cluster variable

plural cluster variables

1. astronomyan 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

   3 more examples

   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, page 160

   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.

   1950, Leaflet

   There are some thirty classical Cepheids, and a few irregular variables, in the globular clusters among the stars brighter than the typical cluster variable.

   1949, Popular Astronomy

2. cluster analysisA 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, Cluster Analysis