Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cepheus |
Right ascension | 21h 37m 55.22469s [1] |
Declination | +62° 04′ 54.9825″ [1] |
Apparent magnitude (V) | 4.69 - 4.78 [2] |
Characteristics | |
Spectral type | B2 Ib [3] |
U−B color index | −0.54 [4] |
B−V color index | +0.30 [4] |
Variable type | α Cyg [2] |
Astrometry | |
Radial velocity (Rv) | −13.50 ± 0.8 [5] km/s |
Proper motion (μ) | RA: −1.64 ± 0.17 [1] mas/yr Dec.: −3.02 ± 0.16 [1] mas/yr |
Parallax (π) | 0.00 ± 0.17 mas [1] |
Distance | 950 [6] pc |
Absolute magnitude (MV) | −6.44 [3] |
Details | |
Searle et al 2008 [3] | |
Mass | 21 M☉ |
Radius | 39.8 R☉ |
Luminosity | 151,000 L☉ |
Surface gravity (log g) | 2.50 cgs |
Temperature | 18,000 K |
Rotational velocity (v sin i) | 73 km/s |
Markova & Puls 2008 [7] | |
Mass | 12 M☉ |
Radius | 32 R☉ |
Luminosity | 129,000 L☉ |
Surface gravity (log g) | 2.50 cgs |
Temperature | 19,200 K |
Rotational velocity (v sin i) | 45 km/s |
Other designations | |
Database references | |
SIMBAD | data |
9 Cephei (9 Cep), also known as V337 Cephei, is a variable star in the constellation Cepheus.
9 Cephei was given the name V337 Cephei and classified as an α Cygni variable in 1967. [9] It varies irregularly between magnitude 4.69 and 4.78. [2] A study of the Hipparcos satellite photometry showed an amplitude of 0.56 magnitudes, but could find no periodicity. [10]
9 Cephei is considered to be a member of the Cepheus OB2 stellar association, a scattering of massive bright stars around a thousand parsecs away in the southern part of the constellation Cepheus. [3]
Calculations of the physical properties of 9 Cephei vary considerably even from broadly similar observational data. Modelling using the non-LTE line-blanketed CMFGEN atmospheric code gives a temperature of 18,000 K, radius of 40 R☉, luminosity of 151,000 L☉, and mass of 21 M☉. [3] Calculations using the FASTWIND model give gives a temperature of 19,200 K, radius of 32 R☉, luminosity of 129,000 L☉, and mass of 12 M☉. [7]
Kappa Cassiopeiae is a star in the constellation Cassiopeia.
Zeta Cephei is a star in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Joppa (Ethiopia). It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.
Nu Cephei is a class A2, fourth-magnitude supergiant star in the constellation Cepheus. It is a white pulsating α Cygni variable star located about 4,700 light-years from Earth.
NO Aurigae is a pulsating variable star in the constellation Auriga. It is an unusually-luminous asymptotic giant branch star about 3,500 light years away.
HD 123657, or BY Boötis, is a variable star of magnitude 4.98–5.33V. This makes it a dim naked eye star. The star is located near the end of the handle of the Big Dipper, but just within the boundaries of the constellation Boötes.
6 Cassiopeiae is a white hypergiant in the constellation Cassiopeia, and a small-amplitude variable star.
V381 Cephei is a triple star system in the northern constellation of Cepheus. Its apparent magnitude is slightly variable between 5.5 and 5.7.
55 Cygni is a blue supergiant star in the constellation Cygnus. It is thought to be a member of the Cygnus OB7 stellar association at about 2,700 light years.
V424 Lacertae is a red supergiant variable star in the constellation Lacerta. It is a member of the Lacerta OB1 stellar association.
19 Monocerotis is a single, variable star in the equatorial constellation of Monoceros, located approximately 1,220 light years away from the Sun based on parallax. It has the variable star designation V637 Monocerotis, while 19 Monocerotis is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.00. It is receding from the Earth with a heliocentric radial velocity of +25 km/s.
Sigma Ophiuchi, Latinized from σ Ophiuchi, is a single, orange-hued star in the equatorial constellation Ophiuchus. Its apparent visual magnitude is 4.31, which is bright enough to be faintly visible to the naked eye. The annual parallax shift of 3.62 mas as seen from Earth provides a distance estimate of roughly 900 light years. It is moving closer to the Sun with a radial velocity of −28 km/s.
KQ Puppis is a spectroscopic binary variable star in the constellation Puppis. A red supergiant star and a hot main sequence star orbit each other every 9,742 days. Its apparent magnitude varies between 4.82 and 5.17.
V1073 Scorpii is a variable star in the constellation Scorpius. It has a non-Greek Bayer designation of k Scorpii. The star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around +4.87. Parallax measurements yield a distance estimate of approximately 2,920 ly (896 pc) from the Sun, and it is drifting further away with a radial velocity of +7 km/s. It has an absolute magnitude of −6.8
9 Persei is a single variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; 9 Persei is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.2. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s. The star is a member of the Perseus OB1 association of co-moving stars.
10 Persei is a blue supergiant star in the constellation Perseus. Its apparent magnitude is 6.26 although it is slightly variable.
TV Geminorum is a variable red supergiant in the constellation Gemini. Its visual magnitude varies from 6.3 to 7.5.
V419 Cephei is an irregular variable star in the constellation of Cepheus with an apparent magnitude that varies between 6.54 and 6.89.
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.
U Lacertae is a spectroscopic binary star in the constellation Lacerta.
WR 86 is a visual binary in the constellation Scorpius consisting of a Wolf-Rayet star and a β Cephei variable. It lies 2° west of NGC 6357 on the edge of the Great Rift in the Milky Way in the tail of the Scorpion.