ETA CARINAE

Composite picture of Eta Carinae, showing the fine structure of the gas and dust clouds thrown off also called Keyhole Nebula, peculiar red star and nebula (catalog number NGC 3372) in the southern constellation Carina. The English astronomer Sir Edmond Halley noted it in 1677 as a star of about fourth magnitude. In 1838 Sir John Herschel observed it as a first-magnitude star. By 1843 it had reached its greatest recorded brightness, approximately -1 magnitude, or as bright as the brightest stars. Unlike the common types of exploding stars called novae and supernovae, it remained bright for several years. From about 1857 it faded steadily, disappearing to the unaided eye only about 1870. Since then it has varied irregularly about the seventh magnitude. The nebula around the star is an expanding shell of gas and dust, shaped like an hourglass with a disk at its centre. It is thought that the star's consumption of its nuclear fuel may be accelerating and that Eta Carinae may be a supernova at some future time.