Star Stars · In Centaurus
Toliman
Toliman, α² Centauri, is an orange main-sequence star in Centaurus: the 22nd brightest star in the night sky.
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- Constellation
- Centaurus
- Designation
- α² Centauri
- Apparent magnitude
- 1.35 · 22nd brightest star in the night sky
- Spectral class
- K1V
- Distance
- 4.3 light-years
- Highest at midnight
- late April
- Position (J2000)
- RA 14h 40m · Dec −60° 50′
An orange main-sequence star, around 5,100 K, like Arcturus and Aldebaran. About 110× brighter than the faintest star the eye can see. Gives off about 42% of the Sun's visible light. The light you are seeing left in 2022.
When to see it
On the night of Thu 29 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 | Never rises | ||
| Singapore GMT+8 | 19:27 | 01:16 · 28° | 07:06 |
| Sydney GMT+10 | Never sets | 00:07 · 63° | — |
Common questions
- Can I see it from 50° north?
- No. From there it never rises: you would have to travel south of 29° north before it cleared the horizon at all.
- Can I see it from 35° south?
- Yes, on any clear night of the year. From there it never sets: it is circumpolar, circling the pole and still 6° up at its lowest.
- When is the best time of year to see it?
- Around late April, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by late July 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 4.3 light-years away, and shines at magnitude 1.35 in our sky. From that far, the Sun would be a star of magnitude 0.4: one of the brightest in the night sky.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 1.35 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Rigil Kentaurus: Toliman is 19″ south-west of it, well under a Moon width.
Look for
From 50° north and 35° north it never rises; from the equator it climbs to 29°; from 35° south it is circumpolar and never sets.
Science
Toliman’s surface is about 5,100 K, some 700 K cooler than the Sun’s 5,772 K, so its light is strongest at about 570 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 5.7.
Did you know
Against Rigil Kentaurus, the brighter star the hop starts from: Rigil Kentaurus looks 4.4 times as bright as Toliman in our sky; Rigil Kentaurus is 4 light-years away and Toliman 4 light-years, so side by side Rigil Kentaurus would give off 4.4 times as much light as Toliman.
Science
Toliman is the nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Rigil Kentaurus, about 0.0004 light-years from it; on our sky the two are 19″ apart.
Look for
The Sun passes 43° north of Toliman around late October, when it is highest at noon, in daylight: the weeks either side are its worst time of year. It is 1° from the plane of the Milky Way, inside the band a dark sky shows.