Adhara is a blue-white giant in Canis Major and the brightest source of extreme ultraviolet light in our sky, its Arabic name meaning the maidens.
At a glance
| type | blue-white giant (class B) |
|---|---|
| distance from the Sun | 405 light-years (124 pc) |
| its light left it | 405 years ago |
| luminosity | 23,600 × the Sun |
| radius | 10.6 × the Sun |
| surface temperature | 22,000 K |
| constellation | Canis Major (Great Dog) |
Read off the piece’s own catalogue, the same values it draws with.
About Adhara
Adhara is a hot, massive blue-white star, larger than the Sun and enormously brighter, much of its light in the ultraviolet. Satellites that looked at the sky in extreme ultraviolet, light that is almost entirely absorbed by gas between the stars, found Adhara the brightest source of all, because the space between us and it happens to be unusually clear.
In the figure of the Great Dog it marks the hindquarters, part of a triangle with Wezen and Aludra. The name comes from Arabic for the maidens. It is one of the stars used for celestial navigation.
What you see in the piece
Adhara lies in a direction where the gas around the Sun is unusually thin, a gap leading out of the Local Bubble; turn on the Local Bubble to see the cavity its light crosses.
Questions
Why is Adhara bright in ultraviolet?
Adhara is a hot blue-white star at 22,000 K, and the gas between it and the Sun is unusually thin, so its extreme ultraviolet light is not absorbed on the way.