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| Spiral Galaxy NGC 4731 |
NGC 4731, a large and expansive spiral galaxy, is showcased in this striking image captured by the NASA/ESA Hubble Space Telescope. Located 43 million light-years away in the Virgo constellation, this galaxy has been observed using data collected from six different filters to create this incredibly detailed image. The galaxy's luminous long bar, trailing arms, dark dust lanes, bright pink star-forming regions, and billowing gas clouds are depicted with vivid details thanks to the richness of colors.
Approximately 60% of all galaxies are barred spiral galaxies, outnumbering both normal spirals and elliptical galaxies combined. The observable bar structure of the galaxy results from the aligned orbits of stars and gases, creating a dense region where individual stars come and go over time. While the process of maintaining the spiral arms of a galaxy is somewhat more mysterious when bars are involved, it still preserves them. As spiral galaxies evolve, they appear to form bars at their centers, which helps explain the abundance of bars observed today; however, if mass accumulated along the bar becomes unstable, they can also lose them. Star formation is fueled by matter and energy transported to a galaxy through orbiting models and gravitational interactions that support the bar. In fact, this movement of matter within galaxies is the focus of the NGC 4731 observation program.
The spiral arms of NGC 4731 extend far beyond the boundaries of the bar and this close-up Hubble image. It is believed that the elongated arms of the galaxy are a result of gravitational interactions with neighboring galaxies in the Virgo cluster.