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Nu Eridani — Star in Eridanus

Magnitude 3.9–4.0m Star Eridanus (Eri) Visible
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1Physical Properties

Magnitude 3.93
Range 3.87 - 4.01
Period 4.2 hours
Variable Type Beta Cephei (Pulsating)
Spectral Type B2IV subgiant
Star Color Blue (B-V -0.21)
Distance 674 ly

2Position & Identifiers

RA 04h 36m 19.1s
Dec -03° 21' 09.0"
Constellation Eridanus (Eri)
HR 1463
HIP 21444
HD 29248
SAO 131346
Bayer Nu
Flamsteed 48 Eri
Variable ID Nu Eri
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Easy Medium+ Medium
50mm finder Easy Easy Easy
150mm scope Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Oct – Dec (peak: Nov)

5Survey Image

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7

Size Comparison

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8

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9

Spectral Classification

10

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
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

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15Stellar Notes

Beta C 3.4 - 3.60p, 0.17790414d, changing. Probable interference periods 0.1779 and 0.1735d with beat period of | 7.0256d. Possibly also E, 103.9d.
Ori OB1.
0.19d.
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.

NGC 1622
Hard+
Edge-on galaxy
Galaxy mag 12.3 0.2° Eridanus
NGC 1788
Medium+
Reflection nebula around a bright star
Reflection Nebula mag 5.80 7.6° Orion
66 Eri
Medium
Variable star, range 5.1–5.6
Variable Star mag 5.12 7.7° Eridanus
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