Astronomy:Tau Cygni
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21h 14m 47.4925s[1] |
| Declination | +38° 02′ 43.144″[1] |
| Apparent magnitude (V) | 3.65 - 3.75[2] (3.80 / 6.69[3]) |
| Characteristics | |
| Spectral type | F2 IV[4] + G0 V[citation needed] |
| U−B color index | +0.03 / +0.09 |
| B−V color index | +0.38 / +0.60 |
| Variable type | δ Sct[2] |
| Astrometry | |
| Radial velocity (Rv) | −20.9[4] km/s |
| Proper motion (μ) | RA: +196.99[1] mas/yr Dec.: +410.28[1] mas/yr |
| Parallax (π) | 49.16 ± 0.40[1] mas |
| Distance | 66.3 ± 0.5 ly (20.3 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.21 / 5.00[3] |
| Orbit[5] | |
| Period (P) | 49.5240 years |
| Semi-major axis (a) | 0.92224 |
| Eccentricity (e) | 0.24535 |
| Inclination (i) | 133.242° |
| Longitude of the node (Ω) | 161.343° |
| Periastron epoch (T) | 1938.5919 |
| Argument of periastron (ω) (secondary) | 116.416° |
| Details | |
| τ Cyg A | |
| Mass | 1.65[3] M☉ |
| Radius | 2.48[3] R☉ |
| Surface gravity (log g) | 3.87[3] cgs |
| Temperature | 6,600[3] K |
| Metallicity [Fe/H] | 0.05[3] dex |
| τ Cyg B | |
| Mass | 1.03[3] M☉ |
| Radius | 0.93[3] R☉ |
| Surface gravity (log g) | 4.52[3] cgs |
| Temperature | 5,670[3] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
| A | |
| B | |
Tau Cygni, Latinised from τ Cygni, also named Enduri Senggu,[6] is a binary star system in the constellation Cygnus, approximately 69 light-years away from Earth.[4] This visual binary system has a period of 49.6 years.[3]
The main star, 4th magnitude GJ 822.1 A, is a yellowish white subgiant star of the spectral type F2IV. It therefore has a surface temperature of 6,000 to 7,500 kelvins and is larger, hotter, and several times as bright as the Sun.[7] Its companion, 6th magnitude GJ 822.1 B, is a yellow main sequence star of the spectral type G0V. It is similar to the Sun in size, surface temperature, and luminosity.[8]
Tau Cygni is classified as a δ Scuti variable. The magnitude range is given as 3.65 to 3.75, which is the combined magnitude for both components, although the variable component is A.[2]
This star is part of the Manchu constellation Enduri Senggu, representing a hedgehog goddess.[10] The IAU Working Group on Star Names adopted the name Enduri Senggu for Tau Cygni A on 16 July 2026.[6]
References
- ↑ 1.0 1.1 1.2 1.3 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. ISSN 0004-6361. Bibcode: 2007A&A...474..653V. Hipparcos record for this source at VizieR.
- ↑ 2.0 2.1 2.2 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.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 Fuhrmann, Klaus (February 2008), "Nearby stars of the Galactic disc and halo - IV", Monthly Notices of the Royal Astronomical Society 384 (1): 173–224, doi:10.1111/j.1365-2966.2007.12671.x, Bibcode: 2008MNRAS.384..173F
- ↑ 4.0 4.1 4.2 4.3 "* tau Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+tau+Cyg.
- ↑ "Sixth Catalog of Orbits of Visual Binary Stars". https://crf.usno.navy.mil/usnodocspath?file_name=Orbital%20Elements%3A%20Text&source_file=/data_products/WDS/orb6/orb6orbits.txt.
- ↑ 6.0 6.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ "* tau Cyg A". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+tau+Cyg+A.
- ↑ "* tau Cyg B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+tau+Cyg+B.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Haocheng, Lyu; Mamajek, Eric; Hoffmann, Susanne M. "Enduri Senggu". IAU Working Group on Star Names. https://ase.exopla.net/index.php/Enduri_Senggu.
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