This week’s image from the Hubble Space Telescope shows a dramatic spiral galaxy called NGC 5486, which is shot through with wisps of pink showing regions where new stars are being born.
Located 110 million light-years away in the famous constellation of Ursa Major, this galaxy is a type called an irregular spiral galaxy because its arms are wandering and indistinct. If you compare the image of this galaxy to one of a quintessential spiral galaxy like NGC 2336, you’ll see that a non-irregular spiral galaxy has clearly defined arms that reach out from its center and are symmetrical.
As Hubble scientists point out in their description of this irregular spiral galaxy, it also sits nearby to a very famous spiral galaxy called the Pinwheel Galaxy. The Pinwheel is a type called a grand design spiral galaxy because it is so neat and organized, with clear prominent arms and a very regular structure. The Pinwheel galaxy was observed by Hubble in 2006 when it was the largest and most detailed image of a spiral galaxy ever taken by Hubble, made by combining 51 individual Hubble images and adding some elements from ground-based telescopes as well.
The comparatively messy structure of galaxy NGC 5486 doesn’t mean it isn’t of scientific interest though. It was studied as part of a series of observations into supernovae, when a massive star runs out of fuel and collapses, giving off a huge burst of energy.
“This observation comes from a selection of Hubble images exploring debris left behind by Type II supernovae,” Hubble scientists write. “As massive stars reach the end of their lives, they cast off huge amounts of gas and dust before ending their lives in titanic supernova explosions. NGC 5486 hosted a supernova in 2004, and astronomers used the keen vision of Hubble’s Advanced Camera for Surveys to explore the aftermath in the hopes of learning more about these explosive events.”