Pleione is the mother star of the Pleiades, a fast-spinning blue-white star that throws off shells of gas and slowly changes its brightness and spectrum.
At a glance
| type | blue-white star (class B) |
|---|---|
| distance from the Sun | 444 light-years (136 pc) |
| its light left it | 444 years ago |
| luminosity | 190 × the Sun |
| radius | 3.2 × the Sun |
| surface temperature | 12,000 K |
Read off the piece’s own catalogue, the same values it draws with.
About Pleione
Pleione sits beside Atlas at the edge of the cluster. It is a Be star: it spins so fast that gas flows off its equator into a disc around it. Over years that disc builds up and disperses again, changing the star’s brightness and adding or removing emission lines in its spectrum.
These shell episodes make Pleione one of the best-studied stars of its kind. It also has a close companion, which may help shape the disc.
In myth Pleione was an Oceanid, a sea nymph, wife of Atlas and mother of the seven sisters. She is often lost in the glare of Atlas beside her.
What you see in the piece
In the Pleiades Pleione is a fainter blue-white star right next to Atlas, easily missed beside it.
Measured or modelled
The size of Pleione depends on how it is measured, because a star spinning this fast is flattened, wider at the equator than at the poles; the card gives a single value.
Questions
Why does Pleione change in brightness?
Pleione spins so fast that it throws gas into a disc around its equator; as the disc forms and disperses, the star brightens, dims and changes its spectrum.
Who was Pleione?
In Greek myth Pleione was a sea nymph, the wife of Atlas and the mother of the Pleiades.