Stellarmass

Stellarmass is a fundamental property describing the amount of matter contained in a star. It is most commonly expressed in solar masses (M☉), where 1 M☉ equals the mass of the Sun. Stellarmass values range from about 0.08 M☉, near the lower limit for sustained hydrogen fusion, to around 150 M☉ for the most massive stars observed, though the upper bound remains uncertain and environment-dependent. Mass strongly influences a star’s luminosity, temperature, and lifetime.

Measuring stellarmass relies on both observations and models. In binary systems, orbital dynamics yield dynamical masses directly; eclipsing binaries provide particularly precise measurements. For single stars, masses are inferred from luminosity, effective temperature, and radius with theoretical models, while asteroseismology analyzes oscillations to constrain mass. Spectroscopic gravity (log g) and radius estimates can also be used, albeit with larger uncertainties.

On the main sequence, luminosity scales steeply with mass—roughly L ∝ M^3–4 for sun-like stars—so stellarmass is a primary determinant of a star’s brightness and color. Mass loss through stellar winds, pulsations, and eruptions can gradually reduce a star’s mass, especially for high-mass stars during evolution, altering its subsequent evolution and end state.

The fate of a star is closely tied to its initial stellarmass. Low-mass stars (roughly up to 8–10 M☉) end life as white dwarfs after shedding envelopes. More massive stars undergo core-collapse and typically leave neutron stars or black holes; very massive stars may experience pair-instability or direct collapse. The distribution of stellar masses at birth, the initial mass function, shapes the evolution of galaxies and the chemical enrichment of the universe.