Tau-4 Eridani, a red giant star in Eridanus
Tau-4 Eridani is a red giant star in the constellation Eridanus. At 303 light years away, it is the 359th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.7.
Tau-4 Eridani (HIP 15474)
Tau-4 Eridani is a red giant star in the constellation Eridanus. At 303 light years away, it is the 359th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.70. Tau-4 Eridani is a multiple-star system. It is moving through the Galaxy at a speed of 49.3 km/s relative to the Sun. Its projected Galactic orbit carries it between 21,100 and 27,300 light years from the center of the Galaxy. It came closest to the Sun 1.6 million years ago when it had brightened to magnitude 2.34 from a distance of 162 light years.
Sky position: RA 3h 19.5m, Dec -21° 45.6'
Common designations: Tau-4 Eridani, 16 Eridani, HIP 15474, HD 20720
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Brightest stars in Eridanus:
(list all)
| Rank | Mag. | Star |
| 1 | 0.45 | Achernar |
| 2 | 2.78 | Cursa |
| 3 | 2.88 | Acamar |
| 4 | 2.97 | Zaurak |
| 5 | 3.52 | Rana |
| 6 | 3.55 | Upsilon-4 Eridani |
| 7 | 3.56 | Phi Eridani |
| 8 | 3.69 | chi Eridani |
9
| 3.70
) Tau-4 Eridani
| Rank | Mag. | Star |
| 10 | 3.72 | Epsilon Eridani |
| 11 | 3.81 | Theemim |
| 12 | 3.86 | Sceptrum |
| 13 | 3.89 | Azha |
| 14 | 3.93 | Nu Eridani |
| 15 | 3.97 | 43 Eridani |
| 16 | 4.01 | Mu Eridani |
| 17 | 4.04 | Beid |
Hover over other bright stars to identify or click to jump.
Galactic Orbit of Tau-4 Eridani
(compared to the Sun)
E
ccentricity: 12.8% vs. 16.0%Angle φ : -98.7°vs. 26.0°
Semi-major axis : 7,422 pc vs. 8,686 pc
Semi-minor axis: 7,361 pc vs. 8,574 pc
Focus-to-center
: 951 pcvs. 1,388 pcSemilatus rectum : 7,300 pc vs. 8,464 pc
Perigalacticon: 6,471 pc vs. 7,297 pc
Apogalacticon
: 8,374 pcvs. 10,074 pcSome Tabulated XHIP Data for Tau-4 Eridani
(see also: SIMBAD)
Astrometry
2007A&A...474..653V
| Position | Proper Motion | |
| Right Ascension: | 49.87904019° ±0.33 mas | 50.60 ±0.80 mas/yr. |
| Declination: | -21.75794250° ±0.35 mas | 31.60 ±0.80 mas/yr. |
| Galactic Longitude: | 212.08895427° | -15.79 mas/yr. |
| Galactic Latitude: | -55.99575397° | 57.53 mas/yr. |
Parallax: 10.71 ± 0.54 mas
Spectrography
Spectral Type: M3III-IIIa Ca-1 1989ApJS...71..245K.
Radial Velocity: 41.70 ±0.70 km/s [A rating] 2006AstL...32..759G.
Iron Abundance [Fe/H]:
n/a
Photometry
band
magnitude
Abs. Mag.
U
B
5.31
0.47
V
3.70
-1.14
R
I
1.50
-3.34
J
-0.19
-5.03
H
-0.98
-5.82
K
-1.12
-5.96
B-V: +1.61 V-I: +2.20
Derivations
Heliocentric distance: 93.09 pc (5.0% margin of error)
Galactocentric distance: 7,444 pc
Transverse velocity: 26.3 km/s
3D heliocentric position and motion:
|
toward: |
Galactic center | Galactic rotation | North Galactic Pole |
| Position ( X, Y, Z) | -44.1 pc | -27.7 pc | -77.2 pc |
| Velocity (U, V, W) | -41.3 km/s | -17.7 km/s | -20.4 km/s |