Polaris
HIP 11767; Alpha UMi; 1 UMi
HIP 11767; Alpha UMi; 1 UMi
DoubleStar
UMi
Visible
Level 3
Medium telescope (6-8") - Requires steady seeing
Physical Properties
Magnitude
2.02
Range
1.96 - 2.03
Period
4.0 days
Variable Type
Classical Cepheid (First Overtone)
Spectral Type
F8Ib
Star Color
Yellow
(B-V 0.60)
Temperature
6062 K
Radius
37.6 R☉
Distance
432 ly
Position & Identifiers
RA
02h 31m 48.7s
Dec
+89° 15' 51.0"
Constellation
UMi
HR
424
HIP
11767
Bayer
Alpha
Flamsteed
1 UMi
Variable ID
Alp UMi
Double Cat
1477
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Visibility
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Light Curve
Multiple Star System C,D: optical
Components
5
Component IDs
AB
Separation
18.4″
Companion Mag
9.1
Companion Sp
F3V
Position Angle
236°
Star Colors
A: Yellow
B: Yellow-white
Discoverer
STF 93
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
Sep: 18.4″ · PA: 236° · N up, E left
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 3.1″
Size Comparison
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 Fusion
Stellar Notes
CDelta 1.92 - 2.07V, 3.969778d. Period increases 53 sec./century. Probably unreddened.
A* 2.0 var. F8Ib, 30.46y, a = 0.038". AB physical; B, 8.20V, +0.49(B-V), +0.16(U-B), F3V, 0.0 color excess, | vsini =<60k/s; C, 13v at 43"; D, 14v at 83".
ADS 1477A, K 4.1k/s, V0 -16.4k/s, asini 482. Period 6-8y? Unresolved by speckle interferometry. RV varies in 2 | periods, 3.968d pulsation, 27.6y revolution of unseen blue companion.
Red star Pleiades group.
Also classified F7Ib-F8Ib.
0.006".
POLARIS; Alruccabah; Cynosura; Phoenice; Lodestar; Pole Star; Tramontana; Angel Stern; Navigatoria; Star of Arcady; | Yilduz; Mismar.
Survey Image
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