When galaxies collide, their stars are not actually destroyed. These rough-and-tumble dynamics actually trigger the formation of new generations of stars, and potentially even planets to accompany them.
[Related: Behold six galactic collisions, masterfully captured by Hubble.]
Astronomers using the Hubble Space Telescope have taken a closer look at 12 of these interacting galaxies. These galaxies all have long tails of gas, dust, and multitudes of stars. Hubble can detect ultraviolet light and has uncovered 425 clusters of newborn stars located along these galactic tails that resemble a string of lights or pearls. Each of these clusters is packed with as many as one million newborn blue stars. The findings were described in a study published in the Monthly Notices of the Royal Astronomical Society in September 2023. A new image of the string of pearls galaxy (Galaxy AM 1054-325) was released by NASA on February 8.
Galactic collisions and high pressure
When galaxies interact with each other, gravitational tidal forces will pull out long streams of gas and dust from the material that make up each galaxy. The Antennae and Mice galaxies have long, narrow, finger-like tendrils and are common examples of what these galactic tails look like.
“As galaxies merge, clouds of gas collide and collapse, creating a high-pressure environment where stars could form,” study co-author and Penn State University astronomer Jane Charlton said in a statement. “The interiors of these mergers have been well studied, but less was known about possible star formation in the debris that results from these mergers, such as in the tidal tails.”
Tails of young stars
In their study, a team of scientists used new observations and archival data to estimate the ages and masses of tidal tail star clusters. At only 10 million years old, these clusters are very young and appear to be forming at the same rate along tails that stretch for thousands of…
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