While the James Webb Space Telescope has been getting a lot of press lately, its predecessor, the Hubble Space Telescope continues to impress; this time from the galaxy NGC 6956, a near-perfect example of a barred galaxy located about 214 million light-years from Earth.
Barred galaxies, which get their name from the very prominent “bar” of Oldest that cut through the galactic core are among the most common types of galaxies in the known universe They make up an estimated 70% of all galaxies (opens in new tab). Rod structures are also far more common in galaxies with active galactic cores, as gas and other matter is injected along these rods towards the galactic core.
This process helps to eventually destabilize the bar (opens in new tab)However, as more mass is directed to the galactic core, the bar becomes more unstable, eventually softening the bar into the more traditional spiral formation – like that of NGC 2985 (opens in new tab) – which most people think of when they think of a spiral galaxy.
Related: The best Hubble Space Telescope images ever!
according to a Image description from NASA (opens in new tab)was this latest photo of NGC 6956 to look at Cepheids variable stars, these are stars whose luminosity alternates between bright and dark at regular intervals. These periods of brightening and dimming are directly related to a star’s actual brightness. We are able to calculate these variations in apparent brightness with the star’s actual brightness, which allows us to determine its distance from us.
This is a crucial way for astronomers to determine the distance of extragalactic objects like NGC 6956, as there are currently few other ways to do it. There are other interesting features of NGC 6956, such as a visible Type Ia supernovawhich is the result of a white dwarf star explosion resulting from the accretion of matter from a companion star.
This type of supernova is another key way of determining the distance of distant galaxies, as astronomers can measure how fast a supernova dims to determine its distance from Earth. And while accurately filling in the galactic map is useful in itself, repeated measurements of the distance of these extragalactic objects are an important tool in understanding the current rate of expansion in the universe.
Follow us on Twitter @spacedotcom or he Facebook.
