"As are you, O star of my skies," he called back, politely if untruthfully.

The structure of a subdwarf O star is believed to be a carbon and oxygen core surrounded by a helium burning shell.

During its main sequence, it would have been an O star with a mass of 15 to 35 M.

But that is you, O beautiful star!

O great star disappear'd - O the black murk that hides the star!

O windy star blown sideways up the sky!

They are O stars with strong magnetic fields.

O stars of heaven, that shone on me of old, as if to light me onward and upward!

It runs from the hottest blue O stars to the coolest red M stars.

O brilliant star that lights up the dawn!