Jupiter's Ghost: ESA astronomers capture image of dying star's planetary nebula

European Space Agency astronomers have captured the spectacular remnants of a dying star located 3,000 light years away, which offers a glimpse into how our sun would look eight billion years from now.

The image of Jupiter's Ghost, composed by several different images layered up that were snapped by the XMM-Newton telescope and the Hubble Telescope, shows what happens when small and medium stars die.

Rather than going out in a huge explosion (a supernova) like the big stars, smaller stars that are roughly the same size as our sun become planetary nebulas.

They shed their outer layers by "puffing up", i.e. the inside of the star gradually expands, and like a dying gasp, a shell of ionised gas is blown outwards by stellar winds as the star collapses.

When the layers of gas are expelled at the speed of 2,400km per second, the core of the dying star, a dense hot ball of carbon and oxygen known as a "White Dwarf" is exposed. It shines so brightly in the ultraviolet that it causes the shell of ionised gas around it to glow.

Jupiter's Ghost aka NGC 3242

Jupiter's Ghost is a nickname that was coined by astronomer William Herschel when he discovered planetary nebulas back in 1785.

Herschel thought that the planetary nebulas looked like the shapes of planets, even though really, they have nothing to do with planets at all.

They also aren't nebulas, which are interstellar clouds of gas and dust that fly around in space, and primarily are considered to be the places where stars were born.

The planetary nebula Herschel saw was NGC 3242, located in the constellation of Hydra, the water snake.

NGC 3242 is located about 2,000 light-years from Earth, and as it seemed to occupy the same amount of area in the sky as the planet Jupiter, he named it Jupiter's Ghost.

Ionised gases two light-years in length

In reality, Jupiter's Ghost is much larger than the planet Jupiter. Where Jupiter has a radius of 69,911km, the shell of ionised gas measures about two light-years from end to end.

ESA's XMM-Newton telescope collected X-ray data of NGC 3242, which represents the blue part of the image. The blue glow represents the inner shell of the planetary nebula, where gas heats to over two million degrees Celsius by shocks caused by the stellar wind.

The rest of the image, comprising of the green and red glows, come from the Hubble Space Telescope.

The green glow, on the other hand, shows the outer shell of cooler concentrations of gas as seen in optical light, while the red flame-shaped features are even cooler, low-ionisation pockets of gas moving at even faster speeds than the rest of the gases.