Stars from Pan-STARRS 1", The Astrophysical Journal 792 (2): 40, doi:10.1088/0004-637X/792/2/119, 119, Bibcode2014ApJ...792..119D. 
  6. 6.0 6.1 6.2 6.3 6.4 6.5 Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode2008AJ....135..209M. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode2015AJ....150...88L. 
  8. 8.0 8.1 8.2 8.3 Ramya, P. et al. (August 2016), "Chemical compositions and kinematics of the Hercules stream", Monthly Notices of the Royal Astronomical Society 460 (2): 1356−1370, doi:10.1093/mnras/stw852, Bibcode2016MNRAS.460.1356R. 
  9. "72 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=72+Cyg. 
  10. Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal 129 (3): 1483–1522, doi:10.1086/427854, Bibcode2005AJ....129.1483L.