Achird
HIP 3821; Eta Cas; 24 Cas
Observable Double Star
Excellent (74/100)
Sep: 13.5", Companion: mag 7.4
HIP 3821; Eta Cas; 24 Cas
DoubleStar
Cas
Visible
Level 2
Small telescope (4") - Requires steady seeing
Physical Properties
Magnitude
3.44
Spectral Type
F9V
Star Color
Yellow
(B-V 0.57)
Distance
18.5 ly
Position & Identifiers
RA
00h 49m 06.0s
Dec
+57° 48' 57.0"
Constellation
Cas
HR
219
HIP
3821
Bayer
Eta
Flamsteed
24 Cas
Double Cat
671
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Visibility
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Multiple Star System
Components
8
Component IDs
AB
Separation
13.5″
Companion Mag
7.4
Companion Sp
M
Position Angle
328°
Star Colors
A: Yellow
B: Red
Discoverer
STF 60
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
Sep: 13.5″ · PA: 328° · 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
AB 3.45 G3V, 7.51 K4Ve, 480y, a = 11.994". Combined mag., colors. Component B, vsini =<25k/s. Companions C-H optical. | A possible invisible companion with period about 40y. Component B, 7.51V, +1.39(B-V), +1.03(U-B).
ADS 671A, 9.209d, K 2.2k/s, V0 +9.2k/s, asini 0.254. More recent observations by Morbey and Griffin (1987) and | by McMillan and Smith (1988) show constant velocity; thus, the SB nature of the system is questioned.
0.177".
Component B, +11k/s.
Achird, according to Becvar; Allen says "unnamed".
Survey Image
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