Lecture
This lecture explores extrinsic stellar variability, focusing on the luminosity and surface temperature of different types of stars, the color-magnitude diagram, and the quantification of variability in eclipsing binary star systems. It delves into the history of the study of double stars, the detection of stellar multiplicity, and the diversity of eclipsing systems. The lecture also covers the concepts of microlensing, astrometric binaries, and the detection of extrasolar planets through gravitational microlensing.