Star Stars · In Canis Major
Adhara
Adhara, ε Canis Majoris, is a blue-white bright giant in Canis Major: the 24th brightest star in the night sky.
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- Constellation
- Canis Major
- Designation
- ε Canis Majoris
- Apparent magnitude
- 1.50 · 24th brightest star in the night sky
- Spectral class
- B2II
- Distance
- 405 light-years
- Highest at midnight
- early January
- Position (J2000)
- RA 06h 59m · Dec −28° 58′
A blue-white bright giant, around 26,000 K, like Rigel and Spica. About 100× brighter than the faintest star the eye can see. Gives off about 3,300 times the Sun's visible light. The light you are seeing left around 1621.
When to see it
On the night of Sat 2 Jan 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 21:07 | 00:10 · 9° | 03:13 |
| New York EST | 19:59 | 00:05 · 20° | 04:10 |
| Singapore GMT+8 | 19:19 | 01:15 · 60° | 07:11 |
| Sydney GMT+11 | 17:40 | 01:06 · 85° | 08:33 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 11° up in the south.
- Can I see it from 35° south?
- Yes, and well placed: at its highest it passes almost overhead, 84° up, above most of the air’s haze.
- When is the best time of year to see it?
- Around early January, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early April it is highest in the early evening, and in early October not until the hours before dawn.
- How far away is it, and how bright?
- It is 405 light-years away, and shines at magnitude 1.50 in our sky. From that far, the Sun would be a star of magnitude 10.3: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 1.50 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Sirius: Adhara is 13° south of it, a fist and a half at arm’s length.
Look for
From 50° north it climbs to 11°; from 35° north it climbs to 26°; from the equator it climbs to 61°; from 35° south it climbs to 84°.
Science
Adhara’s surface is about 26,000 K, some 20,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 110 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 −4.0, brighter than Sirius, the brightest star in our sky.
Did you know
Against Sirius, the brighter star the hop starts from: Sirius looks 15 times as bright as Adhara in our sky, but Sirius is 9 light-years away and Adhara 405 light-years, so side by side Adhara would give off 150 times as much light as Sirius.
Science
Adhara is the 118th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Mirzam, about 140 light-years from it; on our sky the two are 14° apart.
Look for
The Sun passes 51° north of Adhara around early July, 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 6 hours a day, from 35° north about 9 and from 35° south about 15. It is 11° from the plane of the Milky Way.