Editing Star cluster (section)

==Astronomical significance==
[[File:Artist's impression of an exoplanet orbiting a star in the cluster Messier 67.jpg|thumb|Artist's impression of an exoplanet orbiting a star in the cluster [[Messier 67]]<ref>{{cite news|title=First Planet Found Around Solar Twin in Star Cluster|url=https://www.eso.org/public/unitedkingdom/news/eso1402/|access-date=2017-11-27|newspaper=ESO Press Release|url-status=live|archive-url=https://web.archive.org/web/20171201035459/https://www.eso.org/public/unitedkingdom/news/eso1402/|archive-date=2017-12-01}}</ref> ]]

Star clusters are important in many areas of astronomy. The reason behind this is that almost all the stars in old clusters were born at roughly the same time.<ref>{{Citation |chapter=The Food of the Stars |date=2013-10-01 |pages=34 |chapter-url=https://www.degruyter.com/document/doi/10.4159/harvard.9780674423770.c3/html |access-date=2024-06-18 |publisher=Harvard University Press |language=en |doi=10.4159/harvard.9780674423770.c3 |isbn=978-0-674-42377-0 |title=Stars and Clusters }}</ref> Various properties of all the stars in a cluster are a function only of mass, and so stellar evolution theories rely on observations of open and globular clusters. This is primarily true for old globular clusters. In the case of young (age < 1Gyr) and intermediate-age (1 < age < 5 Gyr), factors such as age, mass, chemical compositions may also play vital roles.<ref>{{Citation |title=All the World's a Stage–The Galaxy |date=2013-10-01 |pages=6–7 |url=https://www.degruyter.com/document/doi/10.4159/harvard.9780674423770.c1/html |access-date=2024-06-18 |publisher=Harvard University Press |language=en |doi=10.4159/harvard.9780674423770.c1 |isbn=978-0-674-42377-0|url-access=subscription }}</ref> Based on their ages, star clusters can reveal a lot of information about their host galaxies. For example, star clusters residing in the Magellanic Clouds can provide essential information about the formation of the Magellanic Clouds dwarf galaxies. This, in turn, can help us understand many astrophysical processes happening in our own Milky Way Galaxy. These clusters, especially the young ones can explain the star formation process that might have happened in our Milky Way Galaxy.

Clusters are also a crucial step in determining the [[Distance ladder|distance scale of the universe]]. A few of the nearest clusters are close enough for their distances to be measured using [[parallax]]. A [[Hertzsprung–Russell diagram]] can be plotted for these clusters which has absolute values known on the [[luminosity]] axis. Then, when similar diagram is plotted for a cluster whose distance is not known, the position of the [[main sequence]] can be compared to that of the first cluster and the distance estimated. This process is known as main-sequence fitting. [[Extinction (astronomy)|Reddening]] and [[stellar population]]s must be accounted for when using this method.

Nearly all stars in the Galactic field, including the Sun, were initially born in regions with embedded clusters that disintegrated. This means that properties of stars and planetary systems may have been affected by early clustered environments.<ref>{{Cite journal |last1=Winter |first1=Andrew J. |last2=Kruijssen |first2=J. M. Diederik |last3=Longmore |first3=Steven N. |last4=Chevance |first4=Mélanie |date=2020-10-22 |title=Stellar clustering shapes the architecture of planetary systems |journal=Nature |language=en |volume=586 |issue=7830 |pages=528–532 |doi=10.1038/s41586-020-2800-0 |issn=0028-0836 |pmc=7116760 |pmid=33087913|arxiv=2010.10531 |bibcode=2020Natur.586..528W }}</ref> This appears to be the case for our own [[Solar System]], in which chemical abundances point to the effects of a supernova from a nearby star early in our Solar System's history.