An image from the Hubble space telescope released by the European Space Agency shows a dying star, roughly the same mass as the Sun, giving scientists a clue as to how the world as we know it could end.
The image of intricate swirls of gas offer a glimpse of the Sun’s distant future. In 5 billion years’ time, it will be dying and is expected to behave in the same way as in the main image shown, shedding its outer layers to reveal the burning core, which then becomes a slowly cooling ember known as a white dwarf.
As a star ages, the nuclear reactions that keep it shining begin to falter. This uncertain energy generation causes the stars to pulsate in an irregular way, casting off its outer layers into space. As the star sheds these outer gases, the super-hot core is revealed. It gives off huge quantities of ultraviolet light, and this radiation causes the gas shells to glow, creating the fragile beauty of the nebula.
The main image shows the planetary nebula Kohoutek 4-55, which is named after its discoverer, the Czech astronomer Luboš Kohoutec, and located 4600 light years from Earth, in the direction of the constellation Cygnus. A planetary nebula is formed from material in the outer layers of a red giant star that were expelled into interstellar space when the star was in the late stages of its life. Ultraviolet radiation emitted from the remaining hot core of the star ionises the ejected gas shells, causing them to glow.
This image was the final ‘pretty picture’ taken by the Hubble Space Telescope’s Wide Field Planetary Camera 2 (WFPC2). The camera was installed in 1993 and worked until 2009, offering a 16-year stretch of unparalleled observations.
WFPC2 took many of Hubble’s iconic images. They helped to make the space telescope a household name across the world.
This particular shot is a composite of three images, each taken at a specific wavelength to isolate the light coming from particular atoms of gas. The different wavelengths have been color-coded to aid recognition. Red signifies nitrogen gas, green shows hydrogen and blue represents oxygen.