57 Cygni

57 Cygni
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 20h 53m 14.75503s[1]
Declination +44° 23′ 14.1408″[1]
Apparent magnitude (V) 4.80[2]
Characteristics
Spectral type B5 V[3]
B−V color index −0.134±0.006[2]
Astrometry
Radial velocity (Rv)−21.1±2.8[2] km/s
Proper motion (μ) RA: +11.94[1] mas/yr
Dec.: −2.08[1] mas/yr
Parallax (π)6.21 ± 0.22 mas[1]
Distance530 ± 20 ly
(161 ± 6 pc)
Absolute magnitude (MV)−1.23[2]
Orbit[4]
Period (P)2.8548 days
Eccentricity (e)0.139±0.014[5]
Inclination (i)≈ 48[6]°
Periastron epoch (T)2441571.275 JD
Argument of periastron (ω)
(secondary)		159.6°
Semi-amplitude (K1)
(primary)		111.9 km/s
Semi-amplitude (K2)
(secondary)		126.0 km/s
Details
57 Cyg A
Mass5.54±0.55[5] M☉
Radius3.3±0.4[4] R☉
Temperature17,190[7] K
Rotational velocity (v sin i)40[8] km/s
57 Cyg B
Mass4.92±0.49[5] M☉
Radius2.9±0.4[4] R☉
Rotational velocity (v sin i)30[8] km/s
Other designations
57 Cyg, BD+43°3755, HD 199081, HIP 103089, HR 8001, SAO 50180[9]
Database references
SIMBADdata

57 Cygni is a close binary star[4] system in the constellation Cygnus, located about 530 light years from Earth. It is visible to the naked eye as a blue-white hued star with a baseline apparent visual magnitude of 4.80.[2] The pair have a magnitude difference of 0.34.[4] This system is moving closer to the Earth with a heliocentric radial velocity of −21 km/s.[2]

This is a double-lined spectroscopic binary with an orbital period of 2.85 days and an eccentricity of 0.15.[4] They show a steady change in their longitude of periastron, showing an apsidal period of 203±4 years.[10] The system does not form an eclipsing binary, having the orbital inclination of around 48°.[6] Both components are B-type main-sequence stars with a stellar classification of B5 V.[4]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Lesh1968 was invoked but never defined (see the help page).
  4. ^ a b c d e f g Cite error: The named reference Hilditch1973 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference DeLaurentis2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Jetsu1999 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Zorec2009 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Abt2002 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Tapia1979 was invoked but never defined (see the help page).