Star Stars · In Carina
Miaplacidus
Miaplacidus, β Carinae, is a white subgiant in Carina: the 30th brightest star in the night sky.
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- Constellation
- Carina
- Designation
- β Carinae
- Apparent magnitude
- 1.67 · 30th brightest star in the night sky
- Spectral class
- A2IV
- Distance
- 113 light-years
- Highest at midnight
- early February
- Position (J2000)
- RA 09h 13m · Dec −69° 43′
A white subgiant, around 9,500 K, like Sirius and Vega. About 86× brighter than the faintest star the eye can see. Gives off about 220 times the Sun's visible light. The light you are seeing left around 1913.
When to see it
On the night of Fri 5 Feb 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | Never rises | ||
| New York EST | Never rises | ||
| Singapore GMT+8 | 19:31 | 01:15 · 19° | 07:00 |
| Sydney GMT+11 | Never sets | 01:06 · 54° | — |
Common questions
- Can I see it from 50° north?
- No. From there it never rises: you would have to travel south of 20° 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 15° up at its lowest.
- When is the best time of year to see it?
- Around early February, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early May it is highest in the early evening, and in early November not until the hours before dawn.
- How far away is it, and how bright?
- It is 113 light-years away, and shines at magnitude 1.67 in our sky. From that far, the Sun would be a star of magnitude 7.5: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 1.67 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Acrux: Miaplacidus is 20° south-west of it, a spread hand at arm’s length.
Look for
From 50° north and 35° north it never rises; from the equator it climbs to 20°; from 35° south it is circumpolar and never sets.
Science
Miaplacidus’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 −1.0.
Did you know
Against Acrux, the brighter star the hop starts from: Acrux looks 2.3 times as bright as Miaplacidus in our sky; Acrux is 322 light-years away and Miaplacidus 113 light-years, so side by side Acrux would give off 19 times as much light as Miaplacidus.
Science
Miaplacidus is the 59th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Alsephina, about 41 light-years from it; on our sky the two are 15° apart.
Look for
The Sun passes 72° north of Miaplacidus around early August, when it is highest at noon, in daylight: the weeks either side are its worst time of year. It is 14° from the plane of the Milky Way.