Kocab — Star in Ursa Minor
HIP 72607; Beta Ursae Minoris; 7 Ursae Minoris
About Kocab
Description
Kocab is an orange giant of spectral type K4III at magnitude 2.08, the second brightest star in Ursa Minor. Located about 131 light-years from Earth, it has a luminosity of roughly 540 times solar. Kocab hosts a confirmed exoplanet discovered in 2014, with at least 6.1 Jupiter masses. Together with Pherkad, it forms the 'Guards of the Pole.'
Observing Tips
Kocab and Pherkad form the outer edge of the Little Dipper's bowl, appearing to circle protectively around Polaris at the handle's end. Kocab is the brighter of the two Guards. Its warm orange color contrasts with the whiter Polaris. Circumpolar from mid-northern latitudes and visible year-round.
History
The name Kocab derives from the Arabic 'al-kawkab,' meaning simply 'the star.' Around 1500-500 BC, Kocab was much closer to the north celestial pole than Polaris and served as a rough pole star for ancient civilizations including the Phoenicians and early Greeks.
Fun Facts
Kocab's exoplanet, discovered in 2014, is one of the few planets found orbiting a star that once served as a pole star. The planet has at least 6 Jupiter masses and orbits in about 522 days.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Easy |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
15
Exoplanets
1 known planet
View in 3D
| Planet | Radius | Mass | Period | Distance |
|---|---|---|---|---|
| bet UMi b | 12.70R⊕ | 6.10M♃ | 1.4yr | 126ly |
Habitable Zone
Size & Mass Comparison
About exoplanets — how we find them and which host stars you can observe
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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