47 Cygni
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 mas[2] |
| Distance | 4072+965 −773 ly (1249+296 −237 pc)[8] |
| Absolute magnitude (MV) | −4.1 (−4 + −1.5)[3] |
| Orbit[9] | |
| 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[10] M☉ |
| Radius | 601[a] R☉ |
| Surface gravity (log g) | 1.23[12] cgs |
| Temperature | 4,217[12] K |
| Metallicity [Fe/H] | 0.13[12] dex |
| Age | 17.6±0.6[10] Myr |
| 47 Cyg Ab | |
| Mass | 0.57[13] M☉ |
| 47 Cyg B | |
| Mass | 10.96[13] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
47 Cygni is a triple star[4][15] 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.[9] They orbit each other with a period of around 143.69 yr.[13] 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 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.[9]
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.[13] The secondary is a hot B-type main-sequence star, but still 2.5 magnitudes fainter than the primary.[4]
Notes[edit]
- ^ Calculated using an angular diameter of 4.472±0.017 milliarcseconds[11] and a distance of 1249 parsecs.[8]
References[edit]
- ^ "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved October 15, 2022.
- ^ a b c d e 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.
- ^ a b c d 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. Bibcode:2002ApJS..143..513G. doi:10.1086/342942.
- ^ a b c 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. S2CID 14878976.
- ^ {{ | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 }}
- ^ a b Samus, N. N.; Durlevich, O. V.; 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.
- ^ a b Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (March 1, 2021). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv:2012.05220. Bibcode:2021AJ....161..147B. doi:10.3847/1538-3881/abd806. ISSN 0004-6256. Gaia eDR3 source for this star.
- ^ a b c 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.
- ^ a b 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. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
- ^ Baines, Ellyn K.; Clark, James H., III; Schmitt, Henrique R.; Stone, Jordan M.; von Braun, Kaspar (December 1, 2023). "33 New Stellar Angular Diameters from the NPOI, and Nearly 180 NPOI Diameters as an Ensemble". The Astronomical Journal. 166 (6): 268. Bibcode:2023AJ....166..268B. doi:10.3847/1538-3881/ad08be. ISSN 0004-6256.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b c Soubiran, Caroline; et al. (2016). "The PASTEL catalogue: 2016 version". Astronomy and Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
- ^ a b c d Tokovinin, A. (2008). "Comparative statistics and origin of triple and quadruple stars". Monthly Notices of the Royal Astronomical Society. 389 (2): 925–938. arXiv:0806.3263. Bibcode:2008MNRAS.389..925T. doi:10.1111/j.1365-2966.2008.13613.x. S2CID 16452670.
- ^ "47 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved January 14, 2019.
- ^ 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. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.