Hubble Unveils Lenticular Galaxy NGC 7722
The NASA/ESA Hubble Space Telescope has captured an image of NGC 7722, a lenticular galaxy located approximately 187 million light-years away in the constellation Pegasus. Lenticular galaxies are an uncommon type, positioned between spiral and elliptical galaxies in classification, often exhibiting characteristics of both.
Lenticular galaxies are an uncommon type, positioned between spiral and elliptical galaxies in classification, often exhibiting characteristics of both.
Distinctive Features of NGC 7722
NGC 7722 lacks the distinct arms of a spiral galaxy but possesses an extended, glowing halo and a bright central bulge, similar to an elliptical galaxy. It also features a visible disk with concentric rings around its nucleus.
A prominent characteristic of NGC 7722 is its long, dark red dust lanes that coil around the outer disk and halo. These dust lanes are thought to be the result of a past merger with another galaxy, a process believed to play a role in the formation of lenticular galaxies by reshaping them and exchanging gas and dust.
These dust lanes are thought to be the result of a past merger with another galaxy, a process believed to play a role in the formation of lenticular galaxies.
The Supernova SN 2020SSF
Despite having fewer new, young stars compared to spiral galaxies, NGC 7722 was the site of a Type Ia supernova, SN 2020SSF, detected in 2020. Type Ia supernovae occur when a white dwarf star in a binary system accumulates sufficient mass from a companion star to become unstable and explode.
These events produce a consistent level of light, making them valuable tools for astronomers to measure cosmic distances to galaxies by comparing their apparent brightness from Earth to their intrinsic luminosity.
Type Ia supernovae produce a consistent level of light, making them valuable tools for astronomers to measure cosmic distances.
Hubble's Aftermath Study
This specific Hubble image was taken as part of an observing program designed to study the aftermath of supernovae. Researchers observed NGC 7722 two years after SN 2020SSF faded.
This observation enabled them to search for radioactive material from the supernova, catalog neighboring stars to determine the original star's age, and identify the remnant companion star.