Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 20h 52m 3.57718s [2] |
Declination | +34° 39′ 27.4861″ [2] |
Apparent magnitude (V) | 7.3 - 7.9 [3] |
Characteristics | |
Primary | |
Spectral type | O9.5V [4] |
Apparent magnitude (U) | 5.91[ citation needed ] |
Apparent magnitude (B) | 6.996[ citation needed ] |
Apparent magnitude (V) | 7.287 [4] |
U−B color index | −1.086 [4] |
B−V color index | −0.291 [4] |
Secondary | |
Spectral type | O9.5V [4] |
Apparent magnitude (U) | 5.883[ citation needed ] |
Apparent magnitude (B) | 6.974[ citation needed ] |
Apparent magnitude (V) | 7.265 [4] |
U−B color index | −1.091 [4] |
B−V color index | −0.291 [4] |
Variable type | Algol [3] |
Astrometry | |
Proper motion (μ) | RA: +2.763 [2] mas/yr Dec.: −15.981 [2] mas/yr |
Parallax (π) | 0.6759 ± 0.0338 mas [2] |
Distance | 4,900 ly (1,500 [4] pc) |
Absolute magnitude (MV) | −3.59/−3.62 [4] |
Absolute bolometric magnitude (Mbol) | −6.65±0.04/−6.7±0.04 [4] |
Orbit [4] | |
Primary | Y Cyg A |
Companion | Y Cyg B |
Period (P) | 2.99633210±0.00000031 d |
Semi-major axis (a) | 28.72 R☉ |
Eccentricity (e) | 0.14508 |
Inclination (i) | 86.474±0.019° |
Periastron epoch (T) | 2,446,308.66407±0.0001 |
Argument of periastron (ω) (secondary) | 312.514° |
Argument of periastron (ω) (primary) | 132.514±0.052° |
Details [4] | |
Primary | |
Mass | 17.72±0.35 M☉ |
Radius | 5.785±0.091 R☉ |
Luminosity | 36,000 L☉ |
Surface gravity (log g) | 4.161±0.014 cgs |
Temperature | 33,200±200 K |
Rotational velocity (v sin i) | 132 km/s |
Age | 2 Myr |
Secondary | |
Mass | 17.73±0.3 M☉ |
Radius | 5.816±0.063 R☉ |
Luminosity | 37,700 L☉ |
Surface gravity (log g) | 4.157±0.01 cgs |
Temperature | 33,521±40 K |
Rotational velocity (v sin i) | 132 km/s |
Age | 2 Myr |
Other designations | |
Database references | |
SIMBAD | data |
Y Cygni is an eclipsing and double-lined spectroscopic binary star system in the constellation of Cygnus. It is located about 4,900 light-years from Earth. The system was one of the first binaries with a convincing detection of the apsidal precession. [4]
The two stars, being O-type main-sequence stars, orbit each other with a period of nearly 3 days. [4]
The early type of Y Cyg made it a popular target for astronomers in the past, and spectroscopic orbits have been historically computed numerous times. [5] The first of these studies was published in 1920 by John Stanley Plaskett. [6] Extensive spectroscopic studies of Y Cyg were carried out as early as 1930. [7] Several follow-ups to these have been published in 1959, [8] 1971, [9] [10] and 1980. [11] The latter of these contained an estimate of the period of apsidal precession.
V1500 Cygni or Nova Cygni 1975 was a bright nova occurring in 1975 in the constellation Cygnus. It had the second highest intrinsic brightness of any nova of the 20th century, exceeded only by CP Puppis in 1942.
74 Aquarii is a triple star system in the constellation of Aquarius. 74 Aquarii is its Flamsteed designation and it also bears the variable star designation HI Aquarii. The combined apparent visual magnitude is 5.8, although it is very slightly variable, and it is located at a distance of 590 light-years from Earth.
Delta Cygni is a binary star of a combined third-magnitude in the constellation of Cygnus. It is also part of the Northern Cross asterism whose brightest star is Deneb. Based upon parallax measurements obtained during the Hipparcos mission, Delta Cygni is located roughly 165 light-years distant from the Sun.
Gamma Persei is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system is of roughly 221 light-years with a 1% margin of error. About 4° to the north of Gamma Persei is the radiance point for the annual Perseid meteor shower.
EZ Canis Majoris is binary system in the constellation of Canis Major. The primary is a Wolf-Rayet star and it is one of the ten brightest Wolf-Rayet stars, brighter than apparent magnitude 7.
32 Cygni is a binary star system in the Cygnus constellation. It is a 4th magnitude star, which can be seen with the naked eye under suitably dark skies. Parallax measurements give an estimated distance of 1,000 light-years (307 parsecs) from the Earth. However, Schröder et al. (2007) suggest the actual value, after correcting for Malmquist bias, may be closer to 1,174 light-years (360 parsecs). Although it is a spectrsocopic binary with components that cannot be separated visually, it has two entries in the Henry Draper Catalogue, with identical magnitudes and positions, but showing the spectral types of the two components.
HR Carinae is a luminous blue variable star located in the constellation Carina. It is surrounded by a vast nebula of ejected nuclear-processed material because this star has a multiple shell expanding atmosphere. This star is among the most luminous stars in the Milky Way. It has very broad emission wings on the Balmer lines, reminiscent from the broad lines observed in the spectra of O and Wolf–Rayet stars. A distance of 5 kpc and a bolometric magnitude of −9.4 put HR Car among the most luminous stars of the galaxy.
SS Cygni is a variable star in the northern constellation Cygnus. It was discovered in 1896 by Louisa D. Wells, a computer working under Edward Pickering at Harvard College Observatory. It is the prototype of the subclass of dwarf novae that show only normal eruptions. It typically rises from 12th magnitude to 8th magnitude for 1–2 days every 7 or 8 weeks. The northerly declination of SS Cygni makes the star almost circumpolar from European and North American latitudes, allowing a large proportion of the world's amateur astronomers to monitor its behavior. Furthermore, since the star lies against the rich backdrop of the Milky Way band, the telescope field of view around SS Cygni contains an abundance of useful brightness comparison stars.
Lambda Cygni is a class B5V star in the constellation Cygnus. Its apparent magnitude is 4.54 and it is approximately 770 light years away based on parallax.
47 Cygni is a triple star system in the northern constellation of Cygnus, and is located around 4,000 light years from the Earth. It is visible to the naked eye with a combined apparent visual magnitude of 4.61. The system is moving closer to the Earth with a heliocentric radial velocity of −4.6 km/s.
1 Geminorum is a star in the constellation Gemini. Its apparent magnitude is 4.15.
31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, ο2 Cygni or V695 Cygni, is a ternary star system about 750 light years away in the constellation Cygnus.
ZZ Boötis is a star system in the constellation Boötes. It varies from magnitude 6.79 to 7.44 over five days. Based on its parallax, measured by the Gaia spacecraft, it is about 350 light-years away.
CD Crucis, also known as HD 311884, is an eclipsing binary star system in the constellation Crux. It is around 14,000 light years away near the faint open cluster Hogg 15. The binary contains a Wolf–Rayet star and is also known as WR 47.
AC Herculis, is an RV Tauri variable and spectroscopic binary star in the constellation of Hercules. It varies in brightness between apparent magnitudes 6.85 and 9.0.
BC Cygni is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.
BI Cygni(BI Cyg, IRC +40408, BD+36 4025) is a red supergiant in the constellation Cygnus. It is an irregular variable star with a maximum brightness of magnitude 8.4 and a minimum of magnitude 9.9. It is considered a member of the Cygnus OB1 stellar association, its distance is around 1,300 parsecs (4,200 ly) of the Solar System. It is less than a degree south of another variable red supergiant, BC Cygni.
Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.6, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.
HR 7484 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.
CH Cygni is a red giant, variable, symbiotic binary in the constellation Cygnus. It is the nearest symbiotic star to Earth, and one of the brightest, making it an ideal candidate for study.