IT may look like a supernatural apparition, but this mysterious blue bubble is actually the “ghost” of a star.
The shimmering orb, a shell of gas ejected by a dying star, is known as the Southern Owl Nebula, or ESO 378-1.
Astronomers obtained the striking image using the European Southern Observatory’s Very Large Telescope in northern Chile.
The Southern Owl is located in the constellation of Hydra and 4,300 light years from Earth.
It is a “planetary nebula” created by an ageing star with a mass less than around eight times that of the sun shedding its outer layers.
Ultraviolet radiation from the star’s core causes the gas “shell” to glow as it expands outwards.
After the nebula has faded, the leftover remnant at its centre will become a tiny, hot and very dense “white dwarf” that will slowly cool over millions of years.
The same fate awaits the sun, which will generate a planetary nebula several billion years in the future.
Stars with a mass greater than eight times the sun’s end their lives in more spectacular fashion with a supernova explosion.
Planetary nebulae play a crucial role in the evolution of the universe by scattering the elemental building blocks of other stars, planets, and possibly even life.