Delta Circini
Delta Circini (δ Cir), is a multiple star system located in the constellation Circinus. Delta Circini is also known as HR 5664, and HD 135240. The system has a combined apparent visual magnitude of +5.09, and is located at a distance of about 700 pc (2,300ly) from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Circinus |
| Right ascension | 15h 16m 56.89591s |
| Declination | −60° 57′ 26.1201″ |
| Apparent magnitude (V) | 5.09 (5.05 - 5.20) |
| Characteristics | |
| Spectral type | O7.5III(f) (O8IV + O9.5V + B0.5V() |
| U−B color index | −0.88 |
| B−V color index | −0.06 |
| Variable type | Eclipsing and ellipsoidal |
| Astrometry | |
| Radial velocity (Rv) | −17.80 km/s |
| Proper motion (μ) | RA: −4.085 mas/yr Dec.: −3.758 mas/yr |
| Parallax (π) | 1.4345 ± 0.1231 mas |
| Distance | 2,300 ± 200 ly (700 ± 60 pc) |
| Orbit | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 3.902463 days |
| Semi-major axis (a) | 34.7 R☉ |
| Eccentricity (e) | 0.068 |
| Inclination (i) | 75.81° |
| Semi-amplitude (K1) (primary) | 156.8 km/s |
| Semi-amplitude (K2) (secondary) | 280.4 km/s |
| Orbit | |
| Primary | Aab |
| Companion | Ac |
| Period (P) | 1,644 days |
| Semi-major axis (a) | 3.87″ |
| Eccentricity (e) | 0.415 |
| Inclination (i) | 87.7° |
| Semi-amplitude (K1) (primary) | 23.6 km/s |
| Details | |
| Aa | |
| Mass | 20.00±0.50 M☉ |
| Radius | 9.256±0.091 R☉ |
| Luminosity | 153,000+27,000 −23,000 L☉ |
| Surface gravity (log g) | 3.806 cgs |
| Temperature | 37,500 K |
| Rotational velocity (v sin i) | 150±9 km/s |
| Ab | |
| Mass | 11.41±0.24 M☉ |
| Radius | 5.326±0.091 R☉ |
| Luminosity | 21,827+5,026 −4,085 L☉ |
| Surface gravity (log g) | 4.043±0.014 cgs |
| Temperature | 30,400±400 K |
| Rotational velocity (v sin i) | 141±230 km/s |
| Ac | |
| Mass | 18.7 M☉ |
| Luminosity | 17,000 L☉ |
| Surface gravity (log g) | 4.2 cgs |
| Temperature | 28,000 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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