The Spiral Planetary Nebula

NGC 5189, nicknamed the Spiral Planetary Nebula, is a planetary nebula stretching across three light years in the southern constellation of Musca (The Fly). It was discovered by James Dunlop in 1 July 1826. For many years, it was thought to be a bright emission nebula, until 1967, when Karl Gordon Henize described NGC 5189 as a quasi-planetary based on its spectral emissions, having an S shape, reminiscent of a barred spiral galaxy. It is symmetrical and is estimated to be between 1,780 light years to 3,000 light years away from Earth.

The intricate structure of the stellar eruption, taken by the NASA/ESA Hubble Space Telescope, looks like a giant and brightly coloured ribbon in space, with most of it knotty and filamentary in its structure. Hubble’s image is the most detailed yet made of this object. As a result of the mass-loss process, the planetary nebula has been created with two nested structures, tilted with respect to each other, that expand away from the center in different directions. The bright golden ring that twists and tilts through the nebula is made up of a large collection of radial filaments and cometary knots. These are usually formed by the combined action of photo-ionizing radiation and stellar winds. Its double bipolar or quadrupolar structure could be explained by the presence of a second star orbiting the central star and influencing the pattern of mass ejection during its nebula-producing death throes. The remnant of the central star, having lost much of its mass, now lives its final days as a white dwarf.

Planetary nebulae represent a final brief stage in the life of a star like the Sun. While consuming the last of the fuel in its core, the star expels a large portion of its outer regions, which then heats up and glows brightly, showing intricate structures that scientists are still trying to fully understand. The gas and radiation flowing out from the dying star carves out shapes in the clouds, forming glowing bow-wave-like patterns towards the centre of the nebula. The knots in NGC 5189 are a reminder of just how vast the planetary nebula is. They might look like mere details in this image, but each and every one is a similar size to the entire Solar System. The star at the centre of the nebula, a dense white dwarf, is far too small to see as anything other than a point of light, even though it is roughly the size of the Earth.

Credits: Hubble, NASA, Wikipedia.