O−C diagram of two stars in M 5 cluster, Variable 19 and Variable 70. Dots show observational data, lines show fitted function of O−C in units of variability period vs time. Period of Variable 19 changed abruptly in 1947, period of Variable 70 lengthened uniformly with time.
<a href="//commons.wikimedia.org/wiki/User:Vallastro" title="User:Vallastro">Vallastro</a>
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<span class="int-own-work" lang="en">Own work</span>