Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cepheus |
Right ascension | 21h 19m 15.682s [1] |
Declination | +58° 37′ 24.550″ [1] |
Apparent magnitude (V) | 5.51 - 5.71 [2] |
Characteristics | |
Spectral type | M1epIb + B [3] |
U−B color index | 0.00 [4] |
B−V color index | +1.34 [4] |
Variable type | Lc [2] |
Astrometry | |
Radial velocity (Rv) | −14.10 [5] km/s |
Proper motion (μ) | RA: −1.435 [6] mas/yr Dec.: −5.427 [6] mas/yr |
Parallax (π) | 1.59 ± 0.23 mas [6] |
Distance | approx. 2,100 ly (approx. 630 pc) |
Absolute magnitude (MV) | −5.2 [7] |
Details | |
Aa | |
Mass | 7.2 [8] - 16 [9] M☉ |
Radius | 977 [10] R☉ |
Luminosity | 178,000 [10] L☉ |
Temperature | 3,745±170 [1] [10] K |
Ab | |
Mass | 13 [9] M☉ |
B | |
Mass | 7.1 [11] M☉ |
Radius | 3.4 [12] R☉ |
Luminosity | 1,487 [12] L☉ |
Surface gravity (log g) | 4.18 [12] cgs |
Temperature | 19,965 [12] K |
Metallicity [Fe/H] | −0.30 [11] dex |
Rotational velocity (v sin i) | 42.8 [13] km/s |
Age | 49.1 [8] Myr |
Other designations | |
A: HD 203338 | |
B: HD 203339 | |
Database references | |
A | |
B |
V381 Cephei (HR 8164) is a triple star system in the northern constellation of Cepheus. Its apparent magnitude is slightly variable between 5.5 and 5.7.
V381 Cephei is a visual double star with components A and B separated by 4.6". The primary is HD 203338 and the secondary is the magnitude 9.2 HD 203339. [9]
HD 203338 is itself a spectroscopic binary with components Aa and Ab orbiting every 280 years. [9] It forms a VV Cephei-type binary system with a hot companion which is accreting mass from the primary. The long period means that it exhibits fewer peculiarities than other VV Cephei binaries. [14]
Component Aa is a red supergiant and its close companion is a B2 main sequence star. The supergiant is a pulsating variable with a small amplitude and poorly defined period. It is generally given spectral class qualifiers indicating peculiarities and emission, which may be associated with the disc around the hot secondary. [14]
Component B, HD 203339, is a B3 main sequence star with a mass around 11 M☉. [9]
Cepheus is a constellation in the deep northern sky, named after Cepheus, a king of Aethiopia in Greek mythology. It is one of the 48 constellations listed by the second century astronomer Ptolemy, and it remains one of the 88 constellations in the modern times.
Mu Cephei, also known as Herschel's Garnet Star, Erakis, or HD 206936, is a red supergiant or hypergiant star in the constellation Cepheus. It appears garnet red and is located at the edge of the IC 1396 nebula. Since 1943, the spectrum of this star has served as a spectral standard by which other stars are classified.
Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 2,500 light years based on spectroscopic measurements. It is drifting further away with a radial velocity of +42 km/s.
VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus. It is both a B[e] star and shell star.
Nu Caeli is a yellow-white hued star in the constellation Caelum. It has an apparent visual magnitude of 6.07, which indicates it is near the lower limit on brightness that is visible to the naked eye. According to the Bortle scale, the star can be viewed from dark suburban skies. Based upon an annual parallax shift of 20.3 mas as seen from Earth, this star is located 161 light years from the Sun.
KW Sagittarii is a red supergiant star, located approximately 2,420 parsecs away from the Sun in the direction of the constellation Sagittarius. It is one of the largest known stars, with a diameter about 1,000 times larger than the Sun. If placed at the center of the Solar System, the star's surface would engulf Mars, coming close to Jupiter's orbit.
V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 13,000 light-years away from the Sun. It has an estimated radius of 1,139 solar radii. If it were placed in the center of the Solar System, it would extend to between the orbits of Mars and Jupiter.
Zeta Cephei is a red supergiant star, located about 1000 light-years away in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Ethiopia. It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.
W Cephei is a spectroscopic binary and variable star located in the constellation Cepheus. It is thought to be a member of the Cep OB1 stellar association at about 8,000 light years. The supergiant primary star is one of the largest known stars and as well as one of the most luminous red supergiants.
13 Vulpeculae is a blue giant with a stellar classification of class B9.5III in the northern constellation Vulpecula. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.57 and it is approximately 339 light years away from the Sun based on parallax. The star is radiating 180 times the luminosity of the Sun from its photosphere at an effective temperature of 8,801 K.
15 Vulpeculae is a variable star in the northern constellation of Vulpecula, located approximately 243 light years away based on parallax. It has the variable star designation NT Vulpeculae; 15 Vulpeculae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a typical apparent visual magnitude of 4.66. This object is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.
HD 204521 is a star in the northern constellation of Cepheus. In the sky it positioned just to the west of the magnitude 3.2 star Beta Cephei. This object has a yellow hue similar to the Sun but is too faint to be visible to the naked eye with an apparent visual magnitude of 7.26. It is located at a distance of 86 light years from the Sun based on parallax, and has an absolute magnitude of 5.15. The star is drifting closer with a radial velocity of −77 km/s, and is predicted to come to within 7.96 light-years in 334,000 years. At that distance the star can have a relatively small perturbing effect on comets in the Oort cloud.
HD 102839 is a class G6Ib star in the constellation Musca. Its apparent magnitude is 4.98 and it is approximately 1,550 light years away from Earth based on parallax.
1 Puppis is a single star in the southern constellation of Puppis. It lies in the northern part of the constellation at a distance of about 790 ly, east of Aludra in Canis Major and just north of the white supergiant, 3 Puppis. This object is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of 4.59. It is moving further from the Earth with a heliocentric radial velocity of +32.4 km/s.
HD 59890 is a class G3Ib yellow supergiant star in the constellation Puppis. Its apparent magnitude is 4.65 and it is approximately 1,360 light years away based on parallax.
KQ Puppis is a spectroscopic binary located about 2,700 light-years from Earth in the constellation Puppis. A red supergiant star and a B-type main-sequence star orbit each other every 27 years. Its apparent magnitude varies between 4.82 and 5.17, making it faintly visible to the naked eye.
HD 54893, often called A Puppis is a suspected variable star in the constellation Puppis. Its apparent magnitude is 4.83 and is approximately 860 light years away based on parallax.
HDE 316285 is a blue supergiant star in the constellation Sagittarius. It is a candidate luminous blue variable and lies about 6,000 light years away in the direction of the Galactic Center.
36 Camelopardalis is a single star in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.3. Parallax measurements provide a distance estimate of approximately 710 light years away from the Sun, and it is drifting away from the Earth with a radial velocity of −1.15 km/s.
HD 33541, also known as HR 1683, is a white-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.83, making it faintly visible to the naked eye. Gaia DR3 parallax measurements imply a distance of 358 light years and it is currently receding with a heliocentric radial velocity of 9.9 km/s. At its current distance HD 33541's brightness is diminished by 0.16 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.58.