HR 7484
{{short description|Star in the constellation Cygnus}}
{{Starbox begin
| name = HR 7484
}}
{{Starbox image
| image = 250px
| caption = A light curve for V1143 Cygni, plotted from TESS data
}}
{{Starbox observe
| epoch = J2000
| dec = {{DEC|+54|58|25.6420}}
| appmag_v = {{Val|5.889|0.015}}, 6.37
| constell = Cygnus
}}
{{Starbox character
| class = F6V {{nowrap|(F5 V + F5 V)}}
| u-b =
| variable = Algol
}}
{{Starbox astrometry
| radial_v = {{Val|−13.9|0.2}}
| parallax = 24.7090
| p_error = 0.0422
}}
{{Starbox orbit
| primary =
| name =
| period_unitless = {{val|7.64075217|0.00000051|u=days}}
| axis =
| axis_unitless = {{Val|22.6950|ul=AU}}
| eccentricity = {{Val|0.5378|0.0003}}
| inclination = {{val|87.0|1.0}}
| node =
| periastron =
| periarg = {{Val|0.860|0.001}}
| periarg_primary =
| k1 = {{Val|88.02|0.05}}
| k2 = {{Val|89.97|0.10}}
}}
{{Starbox detail
| component1 = V1143 Cyg A
| mass = {{Val|1.356|0.003}}
| radius = {{Val|1.339|0.023}}
| luminosity = {{val|2.83|0.2}}
| gravity = {{Val|4.317|0.015}}
| temperature = {{Val|6450|100|fmt=commas}}
| metal_fe = 0.08
| rotational_velocity = {{val|18|3}}
| age_myr =
| component2 = V1143 Cyg B
| mass2 = {{Val|1.328|0.002}}
| radius2 = {{Val|1.316|0.023}}
| gravity2 = {{Val|4.323|0.015}}
| temperature2 = {{Val|6400|100|fmt=commas}}
| luminosity2 = {{val|2.65|0.2}}
| rotational_velocity2 = {{val|28|3}}
}}
{{Starbox catalog
| names = {{odlist | V=V1143 Cyg | HD=185912 | HIP=96620 | HR=7484 | SAO=31850 }}
}}
{{Starbox reference
| Simbad = HD+185912
}}
{{Starbox end}}
HR 7484 (V1143 Cyg) is a binary star system in the northern constellation of Cygnus. It is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.89. Based upon an annual parallax shift of 24.71, it is located 132 light years away. The system is moving closer with a heliocentric radial velocity of −14 km/s.
Observational history
Radial velocity measurements taken at the Dominion Astrophysical Observatory in Victoria, British Columbia Canada in 1919 led to the determination by William Edmund Harper that HR 7484 is a double-lined spectroscopic binary. The next year he published an orbit with a period of 7.6383 days as compared to the modern value of 7.64075217 days.
Physical characteristics
HR 7484 is a detached eclipsing binary, which means the orbital plane is aligned close to the line-of-sight from the Earth, causing the components to eclipse twice per orbit. The system is undergoing apsidal motion, with a rate greater than that predicted by general relativity. Both components are ordinary F-type main-sequence stars with similar physical properties. The star normally has an apparent magnitude of 5.89, but every 7.64 days (7 days, 15 hours, and 22 minutes) its brightness decreases to magnitude 6.37, approximately two thirds as bright. Five days and 17 hours after each primary eclipse, there is a secondary eclipse when the brightness drops to magnitude 6.06, about 85% of the normal brightness. Each eclipse lasts for 220 minutes. Both eclipses are partial.
References
{{reflist|refs=
{{cite simbad | title=HD 185912 | access-date=2018-07-14 }}
{{Cite Gaia DR2|2138551219835016320}}
| title=Relativistic apsidal motion in the eclipsing binary systems V1143 Cygni and EK Cephei
| last1=Gimenez | first1=A. | last2=Margrave | first2=T. E.
| journal=Astronomical Journal
| volume=90 | issue=2 | pages=358–363 | year=2005
| arxiv=astro-ph/0411788 | bibcode=1985AJ.....90..358G | bibcode-access=free | doi=10.1086/113740 | doi-access=free }}
| title=Fourth list of spectroscopic binaries
| display-authors=1 | last1=Plaskett | first1=J. S.
| last2=Harper | first2=W. E. | last3=Young | first3=R. K.
| journal=Journal of the Royal Astronomical Society of Canada
| year=1919 | volume=13 | pages=372–378
| bibcode=1919JRASC..13..372P | bibcode-access=free }}
{{cite journal | display-authors=1
| title=The Surface Brightness-color Relations Based on Eclipsing Binary Stars: Toward Precision Better than 1% in Angular Diameter Predictions
| last1=Graczyk | first1=Dariusz | last2=Konorski | first2=Piotr
| last3=Pietrzyński | first3=Grzegorz | last4=Gieren | first4=Wolfgang
| last5=Storm | first5=Jesper | last6=Nardetto | first6=Nicolas
| last7=Gallenne | first7=Alexandre | last8=Maxted | first8=Pierre F. L.
| last9=Kervella | first9=Pierre | last10=Kołaczkowski | first10=Zbigniew
| journal=The Astrophysical Journal | volume=837 | issue=1 | id=7 | pages=19 | date=March 2017
| arxiv=1611.09976 | bibcode=2017ApJ...837....7G | bibcode-access=free | doi=10.3847/1538-4357/aa5d56 | doi-access=free | s2cid=119004886
}}
| title=Photometric Observations and Apsidal Motion Study of V1143 Cyg
| display-authors=1 | last1=Dariush | first1=A.
| last2=Riazi | first2=N. | last3=Afroozeh | first3=A.
| journal=Astrophysics and Space Science
| volume=296 | issue=1–4 | pages=141–144 | date=April 2005
| arxiv=astro-ph/0411788 | bibcode=2005Ap&SS.296..141D | doi=10.1007/s10509-005-4416-0 | s2cid=119369053 }}
| title=XHIP: An extended hipparcos compilation
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}
}}
{{Stars of Cygnus}}
Category:F-type main-sequence stars
Category:Cygnus (constellation)