HR 7955

Last updated
HR 7955
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
BD+57°2240, FK5  782, GJ  9706, HD  198084, HIP  102431, HR  7955, SAO  32862 [7]
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]

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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.

References

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  5. 1 2 Griffin, R. F. (October 1999), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 148: HR 7955", The Observatory, 119: 272–283, Bibcode:1999Obs...119..272G
  6. 1 2 Luck, R. Earle (January 2017), "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants", The Astronomical Journal, 153 (1): 19, arXiv: 1611.02897 , Bibcode:2017AJ....153...21L, doi:10.3847/1538-3881/153/1/21, S2CID   119511744, 21.
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  8. Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv: astro-ph/0412070 . Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID   2603568.