Astronomy:T Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 47m 10.75239s[1] |
| Declination | +34° 22′ 26.8374″[1] |
| Apparent magnitude (V) | 4.93[2] + 10.03[3] |
| Characteristics | |
| Spectral type | K3 III[4] |
| B−V color index | 1.294±0.003[2] |
| Variable type | Lb:[5] |
| Astrometry | |
| Radial velocity (Rv) | −23.9±0.3[6] km/s |
| Proper motion (μ) | RA: +39.637[1] mas/yr Dec.: +8.068[1] mas/yr |
| Parallax (π) | 8.4327 ± 0.1348[1] mas |
| Distance | 387 ± 6 ly (119 ± 2 pc) |
| Absolute magnitude (MV) | −0.74[2] |
| Details | |
| A | |
| Radius | 28.19+0.67 −0.86[1] R☉ |
| Luminosity | 241.4±4.5[1] L☉ |
| Surface gravity (log g) | 2.12[7] cgs |
| Temperature | 4,285+50 −67[1] K |
| Metallicity [Fe/H] | −0.12[7] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
T Cygni is a binary star[9] system in the northern constellation of Cygnus. It is a faint system but visible to the naked eye with a combined apparent visual magnitude of 4.93.[2] Based upon an annual Parallax shift of 8.4 mas,[1] it is located 387 light years away. It is moving closer to the Earth with a heliocentric radial velocity of −24 km/s.[6]
The primary, component A, is a variable star, most likely of the slow irregular type, which ranges in magnitude from 4.91 down to 4.96.[5] It is a giant star with a stellar classification of K3 III,[4] which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. The star has expanded to 28 times the radius of the Sun.[1] It is radiating 241 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,285 K.[1]
The secondary companion, component B, is a magnitude 10.03 star located at an angular separation of 8.10″ along a position angle of 120°, as of 2012. In 1877 it was separated by 10.0″ with nearly the same position angle (121°).[3]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 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. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
- ↑ 4.0 4.1 Herbig, George H.; Spalding, John F., Jr. (January 1955). "Axial Rotation and Line Broadening in Stars of Spectral Types F0-K5". Astrophysical Journal 121: 118. doi:10.1086/145969. Bibcode: 1955ApJ...121..118H.
- ↑ 5.0 5.1 Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 6.0 6.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 7.0 7.1 McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances". Astrophysical Journal Supplement Series 74: 1075–1128. doi:10.1086/191527. Bibcode: 1990ApJS...74.1075M.
- ↑ "T Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=T+Cyg.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E.
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