Star Stars · In Libra
Zubeneschamali
Zubeneschamali, β Librae, is a blue-white main-sequence star in Libra: the 104th brightest star in the night sky.
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- Constellation
- Libra
- Designation
- β Librae
- Apparent magnitude
- 2.61 · 104th brightest star in the night sky
- Spectral class
- B8V
- Distance
- 185 light-years
- Highest at midnight
- early May
- Position (J2000)
- RA 15h 17m · Dec −09° 23′
A blue-white main-sequence star, around 14,000 K, like Rigel and Spica. About 36× brighter than the faintest star the eye can see. Gives off about 240 times the Sun's visible light. The light you are seeing left around 1841.
When to see it
On the night of Sat 8 May 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | 20:01 | 01:12 · 29° | 06:23 |
| New York EDT | 19:41 | 01:07 · 40° | 06:33 |
| Singapore GMT+8 | 19:19 | 01:17 · 79° | 07:16 |
| Sydney GMT+10 | 17:44 | 00:08 · 66° | 06:33 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 31° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 64° up in the north.
- 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 early February not until the hours before dawn.
- How far away is it, and how bright?
- It is 185 light-years away, and shines at magnitude 2.61 in our sky. From that far, the Sun would be a star of magnitude 8.6: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.61 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Acrab: Zubeneschamali is 16° north-west of it, a fist and a half at arm’s length.
Look for
From 50° north it climbs to 31°; from 35° north it climbs to 46°; from the equator it climbs to 81°; from 35° south it climbs to 64°.
Science
Zubeneschamali’s surface is about 14,000 K, some 8,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 210 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 −1.2.
Did you know
Against Acrab, the brighter star the hop starts from: the two look about as bright as each other in our sky; Acrab is 404 light-years away and Zubeneschamali 185 light-years, so side by side Acrab would give off 5.3 times as much light as Zubeneschamali.
Science
Zubeneschamali is the 82nd nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Yed Prior, about 49 light-years from it; on our sky the two are 15° apart.
Look for
The Sun passes 8.5° south of Zubeneschamali around early November, 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 10 hours a day, from 35° north about 11 and from 35° south about 13. It is 39° from the plane of the Milky Way.