An international team led by Australian research centre ASTRO 3D reports that age is the driving force in changing how stars move within galaxies.
Galaxies start life with their stars rotating in an orderly pattern but in some the motion of stars is more random. Until now, scientists have been uncertain about what causes this – possibly the surrounding environment or the mass of the galaxy itself.
A new study, published in a paper today in MNRAS (Monthly Notices of the Royal Astronomical Society), has found that the most important factor is neither of these things. It shows the tendency of the stars to have random motion is driven mostly by the age of the galaxy – things just get messy over time.
“When we did the analysis, we found that age, consistently, whichever way we slice or dice it, is always the most important parameter,” says first author Prof Scott Croom, an ASTRO 3D researcher at the University of Sydney.
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