Polaris — Double Star in Ursa Minor
HIP 11767; Alpha Ursae Minoris; 1 Ursae Minoris
About Polaris
Description
Polaris (the North Star) is a yellow supergiant of spectral type F7Ib-II at magnitude 2.02 in Ursa Minor. Located about 431 light-years from Earth, it has a luminosity of roughly 1,260 times solar. Polaris is a Cepheid variable star, pulsating with a period of about 3.97 days. It is a triple star system — the faint companion Polaris B is visible in a small telescope.
Observing Tips
Polaris sits within 1 degree of the north celestial pole, making it the current pole star. Use the Big Dipper's Pointer Stars (Merak and Dubhe) to find it. Despite its fame, Polaris is only the 48th brightest star — it is important for its position, not its brilliance. Polaris B (magnitude 8.7) is a rewarding telescopic companion at 18 arcseconds separation. Visible year-round from the northern hemisphere.
History
Polaris has not always been the pole star — precession slowly shifts the celestial pole. It became useful as a pole indicator around 500 AD and will be closest to the pole around AD 2100. The name comes from Latin 'stella polaris.' Vikings, medieval navigators, and explorers have relied on it for over a millennium.
Fun Facts
Polaris is the nearest and brightest Cepheid variable to Earth, making it crucial for calibrating the Cepheid period-luminosity relation used to measure cosmic distances. Surprisingly, its pulsation amplitude has been decreasing over the past century and nearly stopped in the 1990s before increasing again — a mystery.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Hard+ | Hard+ | Hard+ |
| 150 mm Newton 150mm Newt. | Medium+ | Medium+ | Medium+ |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Light Curve
6Multiple Star System Quintuple C,D: optical
Separation over time
Slow change over generations — observable in lifetime comparisons.
Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.
Eyepiece View
A: 2.0 · B: 9.1 · Sep: 18.4″ · PA: 236° · N up, E right
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
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Size Comparison
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Compare Stars
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Spectral Classification
11
Hertzsprung-Russell Diagram
12
Stellar Lifecycle
13
Blackbody Spectrum
14
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
15
Stellar Fusion
Discover
16Stellar Notes
17
Light Travel Time Machine
18
Relativistic Travel
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.
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