Alhena
HIP 31681; Gamma Gem; 24 Gem
HIP 31681; Gamma Gem; 24 Gem
DoubleStar
Gem
Visible
Level 3
Medium telescope (6-8") - Requires steady seeing
Physical Properties
Magnitude
1.93
Spectral Type
A1.5IV
Star Color
White
(B-V 0.00)
Distance
108.6 ly
Position & Identifiers
RA
06h 37m 42.7s
Dec
+16° 23' 57.0"
Constellation
Gem
HR
2421
HIP
31681
Bayer
Gamma
Flamsteed
24 Gem
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Visibility
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Multiple Star System
Components
3
Component IDs
AC
Separation
140.5″
Companion Mag
13.0
Position Angle
296°
Star Colors
A: White
Discoverer
BUP 90
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
Sep: 140.5″ · PA: 296° · 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
A* 1.93 A0IV, 12.9y, a = 0.038".
12.4y. Unresolved by speckle interferometry. RV also var. 0.13d.
Color excess E(B-V) = +0.03.
ALHENA.
Diam. = 0.00132 - 0.00139".
Survey Image
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