Hubble Space Telescope image of the stunning silvery-blue spiral arms of the galaxy NGC 4848. Credit: ESA/Hubble & NASA, M. Gregg
A notable feature of most spiral galaxies is the multitude of arching spiral arms that seemingly spin out from the galaxy’s center. In this image, taken with the NASA/ESA Hubble Space Telescope, the stunning silvery-blue spiral arms of the galaxy NGC 4848 are observed in immense detail. Not only do we see the inner section of the spiral arms containing hundreds of thousands of young, bright, blue stars, but Hubble has also captured the extremely faint wispy tails of the outer spiral arms.
This wispy barred spiral galaxy was first discovered in 1865 by the German astronomer Heinrich Louis d’Arrest. In his career, Heinrich also notably discovered the asteroid 76 Freia and many other galaxies and he also contributed to the discovery of Neptune.
If you are situated in the Northern Hemisphere with a large telescope, you might just be able to observe the ghost-like appearance of this faint galaxy within faint constellation of Coma Berenices (Berenice’s Hair).
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters.
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about half of all spiral galaxies. Bars generally affect both the motions of stars and interstellar gas within spiral galaxies and can affect spiral arms as well. The Milky Way Galaxy, where our own Solar System is located, is classified as a barred spiral galaxy.
Heinrich Louis d’Arrest (August 13, 1822 – June 14, 1875; German pronunciation: [daˈʁɛ] ) was a German astronomer, born in Berlin. His name is sometimes given as Heinrich Ludwig d’Arrest.