| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22 07 09.634 |
| Declination | +58° 50′ 26.58″ |
| Apparent magnitude (V) | 6.32 |
| Characteristics | |
| Spectral type | G8.6 III |
| U−B color index | 0.63 |
| B−V color index | 0.88 |
| Astrometry | |
| Radial velocity (Rv) | −7.37±0.03 km/s |
| Proper motion (μ) | RA: −16.09±0.41 mas/yr Dec.: −22.30±0.41 mas/yr |
| Parallax (π) | 4.80 ± 0.46 mas |
| Distance | 680 ± 70 ly (210 ± 20 pc) |
| Absolute magnitude (MV) | −0.3±0.2 |
| Orbit | |
| Primary | HR 8442A |
| Companion | HR 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 | |
| Mass | 2.97 M☉ |
| Temperature | 5261±40 K |
| Age | 0.35 Gyr |
| Other designations | |
| BD+58 2393, FK5 3770, HD 210220, HIP 109190, HR 8442, SAO 34072 | |
| Database references | |
| SIMBAD | data |
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.
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. Roger Griffin then placed the star on his observing program at Cambridge Observatory leading to an orbital solution being published in 2015.
References
- ^ 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
- ^ 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.
- Gray, David F. (1989). "The rotational break for G giants". Astrophysical Journal. 347: 1021–1029. Bibcode:1989ApJ...347.1021G. doi:10.1086/168192.
- ^ 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.
- ^ 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.
- 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.
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