How is stellar mass reliably inferred by astronomers?
By observing the gravitational effects a star has on other objects, often using binary systems
Stellar mass, which governs a star's entire existence, cannot typically be measured directly like weighing an object in a lab. Instead, mass determination relies heavily on inferring gravitational influence. The most reliable method involves observing systems where a star is gravitationally bound to another object, such as a companion star in a binary system or orbiting planets. By precisely measuring the period of the orbit and the size (semi-major axis) of that orbit, astronomers can apply Kepler's Third Law, adapted for the masses involved. This physical interaction provides the necessary data to calculate the mass, often expressed conveniently in units of solar mass ($M_ ext{odot}$).
