Astronomers using the NASA/ESA Hubble Space Telescope have captured a new photo of the lenticular galaxy NGC 7722.
This Hubble image shows NGC 7722, a lenticular galaxy some 187 million light-years away in the constellation of Pegasus. Image credit: NASA / ESA / Hubble / R.J. Foley, UC Santa Cruz / Dark Energy Survey / DOE / FNAL / DECam / CTIO / NOIRLab / NSF / AURA / Mehmet Yüksek.
NGC 7722 lies approximately 187 million light-years away from Earth in the constellation of Pegasus.
Also known as IRAS 23361+1540, LEDA 71993 and UGC 12718, this lenticular galaxy was first discovered by the German astronomer Heinrich Louis d’Arrest on August 12, 1864.
NGC 7722 is part of the NGC 7711 group, a gathering of seven large galaxies.
“A lenticular (lens-shaped) galaxy is a type that sits in between the more familiar spiral galaxies and elliptical galaxies,” the Hubble astronomers said in a statement.
“It is also less common than these — partly because when a galaxy has an ambiguous appearance, it can be hard to determine if it is actually a spiral, an elliptical galaxy, or something in between.”
“Many of the known lenticular galaxies sport features of both spiral and elliptical galaxies.”
“In this case, NGC 7722 lacks the defined arms of a spiral galaxy, while it has an extended, glowing halo and a bright bulge in the center similar to an elliptical galaxy,” they explained.
“Unlike elliptical galaxies, it has a visible disk — concentric rings swirl around its bright nucleus.”
“Its most prominent feature, however, is undoubtedly the long lanes of dark red dust coiling around the outer disk and halo.”
The new image of NGC 7722 from Hubble’s Wide Field Camera 3 (WFC3) instrument brings the galaxy’s impressive dust lanes into sharp focus.
“Bands of dust like this are not uncommon in lenticular galaxies, and they stand out against the broad, smooth halo of light that typically surrounds lenticular galaxies,” the astronomers said.
“The distinctive dust lanes of NGC 7722 are thought to result from a merger with another galaxy in the past, similar to other lenticular galaxies.”
“It is not yet fully understood how lenticular galaxies form, but mergers and other gravitational interactions are thought to play an important part, reshaping galaxies and exhausting their supplies of gas while bringing new dust.”