T Cygni
T Cygni
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
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 | 7000129400000000000♠1.294±0.003[2] |
Variable type | Lb:[5] |
| Astrometry | |
| Radial velocity (Rv) | 2998761000000000000♠−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 | |
| T Cyg A | |
| Radius | 27[7] R☉ |
| Luminosity | 333.48[2] L☉ |
| Surface gravity (log g) | 2.12[8] cgs |
| Temperature | 4,190[8] K |
Metallicity [Fe/H] | −0.12[8] dex |
| Other designations | |
T Cyg, BD+33° 4028, HD 198134, HIP 102571, HR 7956, SAO 70499, WDS J20472+3422A[9] | |
| Database references | |
| SIMBAD | data |
T Cygni is a binary star[10] 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 6992407243492132011♠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 measured angular diameter of this star, after correction for limb darkening, is 6992102295686714112♠2.11±0.02 mas.[11] At the estimated distance of this star, this yields a physical size of about 27 times the Sun's radius.[7] It is radiating 333[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,190 K.[8]
The secondary companion, component B, is a magnitude 10.03 star located at an angular separation of 6995392699081698725♠8.10″ along a position angle of 120°, as of 2012. In 1877 it was separated by 6995484813681109537♠10.0″ with nearly the same position angle (121°).[3]
References[edit]
^ abcdef 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..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ abcdef Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
^ ab Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
^ ab 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. Bibcode:1955ApJ...121..118H. doi:10.1086/145969.
^ ab 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. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085.
^ ab Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
^ ab Lang, Kenneth R. (2006). "Astrophysical formulae". Astronomy and astrophysics library. 1 (3 ed.). Birkhäuser. ISBN 3-540-29692-1.. The radius (R*) is given by:
- 2⋅R∗=(10−3⋅118.6⋅2.11) AU0.0046491 AU/R⨀≈53.8⋅R⨀{displaystyle {begin{aligned}2cdot R_{*}&={frac {(10^{-3}cdot 118.6cdot 2.11) {text{AU}}}{0.0046491 {text{AU}}/R_{bigodot }}}\&approx 53.8cdot R_{bigodot }end{aligned}}}
- 2⋅R∗=(10−3⋅118.6⋅2.11) AU0.0046491 AU/R⨀≈53.8⋅R⨀{displaystyle {begin{aligned}2cdot R_{*}&={frac {(10^{-3}cdot 118.6cdot 2.11) {text{AU}}}{0.0046491 {text{AU}}/R_{bigodot }}}\&approx 53.8cdot R_{bigodot }end{aligned}}}
^ abcd 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. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527.
^ "T Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 September 2018.
^ 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
^ Richichi, A.; et al. (February 2005). "CHARM2: An updated Catalog of High Angular Resolution Measurements". Astronomy and Astrophysics. 431 (2): 773–777. Bibcode:2005A&A...431..773R. doi:10.1051/0004-6361:20042039.
Categories:
- K-type giants
- Slow irregular variables
- Cygnus (constellation)
- Durchmusterung objects
- Henry Draper Catalogue objects
- Hipparcos objects
- HR objects
- Objects with variable star designations
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