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BU Circini — Star in Circinus

Magnitude 6.1m Star Circinus (Cir) Visible
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1Physical Properties

Magnitude 6.10
Variable Type Beta Cephei (Pulsating)
Spectral Type B2III giant
Star Color Blue-white (B-V -0.06)

2Position & Identifiers

RA 14h 45m 10.9s
Dec -55° 36' 07.0"
Constellation Circinus (Cir)
HR 5488
HIP 72121
HD 129557
SAO 241971
Variable ID BU Cir
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Hard+ Hard V. 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 Mar – May (peak: Apr)

5Survey Image

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6

Size Comparison

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7

Compare Stars

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

Beta C, amp. 0.04u, 0.03y, 0.04V, 0.131d with possible secondary periods.
In Norma dark cloud.
Var. 0.135d, amp. about 18k/s.

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 5749
Easy
Open cluster
Open Cluster mag 9.0 1.2° Lupus
V Cen
Medium+
Pulsating variable, period 5.5d
Variable Star mag 6.93 2.2° Centaurus
Rigil Kentaurus
HIP 71681; Alpha1 Centauri
Easy
Easy double, sep 9.4″
Double Star mag -0.01 5.3° Centaurus
NGC 5927
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 8.3 8.1° Lupus
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