Free Astronomy Magazine November-December 2017

37 NOVEMBER-DECEMBER 2017 SPACE CHRONICLES seems that it is being de- stroyed. There are several potential mechanisms for this destruction. The inner shell is essentially an ex- panding shock wave, so it may be smashing into the dust grains and obliterating them, or producing an extra heating ef- fect that evaporates the dust. Mapping the gas and dust struc- tures within planetary nebulae will aid in understanding their role in the lives and deaths of low mass stars, and it will also help as- tronomers understand how plane- tary nebulae acquire their strange and complex shapes. But MUSE’s capabilities extend far beyond planetary nebulae. This sensitive instrument can also study the formation of stars and galaxies in the early Universe, as well as map the dark matter distri- bution in galaxy clusters in the nearby Universe. T his view shows how the MUSE instrument on ESO’s Very Large Telescope gives a three- dimensional depiction of the Saturn Nebula. For each part of this spectacular nebula, the light has been split up into its component colours — revealing in detail the chemical and physical properties of each pixel. During the subsequent analysis the astronomer can move through the data and study different views of the object at different wavelengths, just like tuning a television to different channels at different frequencies. [ESO/J. Walsh] star, visible in this image, which is in the process of becoming a white dwarf. In order to better understand how planetary nebulae are moulded into such odd shapes, an interna- tional team of astronomers led by Jeremy Walsh from ESO used the Multi Unit Spectroscopic Explorer (MUSE) to peer inside the dusty veils of the Saturn Nebula. MUSE is an instrument installed on one of the four Unit Telescopes of the Very Large Telescope at ESO’s Paranal Ob- servatory in Chile. It is so powerful because it doesn’t just create an image, but also gathers information about the spectrum — or range of colours — of the light from the ob- ject at each point in the image. The team used MUSE to produce the first detailed optical maps of the gas and dust distributed throughout a planetary nebula. The resulting image of the Saturn Nebula reveals many intricate struc- tures, including an elliptical inner shell, an outer shell, and a halo. It also shows two previously imaged streams extending from either end of the nebula’s long axis, ending in bright ansae (Latin for “handles”). Intriguingly, the team also found a wave-like feature in the dust, which is not yet fully understood. Dust is distributed throughout the nebula, but there is a significant drop in the amount of dust at the rim of the inner shell, where it !