Upsilon Eridani — Star in Eridanus
HIP 20042; Upsilon4 Eridani; 41 Eridani
About Upsilon Eri
Description
Upsilon Eridani is a B-type main-sequence star of spectral class B6 V about 178 light-years away in the central part of the long celestial river Eridanus. It shines at magnitude 3.56 with a crisp blue-white color. Upsilon Eri is a classical Be-type candidate, with occasional weak hydrogen emission observed in spectra.
Observing Tips
Upsilon Eri lies in the middle part of Eridanus, the long constellation winding south from Rigel. It is an easy naked-eye star. Best observed October through February.
History
Upsilon Eri retains its Bayer designation in current IAU catalogs.
Fun Facts
Eridanus is one of the longest constellations by sky extent, winding about 60 degrees from near Orion down to Achernar at the celestial south pole. Upsilon Eri is a useful waypoint in tracing the full extent of the celestial river.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
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Explore
6
Size Comparison
7
Compare Stars
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Spectral Classification
9
Hertzsprung-Russell Diagram
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Stellar Lifecycle
11
Blackbody Spectrum
12
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
13
Stellar Fusion
Discover
14Stellar Notes
15
Light Travel Time Machine
16
Relativistic Travel
Survey Image
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Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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