V380 Cygni

V380 Cygni

A light curve for V380 Cygni, adapted from Tkachenko et al. (2012).[1] The blue points in the upper panel show Kepler data. The red line shows a model for the light curve which assumes the two stars have no intrinsic variability. The bottom panel shows the Kepler data with the model subtracted, revealing the intrinsic variability.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cassiopeia
Right ascension 19h 50m 37.32678s[2]
Declination +40° 35′ 59.1351″[2]
Apparent magnitude (V) 5.61 - 5.78[3]
Characteristics
Spectral type B1.5 II-III(primary) + B2 V(secondary)[4]
Variable type Algol / detached[3]
Astrometry
Proper motion (μ) RA: −3.125±0.055[2] mas/yr
Dec.: −8.067±0.053[2] mas/yr
Parallax (π)0.8673 ± 0.0510 mas[2]
Distance3,800 ± 200 ly
(1,150 ± 70 pc)
Orbit[5]
Period (P)12.425719±0.000014 d
Eccentricity (e)0.234±0.006
Inclination (i)82.4±0.02°
Semi-amplitude (K1)
(primary)		94.5±1.5 km/s
Semi-amplitude (K2)
(secondary)		151.1±3.0 km/s
Details
Primary
Mass11.80±0.13[1] M☉
Radius16.00±0.13[1] R☉
Luminosity54,200±2,700[1] L☉
Surface gravity (log g)3.102±0.007 cgs
Temperature21,500[1] K
Secondary
Mass7.194±0.055[1] M☉
Radius3.904±0.067[1] R☉
Luminosity3,000±320[1] L☉
Surface gravity (log g)4.112±0.015 cgs
Temperature22,000[1] K
Other designations
HD 187879, BD+40 3902, HIP 97634, HR 7567, SAO 48892,[6] Boss 5070
Database references
SIMBADdata

V380 Cygni is an eclipsing binary star in the constellation Cygnus, located about 3,800 light years away from the Earth. Its apparent magnitude ranges from 5.61 to 5.78, making it faintly visible to the naked eye of an observer located far from city lights.[3] Because it is an important test object for models of massive stars, it has been the subject of many scientific studies.[1]

V380 Cygni was discovered to be a spectroscopic binary by Walter Sydney Adams, based on three spectra taken on separate nights in 1912 at the Mount Wilson Observatory.[7][8] The binary's orbit was first calculated from spectra obtained in 1920 at the DDO; the period was found to be 12.427 days.[8] Because the physical separation of spectroscopic binaries is often relatively small, they are good candidates to be eclipsing binaries. For that reason, in 1923 Joel Stebbins included V380 Cygni (then called Boss 5070) in an early photo-electric photometry study. A secondary eclipse was detected in June 1923 on the first night the star was observed.[9][10]

V380 Cygni was observed several times at high cadence, for many days, by the Kepler space telescope. In addition to the brightness variations caused by eclipses, the Kepler data showed that the primary star has significant intrinsic variability which is most apt to be caused by gravity-mode oscillations.[1]

  1. ^ a b c d e f g h i j k Cite error: The named reference Tkachenko2012 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference dr3 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Hill1984 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Guinan2000 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Adams1914 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Harper1920 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Stebbins1928 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Kron1935 was invoked but never defined (see the help page).