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Epsilon Capricorni — Star in Capricornus

Magnitude 4.4–4.7m Star Capricornus (Cap) Visible
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1Physical Properties

Magnitude 4.68
Range 4.48 - 4.72
Variable Type Gamma Cassiopeiae (Eruptive Be Star)
Spectral Type B2.5Vpe
Star Color Blue (B-V -0.17)

2Position & Identifiers

RA 21h 37m 04.8s
Dec -19° 27' 58.0"
Constellation Capricornus (Cap)
HR 8260
HIP 106723
HD 205637
SAO 164520
Bayer Epsilon
Flamsteed 39 Cap
Variable ID Eps Cap
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Medium+ Medium Hard+
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 Jul – Sep (peak: Aug)

5Survey Image

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6

Size Comparison

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7

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8

Spectral Classification

9

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
10

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

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14Stellar Notes

Gamma Cas 4.44 - 4.72V. Polarization variable. Slight variation in H alpha line width.
Component A is SB, 5.0, 6.3v, 0.0047"; component B, 9.5v K1III-IV: at 68", physical, vsini =<54k/s.
Shell star. Shell spectrum resembles supergiant A-type with vsini 50k/s. Also classified B3IIIe.

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.

M30
NGC 7099
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 7.5 3.8° Capricornus
NGC 7180
Hard+
Elliptical galaxy
Galaxy mag 12.5 6.0° Aquarius
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