CES2108a Diagram illustrating how concave mirrors, like those used in reflector telescopes, gather light. Viewing methods used with reflecting telescopes. C. Newtonian method. CES2111 Comparison of the light-gathering ability of two lenses. CES2118 Diagram of solar structure in cutaway view.
Binary stars orbit each other around their common center of mass.
For stars of equal mass, the center of mass lies exactly halfway between them. If one star is twice as massive as its companion, it is twice as close to their common center of mass. Therefore, more massive stars have proportionately smaller orbits than their less massive companions. CES2205 Idealized Hertzsprung-Russell diagram on which stars are plotted according to temperature and absolute magnitude. CES2211 Diagram of stellar evolution on H-R diagram for a star about as massive as the sun.