Star Stars · In Centaurus
Leepwal
Leepwal, ζ Centauri, is a blue-white subgiant in Centaurus: the 98th brightest star in the night sky.
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- Constellation
- Centaurus
- Designation
- ζ Centauri
- Apparent magnitude
- 2.55 · 98th brightest star in the night sky
- Spectral class
- B2.5IV
- Distance
- 382 light-years
- Highest at midnight
- mid April
- Position (J2000)
- RA 13h 56m · Dec −47° 17′
A blue-white subgiant, around 25,000 K, like Rigel and Spica. About 38× brighter than the faintest star the eye can see. Gives off about 1,100 times the Sun's visible light. The light you are seeing left around 1644.
When to see it
On the night of Sun 18 Apr 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | Never rises | ||
| New York EDT | 23:43 | 01:04 · 2° | 02:26 |
| Singapore GMT+8 | 19:22 | 01:15 · 41° | 07:08 |
| Sydney GMT+10 | 15:00 | 00:06 · 76° | 09:12 |
Common questions
- Can I see it from 50° north?
- No. From there it never rises: you would have to travel south of 42° north before it cleared the horizon at all.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 78° up in the south.
- When is the best time of year to see it?
- Around mid April, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid July it is highest in the early evening, and in mid January not until the hours before dawn.
- How far away is it, and how bright?
- It is 382 light-years away, and shines at magnitude 2.55 in our sky. From that far, the Sun would be a star of magnitude 10.2: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.55 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Uridim: Leepwal is 7.9° west of it, a fist at arm’s length.
Look for
From 50° north it never rises; from 35° north it barely clears the horizon, at 8°; from the equator it climbs to 43°; from 35° south it climbs to 78°.
Science
Leepwal’s surface is about 25,000 K, some 19,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 120 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 −2.8, brighter than Sirius, the brightest star in our sky.
Did you know
Against Uridim, the brighter star the hop starts from: Uridim looks 1.3 times as bright as Leepwal in our sky; Uridim is 465 light-years away and Leepwal 382 light-years, so side by side Uridim would give off 1.9 times as much light as Leepwal.
Science
Leepwal is the 109th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is KeKouan, about 79 light-years from it; on our sky the two are 12° apart.
Look for
The Sun passes 33° north of Leepwal around mid October, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 35° north it is above the horizon for about 5 hours a day and from 35° south about 19. It is 14° from the plane of the Milky Way.