Upsilon-4 Eridani, a blue main-sequence star in Eridanus
Upsilon-4 Eridani is a blue main-sequence star in the constellation Eridanus. At 178 light years away, it is the 302nd brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.55.
Upsilon-4 Eridani (HIP 20042)
Upsilon-4 Eridani is a blue main-sequence star in the constellation Eridanus. At 178 light years away, it is the 302nd brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.55. Upsilon-4 Eridani is a multiple-star system. It is moving through the Galaxy at a speed of 24.1 km/s relative to the Sun and is part of the Tucana / Horologium moving group. Its projected Galactic orbit carries it between 21,300 and 24,300 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 2.70 from a distance of 120 light years.
Sky position: RA 4h 17.9m, Dec -33° 48'
Common designations: Upsilon-4 Eridani, 41 Eridani, HIP 20042, HD 27376
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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
| Rank | Mag. | Star |
| 7 | 3.56 | Phi Eridani |
| 8 | 3.69 | chi Eridani |
| 9 | 3.70 | Tau-4 Eridani |
| 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 Upsilon-4 Eridani
(compared to the Sun)
E
ccentricity: 6.4% vs. 16.0%Angle φ : 164.2°vs. 26.0°
Semi-major axis : 6,993 pc vs. 8,686 pc
Semi-minor axis: 6,979 pc vs. 8,574 pc
Focus-to-center
: 448 pcvs. 1,388 pcSemilatus rectum : 6,965 pc vs. 8,464 pc
Perigalacticon: 6,545 pc vs. 7,297 pc
Apogalacticon
: 7,441 pcvs. 10,074 pcSome Tabulated XHIP Data for Upsilon-4 Eridani
(see also: SIMBAD)
Astrometry
2007A&A...474..653V
| Position | Proper Motion | |
| Right Ascension: | 64.47341050° ±0.10 mas | 62.52 ±0.11 mas/yr. |
| Declination: | -33.79833154° ±0.13 mas | -7.24 ±0.16 mas/yr. |
| Galactic Longitude: | 234.67491499° | 13.58 mas/yr. |
| Galactic Latitude: | -45.47125477° | 61.46 mas/yr. |
Parallax: 18.33 ± 0.15 mas
Spectrography
Spectral Type: B6V 2009A&A...501..297Z.
Radial Velocity:
17.80 ±2.70 km/s [D rating]
2006AstL...32..759G.
This star is a spectroscopic binary with an unsolved orbit.
Iron Abundance [Fe/H]:
n/a
Photometry
band
magnitude
Abs. Mag.
U
B
3.44
-0.24
V
3.55
-0.13
R
I
3.63
-0.06
J
H
K
B-V: -0.11 V-I: -0.08
Derivations
Heliocentric distance: 54.55 pc (0.8% margin of error)
Galactocentric distance: 7,422 pc
Transverse velocity: 16.3 km/s
3D heliocentric position and motion:
|
toward: |
Galactic center | Galactic rotation | North Galactic Pole |
| Position ( X, Y, Z) | -22.1 pc | -31.2 pc | -38.9 pc |
| Velocity (U, V, W) | -10.9 km/s | -21.5 km/s | -1.5 km/s |