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]

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]
Characteristics
Spectral type G8.6 III[3]
U−B color index 0.63[2]
B−V color index 0.88[2]
Astrometry
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 mas[1]
Distance680 ± 70 ly
(210 ± 20 pc)
Absolute magnitude (MV)−0.3±0.2[4]
Orbit[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)
(secondary)
61.9±1.3°
Semi-amplitude (K1)
(primary)
5.55±0.04 km/s
Details
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
SIMBADdata

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]

References

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  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. S2CID 18759600. 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. S2CID 118505114.
  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.