Solar mass
The solar mass is a unit of mass equal to the Sun’s mass, used chiefly to express the masses of stars, black holes, and other astronomical objects.
Stellar mass: The mass of a star, usually expressed in solar masses in astronomy. This is the quantity most commonly reported using the solar-mass unit.
Sun: The star at the center of the Solar System, whose gravity binds the planets and smaller bodies. Its mass supplies the unit’s defining reference.
Newton's law of universal gravitation: A law stating that two masses attract with a force proportional to their product and inversely proportional to distance squared. It connects the Sun’s gravitational influence to its measured mass.
Arthur Eddington: A British astrophysicist who helped establish modern theories of stellar structure and the relation between stellar mass and luminosity. His work helped make stellar masses central to quantitative astrophysics.
Chandrasekhar limit: The maximum mass, about 1.4 solar masses, of a stable white dwarf supported by electron degeneracy pressure. Its value shows how the unit marks a decisive limit in stellar evolution.
Gravitational constant: The proportionality constant in Newton’s law of universal gravitation and Einstein’s field equations. Its uncertainty affects the conversion between solar mass and kilograms.
Solar mass parameter: The product of the gravitational constant and the Sun’s mass, measured more precisely than either quantity separately. This parameter underlies modern high-precision solar-mass conventions.
Stellar structure: The internal arrangement and physical state of a star, governed by gravity, pressure, energy transport, and nuclear reactions. The solar mass became a natural benchmark as models compared stars with the Sun.
Tolman–Oppenheimer–Volkoff limit: The maximum mass of a neutron star supported against gravitational collapse by pressure and nuclear forces. Neutron-star mass estimates in solar masses test where this uncertain threshold lies.
Kilogram: The SI base unit of mass, defined by fixing the numerical value of the Planck constant. Solar mass connects astronomical measurements to this standard mass unit.