An Uneven Spiral in Vela
NGC 3318 is a barred spiral galaxy classified as SAB(rs)b located in the constellation Vela. The galaxy lies about 122 million light-years from Earth and appears with an angular size of 2.3 × 1.2 arcminutes, corresponding to a physical diameter of roughly 115,000 light-years.
At its center sits a luminous bulge embedded within a weak bar structure. From this region two spiral arms emerge and sweep outward across the disk. Dark dust lanes thread through the inner spiral pattern while scattered blue star-forming regions mark sites where young stellar clusters are forming. The arms are noticeably asymmetric, with one arm extending farther and appearing more fragmented than the other, giving the galaxy a disturbed appearance.
Just to the east of the main disk lies the faint companion PGC 573828, visible as a small bluish galaxy. Its proximity suggests it likely shares the same galactic environment as NGC 3318. Even modest companions can subtly reshape spiral galaxies over time, and the uneven spiral structure seen here may be the result of long-term gravitational interaction.
The wider field reveals a remarkable depth of the universe. Numerous faint background galaxies are scattered throughout the image, and near the upper portion of the frame a more distant spiral galaxy appears with its own distorted structure. These background systems emphasize that a single deep exposure captures galaxies spanning vast distances across the cosmos.
NGC 3318 illustrates how spiral galaxies are rarely perfectly symmetric systems. Interactions with neighboring galaxies, combined with the internal dynamics of bars and spiral density waves, continually reshape their disks, leaving visible signatures in warped arms, irregular star-forming regions, and disturbed spiral patterns
Imaged in LRGB on the ASA Astrosysteme AZ 1500 at Observatorio El Sauce, Chile.
Image Acquisition and Processing: Mike Selby