Star profile
21 Eridani
What is 21 Eridani
21 Eridani is an orange K-type star only 110 light-years away, among the nearest in its Flamsteed listing within the long river winding from Orion southward. Cooler than the Sun, its light left around 1916, in the depths of the First World War. Eridanus is an enormously extended constellation; this star sits in its northernmost reach, the easiest stretch to follow from European latitudes.
Where it is and when to see it
21 Eridani lies in the southern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is November, when it culminates around midnight.
- From London it culminates about 33° above the horizon.
- From New York it culminates about 44° above the horizon.
- From Sydney it culminates about 62° above the horizon.
It can be seen from anywhere south of 84° N.
It ranks no. 126 in brightness among the 129 stars of Eridanus in our catalogue. To find it, start from Achernar, the brightest: it lies about 57° away (a fist at arm's length covers about 10°).
The light you see today left it about 110 years ago.
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Astronomical data for 21 Eridani
- Constellation
- Eridanus
- Apparent magnitude
- 5.97
- Distance
- 109.9 light years
- Coordinates (J2000)
- RA 54.755° · Dec -5.626°
- Catalogue
- HIP 17027 · HD 22713
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Other stars in Eridanus
Eridanus has 129 stars in Stelvia's catalogue. Here are a few of them.
- AchernarAlpha Eridani0.45
- CursaBeta Eridani2.78
- AcamarTheta 1 Eridani2.88
- HIP 199965.95
- HIP 208925.95
- HIP 210425.95
- 55 Eridani5.98
- HIP 183395.99