Star Stars · In Vela
Alsephina
Alsephina, δ Velorum, is a white main-sequence star in Vela: the 46th brightest star in the night sky.
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- Constellation
- Vela
- Designation
- δ Velorum
- Apparent magnitude
- 1.93 · 46th brightest star in the night sky
- Spectral class
- A1V
- Distance
- 80.6 light-years
- Highest at midnight
- late January
- Position (J2000)
- RA 08h 45m · Dec −54° 43′
A white main-sequence star, around 9,800 K, like Sirius and Vega. About 67× brighter than the faintest star the eye can see. Gives off about 87 times the Sun's visible light. The light you are seeing left around 1945.
When to see it
On the night of Fri 29 Jan 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 | 19:23 | 01:15 · 34° | 07:06 |
| Sydney GMT+11 | 14:19 | 01:06 · 69° | 11:53 |
Common questions
- Can I see it from 50° north?
- No. From there it never rises: you would have to travel south of 35° 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 70° up in the south.
- When is the best time of year to see it?
- Around late January, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by late April it is highest in the early evening, and in late October not until the hours before dawn.
- How far away is it, and how bright?
- It is 80.6 light-years away, and shines at magnitude 1.93 in our sky. From that far, the Sun would be a star of magnitude 6.8: 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 1.93 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Avior: Alsephina is 5.7° north-east of it, three fingers at arm’s length.
Look for
From 50° north it never rises; from 35° north it barely clears the horizon, at 0°; from the equator it climbs to 35°; from 35° south it climbs to 70°.
Science
Alsephina’s surface is about 9,800 K, some 4,000 K hotter than the Sun’s 5,772 K, so its light is strongest at about 300 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 0.0, about as bright as Arcturus looks to us.
Did you know
Against Avior, the brighter star the hop starts from: the two look about as bright as each other in our sky; Avior is 605 light-years away and Alsephina 81 light-years, so side by side Avior would give off 60 times as much light as Alsephina.
Science
Alsephina is the 35th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Miaplacidus, about 41 light-years from it; on our sky the two are 15° apart.
Look for
The Sun passes 67° north of Alsephina around late July, 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 1 hours a day and from 35° south about 23. It is 7° from the plane of the Milky Way, inside the band a dark sky shows.