9 Cygni

Short description: Star in the constellation Cygnus

9 Cygni  Observation data
Equinox J2000.0]] (ICRS)

Constellation | Cygnus
Right ascension |  19h 34m 50.9285s[1]
Declination | +29° 27′ 46.697″[1]
Apparent magnitude (V) | 5.39[2] (5.9 + 6.4)[3]
Characteristics
Evolutionary stage | Red clump \+ main sequence[4]
Spectral type | G8 IIIa + A2 V[4]
B−V color index | 0.581[2]
Astrometry
Radial velocity (Rv)| 20.09±1.98[1] km/s
Proper motion (μ)|  RA: +14.822[1] mas/yr
Dec.: +13.554[1] mas/yr
Parallax (π)| 5.4904 ± 0.0892[1] mas
Distance| 594 ± 10 ly
(182 ± 3 pc)
Absolute magnitude (MV)| −0.70[2]
Orbit[3]
Period (P)| 4.56 yr
Semi-major axis (a)| 0.030″
Eccentricity (e)| 0.82
Inclination (i)| 114.6°
Longitude of the node (Ω)| 29.3°
Periastron epoch (T)| 1985.56
Argument of periastron (ω)
(secondary)| 45.5°
Details
9 Cyg A
Mass| 2.9±0.4[2] M☉
Radius| 18.2[4] R☉
Surface gravity (log g)| 3.040±0.370[5] cgs
Temperature| 5,047[4] K
Metallicity [Fe/H]| −0.260±0.090[5] dex
9 Cyg B
Mass| 2.7±0.4[2] M☉
Radius| 3.5[4] R☉
Temperature| 9,247[4] K
Age| 437.1[4] Myr
Other designations

BD+29 3651, HIP 96302, HR 7441, SAO 87385[6]

9 Cyg A: {{{names1}}}
9 Cyg B: {{{names2}}}
Database references
SIMBAD| data

9 Cygni is a binary star system in the northern constellation of Cygnus. 9 Cygni is its Flamsteed designation. The two stars have a combined magnitude of 5.39,[2] so it can be seen with the naked eye under good viewing conditions. Parallax measurements made by Gaia put the star at a distance of around 590 light-years (182 parsecs) away.[1]

The two stars of 9 Cygni are a G-type giant and an A-type star. Both stars are over twice as massive as the Sun.[2] They orbit once every 4.56 years, separated with a semi-major axis of 0.030 arcseconds. However, the eccentricity is high, at 0.82.[3] The primary is a red clump giant, a star on the cool end of the horizontal branch fusing helium in its core. The secondary star has begun to evolve off the main sequence; it is sometimes classified as a giant star[2] and sometimes as a main-sequence star.[4]

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 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.
2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Ginestet, N.; Carquillat, J. M. (2002). "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components". The Astrophysical Journal Supplement Series 143 (2): 513–537. doi:10.1086/342942. Bibcode: 2002ApJS..143..513G.
3. ↑ 3.0 3.1 3.2 "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6.
4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Eggleton, Peter P.; Yakut, Kadri (2017). "Models for 60 double-lined binaries containing giants". Monthly Notices of the Royal Astronomical Society 468 (3): 3533. doi:10.1093/mnras/stx598. Bibcode: 2017MNRAS.468.3533E.
5. ↑ 5.0 5.1 Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics 591: A118. doi:10.1051/0004-6361/201628497. Bibcode: 2016A&A...591A.118S.
6. ↑ "* 9 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=*+9+Cyg.

## See also

* Spectroscopic binary

* v
* t
* e

Constellation of Cygnus

* List of stars in Cygnus

Stars|

| Bayer|

* α (Deneb)
* β (Albireo)
* γ (Sadr)
* δ (Fawaris)
* ε (Aljanah)
* ζ
* η
* θ
* ι1
* ι2
* κ
* λ
* μ
* ν
* ξ
* π1 (Azelfafage)
* π2
* ρ
* σ
* τ
* υ
* φ
* χ
* ψ
* ω1
* ω2
* P
* Q

|

Flamsteed|

* 2
* 4
* 8
* 9
* 14
* 15
* 16 (c)
* 17
* 20 (d)
* 22
* 23
* 26 (e)
* 27 (b1)
* 28 (b2)
* 29 (b3)
* 30
* 31
* 32
* 33
* 35
* 39
* 41
* 47
* 52
* 55
* 56
* 57
* 59 (f1)
* 61
* 63 (f2)
* 68 (A)
* 71 (g)
* 72
* 74
* 75

Variable|

* R
* T
* W
* RW
* SS
* TT
* BC
* BI
* CH
* KY
* V404
* V476
* V1057
* V1143
* V1191
* V1489
* V1500
* V1668
* V1974
* V2513

HR|

* 7633
* 7912
* 8193

HD|

* 185269
* 185435
* 187123
* 188753
* 191806

Gliese|

* 777
* 806
* 1245

Kepler|

* 5
* 6
* 11
* 15
* 16
* 17
* 18
* 22
* 23
* 27
* 28
* 29
* 31
* 32
* 33
* 34
* 35
* 36
* 39
* 40
* 41
* 42
* 43
* 44
* 45
* 47
* 51
* 56
* 61
* 66
* 67
* 68
* 69
* 70
* 78
* 80
* 84
* 86
* 89
* 107
* 182
* 186
* 223
* 371
* 419
* 432
* 451
* 452
* 1229
* 1520
* 1625

Other|

* AFGL 2591
* BD+40° 4210
* BD+43 3654
* Cygnus OB2 #8A
* Cygnus OB2 #12
* Cygnus X-1
* Cygnus X-3
* G 208-44
* G 208-45
* HAT-P-7
* HAT-P-11
* HAT-P-17
* KELT-9
* KIC 8462852
* KIC 9832227
* KIC 11026764
* KOI-74
* KOI-81
* KOI-256
* KPD 1930+2752
* MWC 349
* N6946-BH1
* NML Cygni
* PH1
* PSR J2032+4127
* W75N(B)-VLA2
* WISE J2000+3629
* WR 134
* WR 135
* WR 136
* WR 137
* WR 140
* WR 142
* WR 147
* WR 148

Former|

* 3

Star
clusters|

| Association|

* Cygnus OB2
* Cygnus OB7

|

Open|

* DR 6
* IC 5146
* Messier 29
* Messier 39
* NGC 6811
* NGC 6819
* NGC 6834
* NGC 6866
* NGC 6871
* NGC 6910

Molecular
clouds|

* Cygnus X (including DR 21)

Nebulae|

| Dark|

* Barnard 146
* Barnard 147
* IC 5146
* L1014

|

H II|

* NGC 6914
* North America Nebula
* Pelican Nebula
* Sadr Region
* Sh2-101
* Sh2-106

Planetary|

* Abell 78
* Egg Nebula
* IRAS 19475+3119
* Kronberger 61
* M1-92
* NGC 6826
* NGC 6881
* NGC 6884
* NGC 7008
* NGC 7026
* NGC 7027
* NGC 7048
* Soap Bubble Nebula

WR|

* Crescent Nebula

SNR|

* Cygnus Loop (including Veil Nebula)

Galaxies|

| NGC|

* 6801
* 6946
* 7013

|

Other|

* 3C 438
* Cygnus A

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/9 Cygni. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:9_Cygni&oldid=481286"
*[RA:]: Right Ascension
*[Dec.:]: Declination
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template