Period-Luminosity Relation in Variable Stars: Cepheids and RR Lyrae #302944 (License: Personal Use)

The graph displays the period-absolute magnitude relation for three types of pulsating variable stars: classical (Type I) Cepheids, Type II Cepheids, and RR Lyrae stars. Each class follows a distinct linear trend on a log-period vs. absolute magnitude plot, with classical Cepheids being the most luminous and RR Lyrae the faintest. The example point for δ Cephei anchors the classical Cepheid sequence near 5.4-day period and M ≈ -3.5.

Used in astronomy education, research papers, and cosmology resources to explain standard candles and the cosmic distance ladder; targets students, educators, and researchers seeking to understand stellar pulsation and distance measurement techniques.