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Mu Crucis — Star in Crux

Mu Cru (BS4899)

Star Crux (Cru) Visible
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1Physical Properties

Magnitude 5.17
Range 4.99 - 5.18
Variable Type Gamma Cassiopeiae (Eruptive Be Star)
Spectral Type B5Vne
Star Color Blue-white (B-V -0.12)

2Position & Identifiers

RA 12h 54m 36.8s
Dec -57° 10' 06.0"
Constellation Crux (Cru)
HR 4899
HIP 63005
HD 112091
Bayer Mu
Variable ID Mu2 Cru
SIMBAD Wikipedia

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Medium Hard+ 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 Feb – Apr (peak: Mar)

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5

Size Comparison

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6

Compare Stars

7

Spectral Classification

8

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
9

Stellar Lifecycle

10

Blackbody Spectrum

11

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

12

Stellar Fusion

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13Stellar Notes

Gamma Cas 4.99 - 5.18V.
CPM with HR 4898.
Sco-Cen assoc.; probable member of Sco-Cen cluster; member of Pleiades group.

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.

Mu Cru
Mu Cru (BS4898)
Easy
Easy double, sep 34.5″
Double Star mag 4.03 0.0° Crux
S Cru
Medium
Pulsating variable, period 4.7d
Variable Star mag 6.58 1.3° Crux
NGC 4852
Easy
Open cluster
Open Cluster mag 9.0 2.5° Centaurus
Coalsack Nebula
Easy
Dark nebula — shows as a void against the Milky Way
Dark Nebula mag 12.0 5.9° Crux
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Crux
Mythology, bright stars, and deep-sky highlights.
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