Star Stars · In Centaurus
Kulou
Kulou, ι Centauri, is a white main-sequence star in Centaurus: the 125th brightest star in the night sky.
Save the chart (SVG) Tactile chart (A4 SVG)
- Constellation
- Centaurus
- Designation
- ι Centauri
- Apparent magnitude
- 2.75 · 125th brightest star in the night sky
- Spectral class
- A2V
- Distance
- 58.8 light-years
- Highest at midnight
- early April
- Position (J2000)
- RA 13h 21m · Dec −36° 43′
A white main-sequence star, around 9,500 K, like Sirius and Vega. About 32× brighter than the faintest star the eye can see. Gives off about 22 times the Sun's visible light. The light you are seeing left in 1967.
When to see it
On the night of Fri 9 Apr 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | 23:52 | 01:10 · 2° | 02:28 |
| New York EDT | 21:46 | 01:05 · 12° | 04:24 |
| Singapore GMT+8 | 19:20 | 01:15 · 52° | 07:10 |
| Sydney GMT+10 | 16:07 | 00:06 · 87° | 08:06 |
Common questions
- Can I see it from 50° north?
- Only just. At its highest it is 3° above the southern horizon, so it needs a clear, flat view that way and clean air.
- Can I see it from 35° south?
- Yes, and well placed: at its highest it passes almost overhead, 88° up, above most of the air’s haze.
- When is the best time of year to see it?
- Around early April, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early July it is highest in the early evening, and in early January not until the hours before dawn.
- How far away is it, and how bright?
- It is 58.8 light-years away, and shines at magnitude 2.75 in our sky. From that far, the Sun would be a star of magnitude 6.1: one you would need a dark country sky to see at all.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.75 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Menkent: Kulou is 9.3° west of it, a fist at arm’s length.
Look for
From 50° north it barely clears the horizon, at 3°; from 35° north it climbs to 18°; from the equator it climbs to 53°; from 35° south it climbs to 88°.
Science
Kulou’s surface is about 9,500 K, some 3,700 K hotter than the Sun’s 5,772 K, so its light is strongest at about 310 nm, in the ultraviolet, past the violet end of what the eye can see, 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 1.5, about as bright as Adhara looks to us.
Did you know
Against Menkent, the brighter star the hop starts from: Menkent looks 1.9 times as bright as Kulou in our sky; Menkent is 59 light-years away and Kulou 59 light-years, so side by side Menkent would give off 1.9 times as much light as Kulou.
Science
Kulou is the 22nd nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Menkent, about 9 light-years from it; on our sky the two are 9.3° apart.
Look for
The Sun passes 26° north of Kulou around early October, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 50° north it is above the horizon for about 4 hours a day, from 35° north about 8 and from 35° south about 16. It is 26° from the plane of the Milky Way.