W Ursae Majoris variable

W Ursae Majoris variables are the most common variable stars in the present day Universe.

It has since become the prototype and eponym for a class of variable stars called W Ursae Majoris variables.

A W Ursae Majoris variable is a type of eclipsing binary variable star.

Epsilon Coronae Australis is the brightest example of a W Ursae Majoris variable in the southern sky.

Epsilon Coronae Australis is an eclipsing binary belonging to a class of stars known as W Ursae Majoris variables.

Epsilon Coronae Australis is an W Ursae Majoris variable, indicating that it has a contact companion within the Roche Limit of the primary.

This distinguishes them from the so-called beta Lyrae variables and W Ursae Majoris variables, where the two components are so close that gravitational effects lead to serious deformations of both stars.

Almost all known contact binary systems are eclipsing binaries; eclipsing contact binaries are known as W Ursae Majoris variables, after their type star, W Ursae Majoris.

On the other hand, beta Lyrae variables look a bit like W Ursae Majoris variables; however, the latter are in general yet closer binaries (so-called contact binaries), and their component stars are mostly lighter than the beta Lyrae system components (about one solar mass).