Aludra
HIP 35904; Eta CMa; 31 CMa
Observable Double Star
Good (48/100)
Sep: 177.0", Companion: mag 6.8
HIP 35904; Eta CMa; 31 CMa
DoubleStar
CMa
Visible
Level 2
Small telescope (4") - Requires steady seeing
Physical Properties
Magnitude
2.45
Spectral Type
B5Ia
Star Color
Blue-white
(B-V -0.08)
Distance
1988.8 ly
Position & Identifiers
RA
07h 24m 05.7s
Dec
-29° 18' 11.0"
Constellation
CMa
HR
2827
HIP
35904
Bayer
Eta
Flamsteed
31 CMa
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Visibility
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Multiple Star System
Separation
177.0″
Companion Mag
6.8
Position Angle
287°
Star Colors
A: Blue-white
B: Yellow
Discoverer
SMY 2
Eyepiece View
32x
Dawes: 1.9″
TFOV: 1.6°
Realistic = true angular size
Sep: 177.0″ · PA: 287° · N up, E left
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 3.1″
Size Comparison
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Stellar Lifecycle
Spectral Classification
Hertzsprung-Russell Diagram
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Blackbody Spectrum
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
Stellar Notes
Companion is A0V, optical, vsini =<54k/s.
Color excess E(B-V) = +0.02.
Probable member OB group near Omicron CMa; member Collinder 121 (#34).
Circumstellar shell.
Aludra.
Diam. = 0.00072 - 0.00075".
Survey Image
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