![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/Orion_constellation_map.svg/640px-Orion_constellation_map.svg.png&w=640&q=50)
Iota Orionis
Multiple star system in the constellation Orion / From Wikipedia, the free encyclopedia
Iota Orionis (ι Orionis, abbreviated ι Ori) is a multiple star system in the equatorial constellation of Orion the hunter. It is the eighth-brightest member of Orion with an apparent visual magnitude of 2.77 and also the brightest member of the asterism known as Orion's Sword. It is a member of the NGC 1980 open cluster. From parallax measurements, it is located at a distance of roughly 1,340 light-years (412 parsecs) from the Sun.
Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Orion |
Right ascension | 05h 35m 25.98191s[1] |
Declination | –05° 54′ 35.6435″[1] |
Apparent magnitude (V) | 2.77[2] |
Characteristics | |
ι Orionis A | |
Spectral type | O9 III + B0.8 III/IV[3] + B2:IV:[4] |
U−B color index | –1.08[2] |
B−V color index | –0.24[2] |
ι Orionis B | |
Spectral type | B8 III[5] |
Variable type | Orion[6] |
Astrometry | |
ι Orionis A | |
Radial velocity (Rv) | 21.5[7] km/s |
Proper motion (μ) | RA: +1.42[1] mas/yr Dec.: –0.46[1] mas/yr |
Parallax (π) | 1.40 ± 0.22 mas[1] |
Distance | 412+14 −13[4] pc |
Orbit[3][8] | |
Primary | ι Orionis Aa1 |
Companion | ι Orionis Aa2 |
Period (P) | 29.1338 days |
Semi-major axis (a) | 132 R☉ |
Eccentricity (e) | 0.764 |
Inclination (i) | ~60° |
Periastron epoch (T) | 2,450,072.80 HJD |
Details | |
ι Ori Aa1 | |
Mass | 23.1[8] M☉ |
Radius | 8.3[8] R☉ |
Luminosity | 68,000[8] L☉ |
Surface gravity (log g) | 3.73[3] cgs |
Temperature | 32,500[3] K |
Metallicity [Fe/H] | +0.10[9] dex |
Rotational velocity (v sin i) | 122[10] km/s |
Age | 4.0–5.5[3] Myr |
ι Ori Aa2 | |
Mass | 13.1[8] M☉ |
Radius | 5.4[8] R☉ |
Luminosity | 8,630[8] L☉ |
Surface gravity (log g) | 3.78[3] cgs |
Temperature | 27,000[3] K |
Age | 9.4 ± 1.5[3] Myr |
ι Ori B | |
Mass | 5.12[11] M☉ |
Surface gravity (log g) | 4.0[9] cgs |
Temperature | 18,000[9] K |
Age | ~3[9] Myr |
Other designations | |
ι Ori A: 44 Orionis, HD 37043, HIP 26241, HR 1899, 2MASS J05352597-0554357 | |
ι Ori B: V2451 Ori, 2MASS J05352645-0554445 | |
ι Ori C: 2MASS J05352920-0554471 | |
Database references | |
SIMBAD | ι Ori |
ι Ori B | |
ι Ori C |
Close
The system has three visible components designated Iota Orionis A, B and C. Iota Orionis A has also been resolved using speckle interferometry and is also a massive spectroscopic binary, with components Iota Orionis Aa1 (officially named Hatysa /hɑːˈtiːsə/), Aa2, and Ab.