Using the NASA/ESA Hubble Space Telescope, astronomers observed seven interacting galaxies with long tadpole-like tidal tails of gas, dust, and numerous stars. Hubble’s exquisite clarity and sensitivity to ultraviolet light led to the discovery of 425 clusters of newborn stars along these tidal tails. Each cluster contains up to a million newborn blue stars.
As seen in this Hubble image, galaxy AM 1054-325 has been distorted from its usual pancake-like spiral shape into an S-shape by the gravity of its neighboring galaxies. As a result, clusters of newborn stars form along tidal tails stretching across thousands of light years, resembling strings of pearls. Image credit: NASA/ESA/STScI/Jayanne English, University of Manitoba.
Tidal tail star clusters have been known for decades. When galaxies interact, gravitational tidal forces pull out long streams of gas and dust.
Two commonly used examples are antennas and rat galaxy It has elongated finger-like projections.
In a new study, astronomer Michael Rodrak of Randolph-Macon College and his colleagues combined new observational data with archival data to determine the age and mass of the tidal tail cluster.
Researchers discovered that these star clusters are very young, only 10 million years old.
And they appear to be forming at the same rate along a tail that extends over thousands of light years.
“It’s surprising that there are so many young objects in the tail,” said Dr Rodrak, lead author of the paper. paper Published in Royal Astronomical Society Monthly Notices.
“It tells us a lot about cluster formation efficiency.”
“With tidal tails, a new generation of stars will be built that otherwise would not exist.”
Tidal tails look like spiral arms of galaxies extending into space.
The outer part of the arm is pulled like taffy by the gravitational tug of war between a pair of interacting galaxies.
Before the merger occurred, galaxies may have been rich in dusty clouds of hydrogen molecules that simply remained inert.
However, during the encounter, the clouds swayed and clashed.
This compressed the hydrogen and triggered the firestorm of star birth.
“The fate of these strung star clusters is uncertain,” the astronomers said.
“They remain intact under gravity and can evolve into globular clusters that orbit outside the plane of the Milky Way.”
“Alternatively, they could disperse and form a stellar halo around their host galaxy, or be thrown off and become stars that wander between galaxies.”
“This pearly star formation may have been more common in the early Universe, when galaxies were colliding with each other more frequently.”
“These nearby galaxies observed by Hubble are proxies for what happened in the distant past, and are therefore laboratories for studying the distant past.”
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michael rodrak other. 2023. Star clusters in tidal dust. MNRAS 526 (2): 2341-2364; doi: 10.1093/mnras/stad2886
Source: www.sci.news
