| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Mensa |
| Right ascension | 04h 52m 15.678s[1] |
| Declination | −70° 14′ 31.33″[1] |
| Apparent magnitude (V) | 15.317[2] |
| Characteristics | |
| Spectral type | F7Ib + G4II[3][a] |
| Apparent magnitude (J) | 13.727[1] |
| Apparent magnitude (H) | 13.217[1] |
| Apparent magnitude (K) | 13.262[1] |
| Variable type | Eclipsing binary, δ Cep[4] |
| Astrometry | |
| Distance | 163,000[5] ly (50,000 pc) |
| Orbit[3] | |
| Period (P) | 309.404±0.002 days |
| Semi-major axis (a) | 389.86±0.77 |
| Eccentricity (e) | 0.1659±0.0006 |
| Inclination (i) | 86.833±0.016° |
| Argument of periastron (ω) (secondary) | 342.0±0.6° |
| Details[3][a] | |
| A (Cepheid) | |
| Mass | 4.165±0.032 M☉ |
| Radius | 34.92±0.34 R☉ |
| Luminosity | 1,439 L☉ |
| Surface gravity (log g) | 1.971±0.011 cgs |
| Temperature | 6,050±160 K |
| B | |
| Mass | 4.134±0.037 M☉ |
| Radius | 44.85±0.29 R☉ |
| Surface gravity (log g) | 1.751±0.010 cgs |
| Temperature | 5,120±130 K |
| Rotational velocity (v sin i) | 11.1±1.2 km/s |
| Other designations | |
2MASS J04521567-7014313 | |
| Database references | |
| SIMBAD | data |
OGLE-LMC-CEP0227 is an eclipsing binary and Cepheid variable star,[6] pulsating every 3.8 days.[4] The star, in the Large Magellanic Cloud, was the first Cepheid star system found to be orbiting exactly edge on.[4]
The OGLE-LMC-CEP0227 system contains two stars which orbit each other almost exactly 'edge on' to the line of sight from the Earth. This unique configuration has allowed astronomers to refine their understanding of classical Cepheid variable stars. Studies of this system have allowed astronomers to measure the Cepheid mass with unprecedented accuracy. There is still disagreement over whether the pulsational properties accurately match the mass derived from the observed orbit.[4][6]
The two stars orbit each other every 309 days, and each has a mass close to 4.1 M☉. The primary component has an effective temperature of 6,050 K and the secondary a temperature of 5,120 K.[3]
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