Summary
26 Cygni is a single[8] star in the northern constellation of Cygnus. It has the Bayer designation e Cygni, while 26 Cygni is the Flamsteed designation. This star is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 5.12.[2] It is located around 451 light-years (138 pc) distant from the Sun,[1] based on parallax measurements. The radial velocity is close to negligible, being measured at −0.3 km/s.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 01m 21.56485s[1] |
| Declination | +50° 06′ 16.8912″[1] |
| Apparent magnitude (V) | 5.12[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | G8 III[3] |
| B−V color index | 1.122[4] |
| Astrometry | |
| Radial velocity (Rv) | −0.25±0.16[1] km/s |
| Proper motion (μ) | RA: +15.520[1] mas/yr Dec.: +5.805[1] mas/yr |
| Parallax (π) | 7.2271 ± 0.0853 mas[1] |
| Distance | 451 ± 5 ly (138 ± 2 pc) |
| Absolute magnitude (MV) | −0.56[5] |
| Details | |
| Mass | 2.44[6] M☉ |
| Radius | 22.27[6] R☉ |
| Luminosity | 204.8[6] L☉ |
| Surface gravity (log g) | 2.50[4] cgs |
| Temperature | 4,700[4] K |
| Metallicity [Fe/H] | −0.09±0.04[5] dex |
| Rotational velocity (v sin i) | 3.63[4] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This object is an evolved giant star with a stellar classification of G8 III;[3] a star that has used up its core hydrogen and left the main sequence. It is most likely (88% chance) on the horizontal branch, in which case stellar modelling yields an estimated 2.44 times the mass of the Sun and 22 times the Sun's radius.[6] It is radiating 205[6] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,700 K.[4]
There is a magnitude 8.94 visual companion at an angular separation of 41.6″ along a position angle of 150°, as of 2014.[9]
References edit
- ^ a b c d e f g h 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. Gaia DR2 record for this source at VizieR.
- ^ a b Fernie, J. D. (1983). "New UBVRI photometry for 900 supergiants". Astrophysical Journal Supplement Series. 52: 7. Bibcode:1983ApJS...52....7F. doi:10.1086/190856.
- ^ a b Abt, Helmut A. (2008). "Visual Multiples. IX. MK Spectral Types". The Astrophysical Journal Supplement Series. 176 (1): 216–217. Bibcode:2008ApJS..176..216A. doi:10.1086/525529.
- ^ a b c d e Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. S2CID 10436552.
- ^ a b 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, S2CID 119257644.
- ^ a b c d e Stock, Stephan; et al. (August 2018). "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search". Astronomy & Astrophysics. 616: 15. arXiv:1805.04094. Bibcode:2018A&A...616A..33S. doi:10.1051/0004-6361/201833111. S2CID 119361866. A33.
- ^ "26 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-11.
- ^ 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.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22