The majority of the thousands of galaxies we’ve discovered in the universe fit into relatively well-defined categories: spiral galaxies like our Milky Way, tall, thin elliptical galaxies, and lenticular galaxies that lie somewhat midway between the two.
But some galaxies are anomalies that do not fit into these clear shapes, and those are called irregular galaxies. These galaxies can be chaotic and asymmetric and can be formed by gravitational forces that pull normal galaxies into strange shapes.
This week’s image from the Hubble Space Telescope shows one of these irregular galaxies called NGC 1156. It has neither the arms extending into a spiral galaxy nor the long shape of an ellipsoid, but it has the characteristics of both, Digitartlends reported.
It has thousands of bright stars with regions where stars are crowded as you’d expect to see in a spiral galaxy and the soft diffuse glow around its center suggests an oval shape. .
But NGC 1156’s unusual structure isn’t the only feature that makes it intriguing,” the Hubble scientists wrote. Close enough to affect their strange shape and ongoing star formation, the maximum energy of young, newly formed stars gives the galaxy the color, versus the red glow of ionized hydrogen gas, while its center is densely filled with older generations of stars. “
This image is an updated version with new data. Following an earlier image of the galaxy from Hubble released in 2019, a telescope like Hubble is very crowded, which means many researchers want to use it more than there is time, so every minute of observing time is precious.
However many observing programs need to use the telescope for extended periods of time, or can only be done at certain times, so there is some amount of free time when Hubble is not used for other projects when it is given to fill-in-the-blank programs like every known nearby galaxy.
This project monitors nearby galaxies such as NGC 1156 to gain more information about the type of stars within them.