Alphard is the brightest star of Hydra, an orange giant whose Arabic name means the solitary one, for it shines alone in an empty stretch of sky.
At a glance
| type | orange giant (class K) |
|---|---|
| distance from the Sun | 180 light-years (55.3 pc) |
| its light left it | 180 years ago |
| luminosity | 674 × the Sun |
| radius | 40.9 × the Sun |
| surface temperature | 4,600 K |
| constellation | Hydra (Female Water Snake) |
Read off the piece’s own catalogue, the same values it draws with.
About Alphard
The card describes a giant star: far wider than the Sun, much more luminous, and cooler at the surface, which gives its orange tint. It has exhausted the hydrogen at its core and expanded, as the Sun will one day.
The name comes from the Arabic al-fard, the solitary one. Hydra is vast but faint, and around Alphard there are no other bright stars, so it stands out alone. It has also been called Cor Hydrae, the heart of the snake, which is where it sits in the figure.
To find it, northern observers can follow a line from the Sickle of Leo south-west, or look south-east of the Beehive; it is the only conspicuous star in that part of the sky.
What you see in the piece
In the piece Alphard keeps its true brightness and orange colour. From the Earth it is the heart of the snake; from space the snake’s long chain of stars scatters through depth.
Questions
Why is Alphard called the solitary one?
Al-fard means the solitary one in Arabic: Alphard is the only bright star in a large, otherwise faint region of sky.
How far away is Alphard?
Alphard is 180 light-years (55.3 pc) from the Sun; its light left it 180 years ago.