NGC 4689

A jewel in the queen’s hair (potw2421a).jpg
(c) ESA/Hubble, CC BY 4.0
This Picture of the Week shows the jewel-bright spiral galaxy NGC 4689, which lies 54 million light-years from Earth in the constellation Coma Berenices. This constellation has the distinction of being the only one of the 88 constellations officially recognised by the International Astronomical Union (IAU) to be named after an historical figure, Queen Berenice II of Egypt. The latin word ‘coma’ references her hair, meaning that NGC 4689 can be said to be found in the hair of a queen. Some people of Berenice’s time would have meant this quite literally, as the story goes that her court astronomer thought that a missing lock of Berenice’s hair had been catasterised (a word meaning ‘placed amongst the stars’) by the gods: hence the name of the constellation, Coma Berenices.NGC 4689 holds an interesting — albeit less royal — place in modern astronomy too. The Universe is so incredibly vast that at a distance of a mere 54 million light-years NGC 4689 is relatively nearby for a galaxy. This image has been made using data from two sets of observations, one made in 2019 and 2024, both of which were made as a part of programmes that observed multiple ‘nearby’ galaxies. The 2024 observing programme is an interesting example of how Hubble — a relatively old but extraordinarily productive telescope — can support the work of the technologically cutting-edge Webb telescope. Observations collected by Webb stand to transform our understanding of how galaxies transform and evolve over time, by providing data of an unprecedented level of detail and clarity. However, thanks to their complementary capabilities, new observations from Hubble — such as those used to create this image — can assist the work done using Webb. In this case, the Hubble data were collected in order to get a more accurate grasp of the stellar populations of nearby galaxies, which is crucial to understanding the evolution of galaxies. Thus, NGC 4689 is playing an important role in developing our understanding of how all galaxies evolve. In fact, it is observed enough that it has been the subject of a Hubble Picture of the Week before, in 2020. [Image Description: A spiral galaxy is viewed close up and fills most of the scene. It has a bright, glowing spot at the core, broad spiral arms that are covered by many dark threads of dust, and pink glowing spots across the disc that mark areas of star formation. The disc of the galaxy is surrounded by a faint halo that bleeds into the dark background.]