<ul><li>Astronomers using the Hubble Space Telescope (HST) have studied one of the largest young star clusters in our galaxy, Westerlund 1.</li><li>The cluster is not perfectly round, but stretched out in a northeast-southwest direction, with an eccentricity of 0.71.</li><li>Westerlund 1 has a velocity dispersion lower than expected, suggesting it formed with high efficiency or experienced minimal disruption after its birth.</li><li>The study provides important insights into the evolution and formation history of massive young star clusters, supporting the idea of mass segregation.</li></ul>

Hubble reveals key details about a massive star cluster

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