Azernews.Az

By Alimat Aliyeva

NGC 7722 is located approximately 187 million light-years from Earth in the constellation Pegasus. Also known by its catalog names IRAS 23361+1540, LEDA 71993, and UGC 12718, this lenticular galaxy was first discovered by German astronomer Heinrich Louis d’Arrest on August 12, 1864, Azernews reports, citing foreign media.

“A lenticular (lens-shaped) galaxy is a type that occupies a middle ground between the more familiar spiral galaxies and elliptical galaxies,” astronomers from Hubble said in a statement.

“These galaxies are also less common than the other two types, in part because their appearance can be ambiguous, making it difficult to classify them definitively as either spiral, elliptical, or something in between.”

“Many lenticular galaxies exhibit features from both spiral and elliptical galaxies,” they explained. “In the case of NGC 7722, it lacks the well-defined arms characteristic of a spiral galaxy. However, it has an extended, glowing halo and a bright central bulge, similar to those found in elliptical galaxies.”

“Unlike elliptical galaxies, NGC 7722 retains a visible disk, with concentric rings swirling around its bright nucleus,” they added.

The galaxy’s most striking feature is the long, winding lanes of dark red dust that coil around its outer disk and halo.

The new image of NGC 7722, captured by Hubble’s Wide Field Camera 3 (WFC3), brings these stunning dust lanes into sharp focus, revealing the intricate structure of the galaxy in unprecedented detail.

“Dust bands like those seen in NGC 7722 are not uncommon in lenticular galaxies, and they stand out against the smooth, broad halo of light that typically surrounds these galaxies,” astronomers noted.

The unique dust lanes of NGC 7722 are believed to be the result of a past merger with another galaxy, a phenomenon often seen in lenticular galaxies.

“While the precise formation process of lenticular galaxies remains unclear, it’s widely accepted that mergers and other gravitational interactions play a crucial role in their evolution. These events can reshape galaxies, depleting their gas reserves while simultaneously bringing in new dust and material,” the astronomers explained.

Lenticular galaxies, like NGC 7722, are often considered to be “fossil galaxies,” as many of them appear to be in the later stages of their evolution. They typically lack the gas and dust needed to form new stars, making them less active than their spiral counterparts. However, the presence of these dark dust lanes suggests that some lenticular galaxies, such as NGC 7722, might still be undergoing subtle changes, hinting at their complex and dynamic histories.