Star Stars · In Ursa Minor
Kochab
Kochab, β Ursae Minoris, is an orange giant in Ursa Minor: the 59th brightest star in the night sky.
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- Constellation
- Ursa Minor
- Designation
- β Ursae Minoris
- Apparent magnitude
- 2.07 · 59th brightest star in the night sky
- Spectral class
- K4IIIvar
- Distance
- 131 light-years
- Highest at midnight
- early May
- Position (J2000)
- RA 14h 51m · Dec +74° 09′
An orange giant, around 4,600 K, like Arcturus and Aldebaran. About 59× brighter than the faintest star the eye can see. Gives off about 200 times the Sun's visible light. The light you are seeing left around 1895.
When to see it
On the night of Sun 2 May 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | Never sets | 01:08 · 67° | — |
| New York EDT | Never sets | 01:03 · 57° | — |
| Singapore GMT+8 | 18:55 | 01:13 · 17° | 07:31 |
| Sydney GMT+10 | Never rises | ||
Common questions
- Can I see it from 50° north?
- Yes, on any clear night of the year. From there it never sets: it is circumpolar, circling the pole and still 34° up at its lowest.
- Can I see it from 35° south?
- No. From there it never rises: you would have to travel north of 15° south before it cleared the horizon at all.
- When is the best time of year to see it?
- Around early May, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early August it is highest in the early evening, and in late January not until the hours before dawn.
- How far away is it, and how bright?
- It is 131 light-years away, and shines at magnitude 2.07 in our sky. From that far, the Sun would be a star of magnitude 7.8: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.07 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Polaris: Kochab is 17° north of it, a fist and a half at arm’s length.
Look for
From 50° north and 35° north it is circumpolar and never sets; from the equator it climbs to 16°; from 35° south it never rises.
Science
Kochab’s surface is about 4,600 K, some 1,200 K cooler than the Sun’s 5,772 K, so its light is strongest at about 630 nm, where the Sun’s is strongest at 500 nm. Moved to 33 light-years, the distance astronomers compare stars at, it would shine at magnitude −0.9.
Did you know
Against Polaris, the brighter star the hop starts from: the two look about as bright as each other in our sky; Polaris is 433 light-years away and Kochab 131 light-years, so side by side Polaris would give off 12 times as much light as Kochab.
Science
Kochab is the 64th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Athebyne, about 48 light-years from it; on our sky the two are 15° apart.
Look for
The Sun passes 73° south of Kochab around late October, when it is highest at noon, in daylight: the weeks either side are its worst time of year. It is 41° from the plane of the Milky Way.