Diphda is the orange giant that is usually the brightest star of Cetus, the sea monster, alone in an empty stretch of the autumn sky south of Pisces.
At a glance
| type | orange giant (class K) |
|---|---|
| distance from the Sun | 96.3 light-years (29.5 pc) |
| its light left it | 96.3 years ago |
| luminosity | 147 × the Sun |
| radius | 15.2 × the Sun |
| surface temperature | 5,150 K |
| constellation | Cetus (Sea Monster) |
Read off the piece’s own catalogue, the same values it draws with.
About Diphda
Diphda is a class K giant, a star that has finished burning hydrogen in its core and now burns helium there, a stage astronomers call the red clump. It is swollen to many times the Sun’s width and cooler at its surface. It also gives off X-rays, a sign of an active outer atmosphere.
The name comes from the Arabic for the second frog; the first frog is Fomalhaut, lower in the same part of the sky. Its other name, Deneb Kaitos, means the tail of the sea monster, and that is the part of Cetus it marks. Although Menkar carries the alpha label, Diphda normally outshines it. It is one of the stars listed for celestial navigation.
What you see in the piece
Diphda sits in a part of the sky with few bright stars, which is why it is easy to find from Earth. In the piece it is an orange point, its colour set by its cool surface.
Questions
What is the brightest star in Cetus?
Diphda, the tail of the sea monster, is normally the brightest, brighter than Menkar; Mira can briefly rival it at its peaks.
How far away is Diphda?
Diphda is 96.3 light-years (29.5 pc) from the Sun.