cluster variable

Noun

1. an RR Lyrae variable; a type of variable star commonly (but not exclusively) found in globular clusters
   • This period, which is exceptionally long for a cluster variable, satisfies the observations fairly well except in a few cases. - 1902, Solon Irving Bailey, A Discussion of Variable Stars in the Cluster [omega] Centauri:
   • It is a good example of a cluster variable having a large range of variations, a short period, and extremely rapid increase and decrease in light. - 1913, Solon Irving Bailey, Variable Stars in the Cluster Messier 3,...
   • Nearly all of the variable stars found in the other globular clusters had the same characteristics as those found in Omega Centauri. It was five years before a cluster variable was found outside of a globular cluster. -...
2. A variable whose values are used to classify data points into clusters; a variable that identifies one of the defining properties of clusters.
   • The first model includes the potential cluster variable conditioned on clustering variables already selected, while in the second model the variable is not included. - 2011, Sabine Landau, Morven Leese, Daniel Stahl,...