Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cepheus |
Right ascension | 20h 45m 21.12879s [1] |
Declination | +57° 34′ 47.0080″ [1] |
Apparent magnitude (V) | 4.51 [2] |
Characteristics | |
Spectral type | F8IV-V + F9IV-V [2] |
Astrometry | |
Radial velocity (Rv) | −32.82±0.04 [3] km/s |
Proper motion (μ) | RA: −62.32 [1] mas/yr Dec.: −236.00 [1] mas/yr |
Parallax (π) | 36.64 ± 0.48 mas [1] |
Distance | 89 ± 1 ly (27.3 ± 0.4 pc) |
Absolute magnitude (MV) | 2.35 [4] |
Orbit [2] | |
Period (P) | 494.16±0.58 d |
Semi-major axis (a) | 0.065±0.001" (≥50.2±0.5 Gm [5] ) |
Eccentricity (e) | 0.551±0.004 |
Inclination (i) | 24.53±3.13° |
Longitude of the node (Ω) | 325.21±1.05° |
Periastron epoch (T) | B 1996.335 ± 0.0017 |
Argument of periastron (ω) (secondary) | 68.86±0.76° |
Details [2] | |
HR 7955 A | |
Mass | 1.071±0.037 M☉ |
Age | 2.25 [6] Gyr |
HR 7955 B | |
Mass | 1.047±0.037 M☉ |
Other designations | |
Database references | |
SIMBAD | data |
HR 7955 is a binary star [2] system in the northern circumpolar constellation of Cepheus, near the constellation border with Cygnus. It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.51. [2] The system is located at a distance of 89 light-years (27.3 parsecs) from the Sun, based on parallax. [1] It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.243 arc seconds per annum, [8] and is drifting closer to the Sun with a radial velocity of -33 km/s. [3]
The double-lined nature of this spectroscopic binary system was not announced until 1972. [5] It has an orbital period of 1.35 years and an eccentricity of 0.551. [2] Both components appear to be slightly evolved stars that are leaving the main sequence and becoming subgiant stars, with stellar classifications of F8IV-V and F9IV-V. They each have slightly greater mass than the Sun: 107% and 105%, respectively. [2] The system is about 2.25 billion years old. [6]
Beta Scuti, Latinized from β Scuti, is a binary star system in the southern constellation Scutum. Based upon an annual parallax shift of 3.56 mas as seen from Earth, it is located approximately 920 light years from the Sun. The primary component has an apparent visual magnitude of +4.22 and is radiating about 1,270 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 4,622 K. This yellow-hued star is a G-type bright giant with a stellar classification of G4 IIa.
Rho Tucanae is a binary star system in the southern constellation of Tucana. It is visible to the naked eye with a combined apparent visual magnitude of +5.38. Based upon an annual parallax shift of 24.37 mas as seen from Earth, it is located 131 light years from the Sun.
HD 40979 is a triple star system in the northern constellation of Auriga. The combined brightness of this group lies below the typical limit of visibility to the naked eye at an apparent visual magnitude of 6.74. It is located at a distance of approximately 108 light years from the Sun based on parallax. The system is receding with a radial velocity of +32 km/s. It has a relatively high rate of proper motion, traversing the celestial sphere at the rate of 0.182″ per year.
Xi Cassiopeiae is a blue-white hued binary star system in the northern constellation of Cassiopeia. It has an apparent visual magnitude of +4.81 and thus is faintly visible to the naked eye. Based upon an annual parallax shift of 2.28 mas as seen from Earth, this system is located roughly 1,400 light years from the Sun. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.20 due to interstellar dust. It is advancing in the general direction of the Sun with a radial velocity of roughly −10.6 km/s.
Upsilon2 Centauri is a binary star system in the southern constellation Centaurus. It is visible to the naked eye with an apparent visual magnitude of +4.33. Based upon an annual parallax shift of just 2.57 mas as seen from Earth, this star is located roughly 1,300 light years from the Sun. Relative to its neighbors, the system has a peculiar velocity of 39.2+8.8
−15.2 km/s and it may form a runaway star system.
HD 176051 is a spectroscopic binary star system approximately 49 light years away from Earth in the constellation Lyra. The pair orbit with a period of 22,423 days and an eccentricity of 0.25. Compared to the Sun, they have a somewhat lower proportion of elements more massive than helium. Their individual masses are estimated at 1.07 and 0.71 solar masses (M☉). The system is moving closer to the Sun with a radial velocity of −47 km/s and will reach perihelion in about 269,000 years when it comes within roughly 17 ly (5.1 pc) of the Sun.
HD 178911 is a triple star system with an exoplanetary companion in the northern constellation of Lyra. With a combined apparent visual magnitude of 6.70, it is a challenge to view with the naked eye. The system is located at a distance of approximately 161 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −38 km/s.
HD 34790 is a double-lined spectroscopic binary star system in the northern constellation of Auriga. It has a combined apparent magnitude of 5.66, which means it is faintly visible to the naked eye. Based upon observations by the Hipparcos satellite, it is located around 289 light years away. It has a combined stellar classification of A1Vs, matching that of an A-type main sequence star, and shines with 35 times the luminosity of the Sun.
HD 129132 is a triple star system in the northern constellation of Boötes. It is dimly visible to the naked eye with a combined apparent visual magnitude of 6.13. The distance to this system is approximately 382 light years based on parallax, and it is drifting further away from the Sun with a radial velocity of +1.7 km/s.
HD 125040 is a visual binary star system in the northern constellation of Boötes. It appears as a dim point of light near the lower limit of perception with the naked eye, having a combined apparent visual magnitude of 6.25. The system is located at a distance of approximately 106 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −7 km/s. It has a high proper motion, traversing the celestial sphere at an angular rate of 0.164 arcseconds yr−1.
Theta Draconis, a name Latinized from θ Draconis, is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye at night with an apparent visual magnitude of 4.12. Parallax measurements place it at an estimated distance of 68.6 light-years from the Sun, and it is drifting closer with a radial velocity of −8 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.464″ per year. O. J. Eggen included this star as a member of the NGC 1901 supercluster based on its space motion.
Xi Orionis is a binary star system in the northeastern part of the constellation of Orion, well above the red giant star Betelgeuse in the sky. It lies next to another blue main-sequence star, Nu Orionis, which is somewhat closer at 520 light-years' distance. The apparent visual magnitude of Xi Orionis is 4.47, which is bright enough to be seen with the naked eye. The distance to this star, as determined using the parallax method, is roughly 610 light-years.
Phi Cygni, Latinized from φ Cygni, is a binary star system in the northern constellation of Cygnus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The annual parallax shift is 12.25 mas as measured from Earth, which yields a distance estimate of around 266 light years. It is moving further from the Sun with a radial velocity of +4.5 km/s.
μ Cygni, Latinised as Mu Cygni, is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.49. The system is located 72 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +17 km/s.
Epsilon Librae is the Bayer designation for a binary star system in the zodiac constellation Libra. With an apparent visual magnitude of 4.922, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 32.02 mas, it is located about 102 light years away from the Sun.
38 Leonis Minoris is a binary star system in the northern constellation of Leo Minor. It shines with a combined light of apparent magnitude 5.84, which indicates it a dimly visible to the naked eye under good viewing conditions. An annual parallax shift of 19.11 mas provides a distance estimate of around 171 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.226 arcseconds per year, and is moving away from the Sun with a radial velocity of +31 km/s.
HR 8442 is a spectroscopic binary star in the constellation Cepheus. The primary is a G type giant star while the secondary's spectral type is unknown.
HD 163840 is a binary star system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 6.45, which falls just below the brightness level that is visible to the naked eye for people with normal eyesight. An annual parallax shift of 35.40 mas provides a distance estimate of about 92 light years. The system is moving closer to the Sun with a radial velocity of −33 km/s. In about 769,000 years, it will make perihelion at a separation of around 27.2 ly (8.33 pc).
34 Pegasi is a triple star system in the northern constellation of Pegasus. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.76. The system is located at a distance of 131 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −13.5 km/s. It has been catalogued as a member of the Hyades Supercluster, although its membership status remains doubtful.
HD 3443 is a binary system composed of medium-mass main sequence stars in the constellation of Cetus about 50 light years away.