Astronomy:29 Cygni

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Short description: A-type main sequence star in the constellation Cygnus
29 Cygni
V1644CygLightCurve.png
A yellow-light light curve for V1644 Cygni, adapted from Gies and Percy (1977)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus
Right ascension  20h 14m 32.03235s[2]
Declination +36° 48′ 22.7009″[2]
Apparent magnitude (V) 4.94 - 4.97[3]
Characteristics
Evolutionary stage main sequence[4][5]
Spectral type A2 V[6]
B−V color index 0.151±0.018[7]
Variable type δ Sct[8]
Astrometry
Radial velocity (Rv)−17.30±2.80[7] km/s
Proper motion (μ) RA: +68.391[2] mas/yr
Dec.: +70.446[2] mas/yr
Parallax (π)24.5456 ± 0.0724[2] mas
Distance132.9 ± 0.4 ly
(40.7 ± 0.1 pc)
Absolute magnitude (MV)1.78[7]
Details
Mass2.14±0.15[4] M☉
Radius1.2[9] R☉
Luminosity25.2+3.7
−3.1[4] L☉
Surface gravity (log g)4.12±0.2565[5] cgs
Temperature8,790+1,513
−1,292[4] K
Rotational velocity (v sin i)65[4] km/s
Age40[10] Myr
Other designations
b3 Cygni, 29 Cyg, V1644 Cygni, BD+36°3955, HD 192640, HIP 99770, HR 7736, SAO 69678, WDS J20145+3648A, 2MASS J20143203+3648225[11]
Database references
SIMBADdata

29 Cygni is a single[10] star in the northern constellation of Cygnus. It is dimly visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.93.[7] The distance to 29 Cyg, as estimated from an annual parallax shift of 24.5 mas, is 133 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.[7] It is a member of the 30–50 million year old Argus Association of co-moving stars.[12]

This is an A-type main-sequence star with a stellar classification of A2 V.[6] Rodríguez et al. (2000) classify it as a Delta Scuti variable with a frequency of 0.0267 cycles per day.[8] It is a Lambda Boötis[13] class chemically peculiar star and the first such star to be classified as a pulsating variable.[5] 29 Cyg is multi-periodic,[14] small-amplitude variable with a magnitude change of about 0.02 and a dominant period of 39 minutes.[5] A magnetic field has been detected with an averaged quadratic field of (194.5±230.7)×10−4 T.[15] The star has a moderate rate of rotation,[5] showing a projected rotational velocity of 65 km/s.[4] It has double[4] the mass of the Sun and is radiating 25[4] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,790 K.[4]

29 Cygni is listed in multiple star catalogs as having several companions within 4′, including the yellow 7th magnitude HD 192661. All are background objects not physically associated with 29 Cygni itself.[16][17] The naked-eye stars b1 Cygni and b2 Cygni, respectively about one and two degrees away, also lie at different distances to 29 Cygni.

Planetary system

Direct imaging of 29 Cygni b by the Subaru Telescope.

In 2022, a superjovian extrasolar planet HIP 99770 b was discovered by direct imaging and astrometry. Its spectral class is between L7 and L9.5, corresponding to a surface temperature of 1400±100 K.[18]

The 29 Cygni planetary system[18]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(years) 		Eccentricity Inclination Radius
b 13.9+6.1−5.1 MJ 16.9+3.4−1.9 11900+3800−1200 0.25+0.14−0.16 148+13
−11° 		1 RJ

References

  1. ↑ Gies, Douglas R.; Percy, John R. (February 1977). "Photometric variability of 29 Cygni". The Astronomical Journal 82 (2): 166–168. doi:10.1086/112023. Bibcode: 1977AJ.....82..166G. https://ui.adsabs.harvard.edu/abs/1977AJ.....82..166G. Retrieved 28 December 2021. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ Samus, N. N. et al. (2009), "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)", VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1: B/gcvs, Bibcode: 2009yCat....102025S. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, A120, Bibcode: 2012A&A...537A.120Z. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Casas, R. et al. (May 2009), "Asteroseismological Modeling of the Multiperiodic λ Bootis Star 29 Cygni", The Astrophysical Journal 697 (1): 52–534, doi:10.1088/0004-637X/697/1/522, Bibcode: 2009ApJ...697..522C 
  6. ↑ 6.0 6.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  8. ↑ 8.0 8.1 Rodríguez, E. et al. (June 2000), "A revised catalogue of delta Sct stars", Astronomy and Astrophysics Supplement 144 (3): 469–474, doi:10.1051/aas:2000221, Bibcode: 2000A&AS..144..469R. 
  9. ↑ Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P. 
  10. ↑ 10.0 10.1 De Rosa, R. J. et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society 437 (2): 1216, doi:10.1093/mnras/stt1932, Bibcode: 2014MNRAS.437.1216D. 
  11. ↑ "29 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=29+Cyg. 
  12. ↑ Malo, Lison et al. (January 2013), "Bayesian Analysis to Identify New Star Candidates in Nearby Young Stellar Kinematic Groups", The Astrophysical Journal 762 (2): 50, doi:10.1088/0004-637X/762/2/88, 88, Bibcode: 2013ApJ...762...88M. 
  13. ↑ Murphy, Simon J. et al. (October 2015), "An Evaluation of the Membership Probability of 212 λ Boo Stars. I. A Catalogue", Publications of the Astronomical Society of Australia 32: 43, doi:10.1017/pasa.2015.34, e036, Bibcode: 2015PASA...32...36M 
  14. ↑ Mkrtichian, D. E. et al. (October 2007), "Multimode Pulsations of the λ Bootis Star 29 Cygni: The 1995 and 1996 Multisite Campaigns", The Astronomical Journal 134 (4): 1713, doi:10.1086/521434, Bibcode: 2007AJ....134.1713M. 
  15. ↑ Bychkov, V. D. et al. (August 2003), "Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars", Astronomy and Astrophysics 407 (2): 631–642, doi:10.1051/0004-6361:20030741, Bibcode: 2003A&A...407..631B. 
  16. ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M. 
  17. ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 
  18. ↑ 18.0 18.1 Currie, Thayne et al. (2022), Direct Imaging and Astrometric Discovery of a Superjovian Planet Orbiting an Accelerating Star 



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