mu Cygni

{{short description|Star in the constellation Cygnus}}

{{Starbox begin

| name = Mu Cygni

}}

{{Starbox observe

| epoch = J2000

| constell = Cygnus

| ra = {{RA|21|44|08.57767}}{{cite DR2|1801210568415251072}}

| dec = {{DEC|+28|44|33.4567}}

| appmag_v = 4.49{{citation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | postscript=. | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}

}}

{{Starbox character

| class = {{nowrap|F6V + G2V}}{{citation | display-authors=1 | last1=Mason | first1=Brian D. | last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I. | last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E. | title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466–3471 | date=December 2001 | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=B/wds/wds&WDS=21441%2B2845 Vizier catalog entry]

| b-v = {{Val|+0.512|0.007}}

}}

{{Starbox astrometry

| radial_v = +16.95{{citation | last1=Maldonado | first1=J. | last2= Martínez-Arnáiz | first2=R. M. | last3=Eiroa | first3=C. | last4=Montes | first4=D. | last5=Montesinos | first5=B. | title=A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups | journal=Astronomy and Astrophysics | volume=521 | pages=A12 |date=October 2010 | doi=10.1051/0004-6361/201014948 | bibcode=2010A&A...521A..12M |arxiv = 1007.1132 | s2cid=119209183 }}

| prop_mo_ra = +257.012

| prop_mo_dec = −239.009

| parallax = 45.2207

| p_error = 0.2383

| parallax_footnote =

| absmag_v = 2.75

}}

{{Starbox astrometry|no_heading=y

| component1 = μ¹ Cyg

| absmag_bol = {{Val|2.91|0.06}}{{cite journal|bibcode=2011MNRAS.414.2893F|doi=10.1111/j.1365-2966.2011.18476.x|title=Nearby stars of the Galactic disc and halo - V|journal=Monthly Notices of the Royal Astronomical Society|volume=414|issue=4|pages=2893–2922|year=2011|last1=Fuhrmann|first1=Klaus|doi-access=free}}

| absmag_v = 2.77

| component2 = μ² Cyg

| absmag_bol2 = {{Val|4.32|0.06}}

| absmag_v2 = 4.38

}}

{{Starbox orbit

| reference = {{citation | display-authors=1 | last1=Pourbaix | first1=D. | last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H. | last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I. | last6=Levato | first6=H. | last7=Morrell | first7=N. I. | last8=Torres | first8=G. | last9=Udry | first9=S. | year=2004 | pages=727–732 | volume=424 | issue=2 | title=SB9: The Ninth Catalogue of Spectroscopic Binary Orbits | journal=Astronomy & Astrophysics | bibcode=2004A&A...424..727P | doi=10.1051/0004-6361:20041213 | postscript=. | arxiv=astro-ph/0406573 | s2cid=119387088 }}

| period = 789

| axis = 5.32

| eccentricity = 0.66

| inclination = 75.5

| node = 110.1

| periastron = 1958.0

| periarg = 145.7

}}

{{Starbox detail

| source = {{cite journal |bibcode=2017AJ....153...21L |title=Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants |journal=The Astronomical Journal |volume=153 |issue=1 |pages=21 |last1=Luck |first1=R. Earle |year=2017 |arxiv=1611.02897 |doi=10.3847/1538-3881/153/1/21 |s2cid=119511744 |doi-access=free }}

| component1 = μ¹ Cyg

| luminosity = 6.0

| temperature = 6,354

| gravity = 3.93

| metal_fe = {{Val|−0.16}}

| rotational_velocity = 11.6

| mass = 1.31

| radius = {{Val|1.88|0.07}}

| age_gyr = 3.46

| component2 = μ² Cyg

| luminosity2 = 1.4

| temperature2 = 5,998

| gravity2 = 4.33

| metal2_fe = {{Val|−0.24}}

| rotational_velocity2 = 6.4

| mass2 = 0.99

| radius2 = {{Val|1.08|0.05}}

| age_gyr2 = 7.11

}}

{{Starbox catalog

| names = {{odlist|F=78 Cyg|BD=+28°4169|CCDM=J21442+2845AB|HIP=107310|WDS=J21441+2845AB}}{{cite simbad|title = CCDM J21442+2845AB|access-date = 2016-04-08}}

| component1 = μ¹ Cyg

| names1 = {{odlist|HD=206826|HR=8309|SAO=89940}}

| component2 = μ² Cyg

| names2 = {{odlist|HD=206827|HR=8310|SAO=89939}}

}}

{{Starbox reference

| Simbad = mu.+Cyg | sn=μ Cyg

| Simbad2 = mu.01+Cyg | sn2= μ¹ Cyg

| Simbad3 = mu.02+Cyg | sn3= μ² Cyg

}}

{{Starbox end}}

μ Cygni, Latinised as Mu Cygni, is a binary star{{Cite journal | doi = 10.1111/j.1365-2966.2008.13596.x| title = A catalogue of multiplicity among bright stellar systems| year = 2008| last1 = Eggleton | first1 = P. P.| last2 = Tokovinin | first2 = A. A.| journal = Monthly Notices of the Royal Astronomical Society| volume = 389| issue = 2| pages = 869| doi-access = free| bibcode = 2008MNRAS.389..869E|arxiv = 0806.2878 | s2cid = 14878976}} [http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ570887621365&-out.add=.&-source=J/MNRAS/389/869/table1&recno=4155 Vizier catalog entry] system in the northern constellation of Cygnus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.49. The system is located 72 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +17 km/s.

The pair have an orbital period of around 800 years, with a semimajor axis of {{Val|5|ul=arcsecond}} and an eccentricity around 0.6.{{citation | display-authors=1 | last1=Malkov | first1=O. Yu. | last2=Tamazian | first2=V. S. | last3=Docobo | first3=J. A. | last4=Chulkov | first4=D. A. | title=Dynamical masses of a selected sample of orbital binaries | journal=Astronomy & Astrophysics | volume=546 | issue=A69 | pages=A69 | date=October 2012 | bibcode=2012A&A...546A..69M | doi=10.1051/0004-6361/201219774 | doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/A%2bA/546/A69/table1&WDS=21441%2B2845 Vizier catalog entry] The primary,{{cite simbad|title = HR 8309|access-date = 13 January 2014}} with an apparent magnitude of 4.69, is an F-type main-sequence star with a stellar classification of F6V. It has 35% more mass than the Sun and 188% of the Sun's radius. The star is spinning with a projected rotational velocity of 9.6 km/s. The secondary companion,{{cite simbad|title = HR 8310|access-date = 13 January 2014}} with an apparent magnitude of 6.12, is a G-type main-sequence star with a class of G2V. It has a similar radius as the Sun and slightly more mass.

Two reported additional components, C (apparent magnitude 12.93) and D (apparent magnitude 6.94), are believed to be optical doubles rather than part of the Mu Cygni system. Component D is the more distant spectroscopic binary HD 206874 (HIP 107326), consisting of two early F-type subgiants.{{cite journal|bibcode=2009ApJS..180..117A|title=MK Classifications of Spectroscopic Binaries|journal=The Astrophysical Journal Supplement|volume=180|pages=117–118|last1=Abt|first1=Helmut A|year=2009|issue=1 |doi=10.1088/0067-0049/180/1/117|s2cid=122811461 }}