
science & techESA/Hubble
Hubble's last image from its WFPC2 camera shows a dying star wrapping its gas in glowing rings
This Hubble image shows Kohoutek 4-55, a planetary nebula about 4600 light-years away in the constellation Cygnus. Planetary nebulae form when a red giant star has used up its fuel and sheds its outer layers of gas. Its exposed core heats up and emits ultraviolet light that ionises the surrounding gas, making it glow, with nitrogen shown in red and orange, hydrogen in green and oxygen in blue. Kohoutek 4-55 has a multi-layered shape, with a bright inner ring, a fainter outer ring and a broad halo of nitrogen. The data were taken just ten days before the Wide Field and Planetary Camera 2 was removed from Hubble in 2009, after 16 years of service. The camera had been installed in 1993 and was replaced by Wide Field Camera 3, so this picture is its final send-off.
It shows how stars like the Sun end their lives, returning gas to space for future stars and planets. It also marks the retirement of an instrument behind many of Hubble's best-known images.
