Astronomy:Psi Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 55m 37.78622s[1] |
| Declination | +52° 26′ 20.2116″[1] |
| Apparent magnitude (V) | 4.92[2] (5.05 + 7.61)[3] |
| Characteristics | |
| A | |
| Spectral type | A4 Vn[4] |
| U−B color index | +0.05[2] |
| B−V color index | +0.13[2] |
| B | |
| Spectral type | F4 V[5] |
| Astrometry | |
| Radial velocity (Rv) | −10[6] km/s |
| Proper motion (μ) | RA: −37.62[1] mas/yr Dec.: −31.13[1] mas/yr |
| Parallax (π) | 11.59 ± 0.38[1] mas |
| Distance | 281 ± 9 ly (86 ± 3 pc) |
| Absolute magnitude (MV) | +0.23[7] |
| Orbit[8] | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 54.08 yr |
| Semi-major axis (a) | 0.141″ |
| Eccentricity (e) | 0.484 |
| Inclination (i) | 112.0° |
| Details | |
| ψ Cyg Aa | |
| Luminosity | 62[9] L☉ |
| Temperature | 7,971[9] K |
| Rotational velocity (v sin i) | 207[4] km/s |
| ψ Cyg B | |
| Rotational velocity (v sin i) | 120[10] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
ψ Cygni, Latinised as Psi Cygni, is a triple star[3] system in the constellation called Cygnus. With a combined apparent visual magnitude of 4.92,[2] it is visible to the naked eye. As of 2002, the inner pair, components Aa and Ab, had an angular separation of 0.10 arc seconds along a position angle of 77.6°.[12] Their combined visual magnitude is 5.05.[3] Relative to this pair, the third member of the system, magnitude 7.61[3] component B, had an angular separation of 2.87 arc seconds along a position angle of 175.6° as of 2010.[13] Based upon an annual parallax shift of 11.59 mas,[1] Psi Cygni is located around 281 light years from the Sun.
The brighter member of the system, presumably component Aa, displays the spectrum of an A-type main sequence star with a stellar classification of A4 Vn,[4] where the 'n' notation indicates "nebulous" absorption lines due to rapid rotation. It appears to be a spinning with a projected rotational velocity of 207.[4] The component is radiating 62 times the solar luminosity from its outer atmosphere at an effective temperature of 7,971 K.[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 3.2 3.3 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 4.0 4.1 4.2 4.3 Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R.
- ↑ Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal 81: 245–249, doi:10.1086/111879, Bibcode: 1976AJ.....81..245E.
- ↑ Evans, D. S. (June 20–24, 1966). "Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30". in Batten, Alan Henry; Heard, John Frederick. 30. 57. Bibcode: 1967IAUS...30...57E.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ Tokovinin, Andrei (2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series 235 (1): 6. doi:10.3847/1538-4365/aaa1a5. Bibcode: 2018ApJS..235....6T.
- ↑ 9.0 9.1 9.2 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ Uesugi, Akira; Fukuda, Ichiro (1970). "Catalogue of rotational velocities of the stars". Bibcode: 1970crvs.book.....U.
- ↑ "* psi Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+psi+Cyg.
- ↑ Roberts, Lewis C. Jr. (May 2011), "Astrometric and photometric measurements of binary stars with adaptive optics: observations from 2002", Monthly Notices of the Royal Astronomical Society 413 (2): 1200–1205, doi:10.1111/j.1365-2966.2011.18205.x, Bibcode: 2011MNRAS.413.1200R.
- ↑ Mason, Brian D. et al. (August 2011), "Speckle Interferometry at the U.S. Naval Observatory. XVII.", The Astronomical Journal 142 (2): 4, doi:10.1088/0004-6256/142/2/46, 46, Bibcode: 2011AJ....142...46M.
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