Astronomy:47 Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 33m 54.18821s[2] |
| Declination | +35° 15′ 03.02810″[2] |
| Apparent magnitude (V) | 4.61[3] (4.84 + 7.30)[4] |
| Characteristics | |
| Spectral type | K6: Ib + B2.5:[3] |
| B−V color index | 1.593±0.023[5] |
| Variable type | Lc[6] |
| Astrometry | |
| Radial velocity (Rv) | −4.6±0.3[7] km/s |
| Proper motion (μ) | RA: −3.746[2] mas/yr Dec.: −3.408[2] mas/yr |
| Parallax (π) | 0.7605 ± 0.2285[2] mas |
| Distance | approx. 4,000 ly (approx. 1,300 pc) |
| Absolute magnitude (MV) | −4.1 (−4 + −1.5)[3] |
| Orbit[8] | |
| Period (P) | 1117±11 d |
| Eccentricity (e) | 0.00 (assumed) |
| Periastron epoch (T) | 2,447,088±10 JD |
| Semi-amplitude (K1) (primary) | 2.0±0.1 km/s |
| Details | |
| 47 Cyg Aa | |
| Mass | 12.1±0.2[9] M☉ |
| Radius | 575[10] R☉ |
| Surface gravity (log g) | 1.23[11] cgs |
| Temperature | 4,217[11] K |
| Metallicity [Fe/H] | 0.13[11] dex |
| Age | 17.6±0.6[9] Myr |
| 47 Cyg Ab | |
| Mass | 0.57[12] M☉ |
| 47 Cyg B | |
| Mass | 10.96[12] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
47 Cygni is a triple star[4][14] system in the northern constellation of Cygnus, and is located around 4,000 light years from the Earth. It is visible to the naked eye with a combined apparent visual magnitude of 4.61.[3] The system is moving closer to the Earth with a heliocentric radial velocity of −4.6 km/s.[7]
The dual nature of this system was recognized by Annie Cannon in 1912, and she assigned the pair separate Henry Draper Catalogue identifiers.[8] They orbit each other with a period of around 143.69 yr.[12] The primary component is itself a spectroscopic binary in a near circular orbit with a period of around 3.06 yr. The a sin i value for the primary is 30.8 ± 1.6 Gm (0.206 ± 0.011 astronomical unit|AU), where a is the semimajor axis and i is the orbital inclination. It has been repeatedly resolved by speckle interferometery since 1973. Radio emission was detected from this system in 1985/86.[8]
The supergiant primary is a slow irregular variable with an amplitude of about 0.1 magnitudes.[6] Its close companion has 57% of the mass of the Sun.[12] The secondary is a hot B-type main-sequence star, but still 2.5 magnitudes fainter than the primary.[4]
References
- ↑ "/ftp/cats/more/HIP/cdroms/cats". Strasbourg astronomical Data Center. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats.
- ↑ 2.0 2.1 2.2 2.3 2.4 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. Bibcode: 2018A&A...616A...1G.
- ↑ 3.0 3.1 3.2 3.3 Ginestet, N.; Carquillat, J. M. (December 2002), "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components", The Astrophysical Journal Supplement Series 143 (2): 513–537, doi:10.1086/342942, Bibcode: 2002ApJS..143..513G.
- ↑ 4.0 4.1 4.2 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 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, Bibcode: 2009yCat....102025S.
- ↑ 7.0 7.1 Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 8.0 8.1 8.2 Griffin, R. F. (June 1992), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 104: 47 Cygni", The Observatory 112: 111–120, Bibcode: 1992Obs...112..111G.
- ↑ 9.0 9.1 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ Stassun K.G. (October 2019). "The revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S.
- ↑ 11.0 11.1 11.2 Soubiran, Caroline et al. (2016), "The PASTEL catalogue: 2016 version", Astronomy and Astrophysics 591: A118, doi:10.1051/0004-6361/201628497, Bibcode: 2016A&A...591A.118S.
- ↑ 12.0 12.1 12.2 12.3 Tokovinin, A. (2008), "Comparative statistics and origin of triple and quadruple stars", Monthly Notices of the Royal Astronomical Society 389 (2): 925–938, doi:10.1111/j.1365-2966.2008.13613.x, Bibcode: 2008MNRAS.389..925T.
- ↑ "47 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=47+Cyg.
- ↑ Mason, Brian D. et al. (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.
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