Theemin — Star in Eridanus
HIP 21393; Upsilon2 Eridani; 52 Eridani
About Theemin
Description
Theemin, Upsilon-2 Eridani, is a yellow giant of spectral class G8+ III about 214 light-years away. It shines at magnitude 3.82 and has a mass of about 2.5 Suns. Theemin is a slow rotator with relatively sharp spectral lines — evidence of ongoing spin-down as the star has evolved from a faster-rotating main-sequence progenitor.
Observing Tips
Theemin lies in the central part of Eridanus, south of Epsilon Eri. Binoculars show its warm yellow color. Best observed October through February.
History
The name Theemin comes from the Arabic "al-thumām," a pre-Islamic asterism name of uncertain precise meaning — possibly related to "hair ribbons" or "grasses." The IAU adopted the name in 2017.
Fun Facts
Upsilon-2 Eri's pairing with the more westerly Upsilon Eri marks another of the chain of bright stars tracing Eridanus southward. Binoculars trace the full length of the celestial river through many such signpost stars.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Medium+ | 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
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
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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