OY Carinae

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OY Carinae
Observation data
Epoch {{{epoch}}}      Equinox
Constellation Carina
Right ascension 10h 06m 22.07s
Declination −70° 14′ 04.6″
Apparent magnitude (V) +12.2
Spectral type DA / M6V
Distance 277.1 ly
(85[1] pc)
Mass ≈0.7[1]/0.07[2] M
Radius 0.011[1]/0.127[2] R
Luminosity 0.0055/0.00117 L
Temperature 15,000/3,000 K
Period (P) 0.000172 yr
Semi-major axis (a) 0.00213 Astronomical Units"
Eccentricity (e) 0.0
Inclination (i) 83.3°
Other designations
OY Car, RX J1006.5-7014, SON 6302, 2MASS J10062206-7014045, SBC9 600, AAVSO 1004-69
Database references

OY Carinae (abbreviated OY Car) is an eclipsing binary system approximately 277 light-years away from the Sun, classed as cataclysmic variable. The system comprises an eclipsing white dwarf and red dwarf that orbit each other every 1.51 hours, and possibly a yet unconfirmed third low-mass (substellar?) companion.

Planetary system?[edit]

Greenhill et al. (2009) would invoke the presence of a third object to explain orbital period variations with an apparent periodicity of roughly 35 years. The third body could yield a minimum mass 7 times greater than Jupiter and be located 9.5 Astronomical Units away from the cataclysmic variable system,[3] being likely either a massive planetary object or else a very low-mass brown dwarf. It is likely that the apparent change is due to solar-cycle type magnetic activity in the secondary star. Large irregular deviations from the general trend, with time-scales of years, also occur. Further observations will be able to confirm either discard the presence of a substellar companion.

The OY Carinae planetary system[3]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b (unconfirmed) ≥7 MJ 9.5 35±3.5  ?

See also[edit]


  1. ^ a b c Mauche & Raymond (2000). "The EUV Emission-Line spectrum of OY Carinae in superoutburst: scattering in the wind" (PDF). RevMexAA (Serie de Conferencias). 9: 232–233. 
  2. ^ a b Wood; Horne, Keith; Berriman, Graham; Wade, Richard A. (1989). "Eclipse studies of the dwarf nova OY Carinae in quiescence". Astrophysical Journal. 341: 974–994. Bibcode:1989ApJ...341..974W. doi:10.1086/167557. 
  3. ^ a b Greenhill; Hill, K. M.; Dieters, S.; Fienberg, K.; et al. (2006). "Decrease in the orbital period of dwarf nova OY Carinae". Monthly Notices of the Royal Astronomical Society. 372 (3): 1129–1132. arXiv:astro-ph/0602331free to read. Bibcode:2006MNRAS.372.1129G. doi:10.1111/j.1365-2966.2006.10920.x. 

Coordinates: Sky map 10h 06m 22.07s, −70° 14′ 04.6″