HR 8442

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HR 8442
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cepheus
Right ascension  22h 07m 09.634s[1]
Declination +58° 50′ 26.58″[1]
Apparent magnitude (V) 6.32[2]
Spectral type G8.6 III[3]
U−B color index 0.63[2]
B−V color index 0.88[2]
Radial velocity (Rv)−7.37±0.03[4] km/s
Proper motion (μ) RA: −16.09±0.41[1] mas/yr
Dec.: −22.30±0.41[1] mas/yr
Parallax (π)4.80 ± 0.46[1] mas
Distance680 ± 70 ly
(210 ± 20 pc)
Absolute magnitude (MV)−0.3±0.2[4]
PrimaryHR 8442A
CompanionHR 8442B
Period (P)737.4±0.4 days
Eccentricity (e)0.308±0.007
Periastron epoch (T)54113.3±2.1
Argument of periastron (ω)
Semi-amplitude (K1)
5.55±0.04 km/s
Mass2.97[5] M
Temperature5261±40[5] K
Age0.35[5] Gyr
Other designations
BD+58 2393, FK5 3770, HD 210220, HIP 109190, HR 8442, SAO 34072
Database references

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.[4]

The spectroscopic binary nature of the star was first noticed by Jose Renan de Medeiros and Michel Mayor using radial velocity measurements from the Coravel spectrometer at Haute-Provence Observatory.[6] Roger griffin then placed the star on his observing program at Cambridge Observatory leading to an orbital solution being published in 2015.[4]


  1. ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. ^ a b c Argue, A. N. (1966). "UBV photometry of 550 F, G and K type stars". Monthly Notices of the Royal Astronomical Society. 133 (4): 175–493. Bibcode:1966MNRAS.133..475A. doi:10.1093/mnras/133.4.475.
  3. ^ Gray, David F. (1989). "The rotational break for G giants". Astrophysical Journal. 347: 1021–1029. Bibcode:1989ApJ...347.1021G. doi:10.1086/168192.
  4. ^ a b c d e Griffin, R. F. (2015). "Spectroscopic binary orbits from photoelectric radial velocities. Paper 241: HR 1884, HD 174103, HD 182563, and HR 8442, with a note on zeta Cephei". The Observatory. 135: 71–95. Bibcode:2015Obs...135...71G.
  5. ^ a b c Luck, R. Earle (2015). "Abundances in the Local Region. I. G and K Giants". Astronomical Journal. 150 (3). 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88.
  6. ^ de Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement. 139 (3): 433–460. arXiv:astro-ph/0608248. Bibcode:1999A&AS..139..433D. doi:10.1051/aas:1999401.