OU Geminorum

OU Geminorum (OU Gem) is a visual binary or possible triple star located in the constellation of Gemini.

OU Geminorum
Observation data
Epoch 2000      Equinox 2000
Constellation Gemini
Right ascension  06h 26m 10.2464s[1]
Declination +18° 45 24.896[1]
Apparent magnitude (V) 6.768[2]
Characteristics
Spectral type K3Vk[2]
U−B color index 0.662[2]
B−V color index 0.972[2]
Variable type BY Dra
Astrometry
Radial velocity (Rv)−8.98±0.10[3] km/s
Proper motion (μ) RA: −124.020±0.097[1] mas/yr
Dec.: −159.335±0.054[1] mas/yr
Parallax (π)68.46 ± 0.34[1] mas
Distance47.6 ± 0.2 ly
(14.61 ± 0.07 pc)
Absolute magnitude (MV)5.93±0.05[2]
Orbit[3]
PrimaryOU Gem Aa
CompanionOU Gem Ab
Period (P)6.991878±0.000004 d
Eccentricity (e)0.151±0.0024
Periastron epoch (T)54900.0719±0.0203 JD
Argument of periastron (ω)
(secondary)
77.63±1.09°
Semi-amplitude (K1)
(primary)
57.09±0.15 km/s
Semi-amplitude (K2)
(secondary)
66.22±0.28 km/s
Details[4]
OU Gem Aa
Mass0.85 M
Radius0.81 R
Surface gravity (log g)4.55 cgs
Temperature4960 K
OU Gem Ab
Mass0.71 M
Radius0.65 R
Surface gravity (log g)4.65 cgs
Temperature4390 K
Other designations
OU Gem, BD+18 1214, GJ 233, HD 45088, HIP 30630, SAO 95677.[5]
Database references
SIMBADdata

The system has an absolute magnitude of 5.93, so at a distance of 48 light years it has an apparent magnitude of 6.77 when viewed from earth. It also has a total Proper Motion of 0.210"/yr and belongs to the Ursa Major stream.

The system is a much studied BY Draconis variable star with a period of 6.99 days[6] The primary star has a spectral type of K3Vk. The secondary star in the system has a surface temperature of 4486±50 K and orbits the primary in about seven days.[7][8]

References

  1. Brown, A. G. A.; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy and Astrophysics. 595. A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. hdl:2445/125903.Gaia Data Release 1 catalog entry
  2. Koen, C.; et al. (April 2010), "UBV(RI)C JHK observations of Hipparcos-selected nearby stars", Monthly Notices of the Royal Astronomical Society, 403 (4): 1949–1968, Bibcode:2010MNRAS.403.1949K, doi:10.1111/j.1365-2966.2009.16182.x.
  3. Glazunova, L. V.; et al. (2014). "Absolute parameters and chemical composition of the binary star OU Gem". Monthly Notices of the Royal Astronomical Society. 444 (2): 1901–1908. Bibcode:2014MNRAS.444.1901G. doi:10.1093/mnras/stu1576.
  4. Fuhrmann, Klaus (2008). "Nearby stars of the Galactic disc and halo - IV". Monthly Notices of the Royal Astronomical Society. 384 (1): 173–224. Bibcode:2008MNRAS.384..173F. doi:10.1111/j.1365-2966.2007.12671.x.
  5. "V* OU Gem". SIMBAD. Centre de données astronomiques de Strasbourg.
  6. Bopp, B. W. (1980). "HD 45088 as a BY Draconis variable". Publications of the Astronomical Society of the Pacific. 92: 218–220. Bibcode:1980PASP...92..218B. doi:10.1086/130651.
  7. "Aricns 4C00500".
  8. "Multiwavelength optical observations of chromospherically active bina…" (PDF).


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