9 Cygni

{{Starbox observe

|epoch=J2000

|constell=Cygnus

|ra={{RA|19|34|50.9285}}{{cite DR2}}

|dec={{DEC|+29|27|46.697}}

|appmag_v=5.39{{cite journal|bibcode=2002ApJS..143..513G|doi=10.1086/342942|title=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|year=2002|last1=Ginestet|first1=N.|last2=Carquillat|first2=J. M.|journal=The Astrophysical Journal Supplement Series|volume=143|issue=2|pages=513–537|doi-access=free}} {{nowrap|(5.9 + 6.4){{cite web|url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|title=Sixth Catalog of Orbits of Visual Binary Stars|publisher=United States Naval Observatory|access-date=2020-02-29|archive-date=2017-08-01|archive-url=https://web.archive.org/web/20170801102553/http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|url-status=dead}}}}

}}

{{Starbox character

|type=Red clump + main sequence

|class=G8 IIIa + A2 V

|b-v=0.581

}}

{{Starbox astrometry

|radial_v={{val|20.09|1.98}}

|prop_mo_ra=+14.822

|prop_mo_dec=+13.554

|parallax=5.4904

|p_error=0.0892

|parallax_footnote=

|absmag_v=−0.70

}}

{{Starbox orbit

|reference=

|period=4.56

|axis=0.030

|inclination=114.6

|node=29.3

|periastron=1985.56

|eccentricity=0.82

|periarg=45.5

}}

{{Starbox detail

|component1=9 Cyg A

|mass={{val|2.9|0.4}}

|temperature=5,047

|radius=18.2

|gravity={{val|3.040|0.370}}{{cite journal|bibcode=2016A&A...591A.118S|doi=10.1051/0004-6361/201628497 |arxiv=1605.07384|title=The PASTEL catalogue: 2016 version|journal=Astronomy & Astrophysics|volume=591|pages=A118|year=2016|last1=Soubiran|first1=Caroline|last2=Le Campion|first2=Jean-François|last3=Brouillet|first3=Nathalie|last4=Chemin|first4=Laurent|s2cid=119258214 }}

|metal_fe={{val|-0.260|0.090}}

|component2=9 Cyg B

|mass2={{val|2.7|0.4}}

|temperature2=9,247

|radius2=3.5

|age_myr2=437.1{{cite journal |bibcode=2017MNRAS.468.3533E |title=Models for 60 double-lined binaries containing giants |last1=Eggleton |first1=Peter P. |last2=Yakut |first2=Kadri |journal=Monthly Notices of the Royal Astronomical Society |volume=468 |issue=3 |pages=3533 |year=2017 |arxiv=1611.05041 |doi=10.1093/mnras/stx598 |doi-access=free |s2cid=119476544 }}

}}

{{Starbox catalog

|names={{odlist|BD=+29 3651|HIP=96302|HR=7441|SAO=87385}}{{cite simbad|title=* 9 Cyg|access-date=2020-02-28}}

|component1=9 Cyg A

|names1={{odlist|HD=184759}}

|component2=9 Cyg B

|names2={{odlist|HD=184760}}

}}

{{Starbox reference

|Simbad=9+Cyg

}}

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, 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 {{val|590|u=light-years}} ({{val|182|u=parsecs}}) away.

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. They orbit once every 4.56 years, separated with a semi-major axis of {{val|0.030|u=arcseconds}}. However, the eccentricity is high, at 0.82. 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 and sometimes as a main-sequence star.

9 Cygni

References

See also