Tau Orionis, a blue subgiant star in Orion
Tau Orionis is a blue subgiant star in the constellation Orion. At 494 light years away, it is the 318th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.59.
Tau Orionis (HIP 24674)
Tau Orionis is a blue subgiant star in the constellation Orion. At 494 light years away, it is the 318th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.59. Tau Orionis is the primary component of a multiple-star system. It is moving through the Galaxy at a speed of 23.6 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,500 and 30,000 light years from the center of the Galaxy. It came closest to the Sun 5.3 million years ago when it had brightened to magnitude 2.19 from a distance of 259 light years.
Sky position: RA 5h 17.6m, Dec -6° 50.4'
Common designations: Tau Orionis, 20 Orionis, HIP 24674, HD 34503
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Brightest stars in Orion:
(list all)
| Rank | Mag. | Star |
| 3 | 1.64 | Bellatrix |
| 4 | 1.69 | Alnilam |
| 5 | 1.74 | Alnitak |
| 6 | 2.07 | Saiph |
| 7 | 2.25 | Mintaka |
| 8 | 2.75 | Hatsya |
| 9 | 3.19 | Tabit |
| 10 | 3.35 | Eta Orionis |
| 11 | 3.39 | Heka |
12
| 3.59
) Tau Orionis
| Rank | Mag. | Star |
| 13 | 3.68 | Pi-4 Orionis |
| 14 | 3.71 | Pi-5 Orionis |
| 15 | 3.77 | Sigma Orionis |
| 16 | 4.06 | Omicron-2 Orionis |
| 17 | 4.09 | Phi-2 Orionis |
| 18 | 4.12 | Mu Orionis |
| 19 | 4.13 | 29 Orionis |
Hover over other bright stars to identify or click to jump.
Galactic Orbit of Tau Orionis
(compared to the Sun)
E
ccentricity: 10.1% vs. 16.0%Angle φ : 11.4°vs. 26.0°
Semi-major axis : 8,350 pc vs. 8,686 pc
Semi-minor axis: 8,307 pc vs. 8,574 pc
Focus-to-center
: 841 pcvs. 1,388 pcSemilatus rectum : 8,265 pc vs. 8,464 pc
Perigalacticon: 7,509 pc vs. 7,297 pc
Apogalacticon
: 9,191 pcvs. 10,074 pcSome Tabulated XHIP Data for Tau Orionis
(see also: SIMBAD)
Astrometry
2007A&A...474..653V
| Position | Proper Motion | |
| Right Ascension: | 79.40166213° ±0.13 mas | -15.30 ±0.50 mas/yr. |
| Declination: | -6.84438593° ±0.09 mas | -8.00 ±0.50 mas/yr. |
| Galactic Longitude: | 208.27714637° | 0.27 mas/yr. |
| Galactic Latitude: | -23.95990073° | -17.26 mas/yr. |
Parallax: 6.60 ± 0.15 mas
Spectrography
Spectral Type: B6IV 2009A&A...501..297Z.
Radial Velocity: 20.10 ±2.70 km/s [A rating] 2006AstL...32..759G.
Iron Abundance [Fe/H]:
n/a
Photometry
band
magnitude
Abs. Mag.
U
3.01
-2.89
B
3.48
-2.43
V
3.59
-2.31
R
I
3.68
-2.23
J
H
K
B-V: -0.11 V-I: -0.09
Derivations
Heliocentric distance: 151.42 pc (2.3% margin of error)
Galactocentric distance: 7,522 pc
Transverse velocity: 12.4 km/s
3D heliocentric position and motion:
|
toward: |
Galactic center | Galactic rotation | North Galactic Pole |
| Position ( X, Y, Z) | -121.9 pc | -65.6 pc | -61.5 pc |
| Velocity (U, V, W) | -11.7 km/s | -6.5 km/s | -19.5 km/s |