Mintaka
Mintaka /ˈmɪntəkə/, designation Delta Orionis (δ Orionis, abbreviated Delta Ori, δ Ori) and 34 Orionis (34 Ori), is a multiple star system some 1,200 light-years from the Sun in the constellation of Orion. Together with Alnitak (Zeta Orionis) and Alnilam (Epsilon Orionis), the three stars form Orion's Belt, known by many names among ancient cultures. The star is located very close to the celestial equator. When Orion is near the meridian, Mintaka is the rightmost of the Belt's stars when viewed from the Northern Hemisphere facing south.
Orion's Belt (composed of the three brightest stars shown), Mintaka being the rightmost, on the west side | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| δ Ori A (Aa1 + Aa2 + Ab) | |
| Right ascension | 05h 32m 00.40009s |
| Declination | −00° 17′ 56.7424″ |
| Apparent magnitude (V) | 2.23 (2.50 + 3.90) |
| δ Ori B | |
| Right ascension | 05h 31m 58.745s |
| Declination | −00° 18′ 18.65″ |
| Apparent magnitude (V) | 14.0 |
| HD 36485 | |
| Right ascension | 05h 32m 00.406s |
| Declination | −00° 17′ 04.38″ |
| Apparent magnitude (V) | 6.85 |
| Characteristics | |
| A | |
| Spectral type | O9.5II + B1V +B0IV |
| U−B color index | −1.05 |
| B−V color index | −0.22 |
| Variable type | Eclipsing binary |
| C | |
| Spectral type | B3V + A0V |
| U−B color index | −0.71 |
| B−V color index | −0.16 |
| Astrometry | |
| Radial velocity (Rv) | 18.50±0.5 km/s |
| Proper motion (μ) | RA: 0.64±0.56 mas/yr Dec.: −0.69±0.27 mas/yr |
| Parallax (π) | 4.71 ± 0.58 mas |
| Distance | 1,200 ly (380 pc) |
| Absolute magnitude (MV) | −5.8 |
| δ Ori Aa1 | |
| Absolute magnitude (MV) | −5.4 |
| δ Ori Aa2 | |
| Absolute magnitude (MV) | −2.9 |
| δ Ori Ab | |
| Absolute magnitude (MV) | −4.2 |
| HD 36485 | |
| Proper motion (μ) | RA: +1.523 mas/yr Dec.: −1.653 mas/yr |
| Parallax (π) | 2.6245 ± 0.0538 mas |
| Distance | 1,240 ± 30 ly (381 ± 8 pc) |
| Orbit | |
| Primary | δ Ori Aa1 |
| Companion | δ Ori Aa2 |
| Period (P) | 5.732436 days |
| Semi-major axis (a) | 43.1±1.7 R☉ |
| Eccentricity (e) | 0.1133±0.0003 |
| Inclination (i) | 76.5±0.2° |
| Periastron epoch (T) | 2,456,295.674±0.062 |
| Argument of periastron (ω) (secondary) | 141.3±0.2° |
| Orbit | |
| Primary | δ Ori Aa1/2 |
| Companion | δ Ori Ab |
| Period (P) | 53,839 days |
| Semi-major axis (a) | 20,038 R☉ |
| Eccentricity (e) | 0.5886±0.016 |
| Inclination (i) | 104.7±0.4° |
| Longitude of the node (Ω) | 122.4±0.5° |
| Periastron epoch (T) | 2,458,773.2±0.1 |
| Argument of periastron (ω) (secondary) | 259±2° |
| Details | |
| δ Ori Aa1 | |
| Mass | 24 M☉ |
| Radius | 16.5 R☉ |
| Luminosity | 190,000 L☉ |
| Surface gravity (log g) | 3.37±0.15 cgs |
| Temperature | 29,500±500 K |
| Rotational velocity (v sin i) | 130±10 km/s |
| δ Ori Aa2 | |
| Mass | 8.4 M☉ |
| Radius | 6.5 R☉ |
| Luminosity | 16,000 L☉ |
| Surface gravity (log g) | 3.9 cgs |
| Temperature | 25,600±3,000 K |
| Rotational velocity (v sin i) | 150±50 km/s |
| δ Ori Ab | |
| Mass | 22.5 M☉ |
| Radius | 10.4 R☉ |
| Luminosity | 63,000 L☉ |
| Surface gravity (log g) | 3.5±0.3 cgs |
| Temperature | 28,400±1,500 K |
| Rotational velocity (v sin i) | 220±20 km/s |
| δ Ori B | |
| Radius | 0.77 R☉ |
| Luminosity | 0.431 L☉ |
| Temperature | 5,324 K |
| HD 36485 | |
| Mass | 6-11 M☉ |
| Radius | 5.7 R☉ |
| Luminosity | 3,300 L☉ |
| Surface gravity (log g) | 4.41 cgs |
| Temperature | 18,400 K |
| Other designations | |
| Mintaka Aa: HD 36486, HR 1851, SAO 132220/132221, BD−00°983, GC 6847 | |
| Mintaka Ab: δ Orionis B, CCDM J05320-0018D, WDS J05320-0018Ab | |
| δ Ori B: UCAC3 180-24383, CCDM J05320-0018B, WDS J05320-0018B | |
| HD 36485: δ Orionis C, HR 1851, SAO 132221, BD−00°982, GC 6848, PLX 1261, CCDM J05320-0018C | |
| Database references | |
| SIMBAD | data |
| δ Ori B | |
| HD 36485 | |
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