What kind of star is Kochab?
Kochab, catalogued as Beta Ursae Minoris (β UMi), appears in the official constellation Ursa Minor. Its apparent visual magnitude is about 2.07, while its estimated distance is about 131 light-years. Astronomers classify the object as K4 III orange giant. These labels describe temperature, luminosity class or system components; they should not be read as a claim that every naked-eye point is a single isolated star.
Kochab is a K-type giant that has left the main sequence after exhausting central hydrogen. Its expanded, cooler photosphere gives it a warm colour that contrasts with Polaris. Radial-velocity observations have produced claims of a planetary-mass companion, but the interpretation of long-period signals around evolved, active stars requires care; it is safer to distinguish a reported candidate from an uncontested visual fact. Kochab’s current distance from the celestial pole is much larger than Polaris’s. Its earlier usefulness arose from precession of Earth’s axis, not from motion of the star into a special physical location.
The coordinate pair RA 14h 50m 42.33s, Dec +74° 09′ 19.8″ fixes the object's direction on the celestial sphere for the J2000 reference epoch. Right ascension works like celestial longitude measured in hours, while declination works like latitude north or south of the celestial equator. Proper motion and improved measurements can refine catalogue positions, but these coordinates are sufficiently precise for a finder chart or planetarium search.
Kochab data at a glance
| Proper name | Kochab | Catalogue designation | Beta Ursae Minoris (β UMi) |
|---|---|---|---|
| Constellation | Ursa Minor | Apparent magnitude | about 2.07 |
| Spectral or system type | K4 III orange giant | Estimated distance | about 131 light-years |
| Right ascension (J2000) | 14h 50m 42.33s | Declination (J2000) | +74° 09′ 19.8″ |
Values are rounded for an observer-friendly overview. Consult the linked SIMBAD record for component-level identifiers, bibliography, measurement provenance and newer catalogue values.
The name Kochab
Kochab comes from Arabic al-kawkab, “the star,” shortened from a longer description identifying the northern star. The name reflects an earlier era when it was closer to the pole than Polaris was.
Around the time of the Middle Kingdom in Egypt, roughly four millennia ago, the north celestial pole lay between Kochab and nearby Pherkad. The pair therefore offered a practical northern reference even though neither sat exactly on the pole. Their later nickname, Guardians of the Pole, captures that geometry. The Arabic-derived proper name also preserves the star’s polar association; the IAU standardized Kochab for Beta Ursae Minoris in 2016.
Modern professional catalogues retain identifiers such as the Bayer designation alongside a proper name. The International Astronomical Union standardizes which name belongs to which component—an important distinction for systems whose combined light looks like one star from Earth.
How to find Kochab
Kochab and Pherkad form the outer edge of the Little Dipper’s bowl and are called the Guardians of the Pole. Locate Polaris, follow the faint handle toward the bowl, and look for the brighter orange member of the final pair. Binoculars help under urban skies.
Circumpolar from most northern temperate locations; below the horizon throughout the Southern Hemisphere. Visibility on a particular night still depends on latitude, season, time, horizon obstructions, weather and local light pollution. Use the interactive atlas below to check the surrounding field before observing.
Observation checklist
- Use Polaris to trace the Little Dipper’s faint handle toward its bowl.
- Kochab is the brighter and more orange of the bowl’s two outer stars.
- At high northern latitudes, watch Kochab circle the pole without setting.
- From a bright city, binoculars may show the Little Dipper bowl when the handle largely disappears.
Interesting facts about Kochab
- Kochab and Pherkad are traditionally called the Guardians of the Pole.
- Kochab is an evolved orange giant, not a Sun-like dwarf.
- Precession placed the ancient north celestial pole closer to Kochab’s side of Ursa Minor.
- It is the second-brightest star in Ursa Minor after Polaris.
- A proposed planet around Kochab should be described cautiously because giant-star velocity signals can be complex.
Continue from Kochab into the night sky
Use the Ursa Minor constellation guide to place this star within its larger pattern. When you are ready to observe, compare dark-sky places, find a nearby observatory, or follow our practical guide to finding a star in the night sky. Symbolically registered names are kept separately in the searchable Star-Register catalogue.
Sources and further reading
Measurements are rounded for readability. Multiple systems, variable stars and distant supergiants can have component-specific or model-dependent values. Survey panels show photographic sky fields, not the physical surface of the star.