| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h38m 41.18316s[2] |
| Declination | +54° 58′ 25.6420″[2] |
| Apparent magnitude (V) | 5.889±0.015,[3] 6.37[4] |
| Characteristics | |
| Spectral type | F6V[5] (F5 V + F5 V)[3] |
| B−V color index | 0.482±0.004[5] |
| Variable type | Algol[4] |
| Astrometry | |
| Radial velocity (Rv) | −13.9±0.2[5] km/s |
| Proper motion (μ) | RA: +34.885[2] mas/yr Dec.: +162.839[2] mas/yr |
| Parallax (π) | 24.7090 ± 0.0422 mas[2] |
| Distance | 132.0 ± 0.2 ly (40.47 ± 0.07 pc) |
| Absolute magnitude (MV) | 2.83[5] |
| Orbit[3] | |
| Period (P) | 7.64075217±0.00000051 d[6] |
| Semi-major axis (a) | 22.6950 AU |
| Eccentricity (e) | 0.5378±0.0003 |
| Inclination (i) | 87.0±1.0° |
| Argument of periastron (ω) (secondary) | 0.860±0.001° |
| Semi-amplitude (K1) (primary) | 88.02±0.05 km/s |
| Semi-amplitude (K2) (secondary) | 89.97±0.10 km/s |
| Details[3] | |
| V1143 Cyg A | |
| Mass | 1.356±0.003 M☉ |
| Radius | 1.339±0.023 R☉ |
| Luminosity | 2.83±0.2[7] L☉ |
| Surface gravity (log g) | 4.317±0.015 cgs |
| Temperature | 6,450±100 K |
| Metallicity [Fe/H] | 0.08 dex |
| Rotational velocity (v sin i) | 18±3[7] km/s |
| V1143 Cyg B | |
| Mass | 1.328±0.002 M☉ |
| Radius | 1.316±0.023 R☉ |
| Luminosity | 2.65±0.2[7] L☉ |
| Surface gravity (log g) | 4.323±0.015 cgs |
| Temperature | 6,400±100 K |
| Rotational velocity (v sin i) | 28±3[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
HR 7484 (V1143 Cyg) is a binary star system in the northern constellationofCygnus. It is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.89.[3] Based upon an annual parallax shift of 24.71,[2] it is located 132 light years away. The system is moving closer with a heliocentric radial velocity of −14 km/s.[5]
Radial velocity measurements taken at the Dominion Astrophysical ObservatoryinVictoria, British Columbia Canada in 1919 led to the determination by William Edmund Harper that HR 7484 is a double-lined spectroscopic binary.[9] The next year he published an orbit with a period of 7.6383 days as compared to the modern value of 7.64075217 days.[10]
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.[11] The system is undergoing apsidal motion, with a rate greater than that predicted by general relativity.[11] Both components are ordinary F-type main-sequence stars with similar physical properties.[3] 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.[4] Both eclipses are partial.[7]
