hoofdreeksster

Hoofdreeksster is the Dutch term for a main-sequence star, a star that fuses hydrogen into helium in its core and lies on the main sequence of the Hertzsprung–Russell diagram. These stars are in a long-lived, stable phase where hydrostatic equilibrium maintains their size and brightness.

Main-sequence stars span a wide range of masses and temperatures, from about 0.08 to over 100 solar masses and from roughly 3,000 to 40,000 kelvin. Their spectra follow a broad sequence from hot, blue O-type stars to cool, red M-type stars. Luminosity increases steeply with mass, so more massive main-sequence stars shine much brighter and have shorter lifetimes.

Lifespan on the main sequence depends primarily on mass. Lower-mass stars burn hydrogen slowly and can remain on the main sequence for tens to hundreds of billions of years, while the most massive stars survive only a few million years. When core hydrogen is exhausted, a main-sequence star evolves off the sequence, becoming a giant or supergiant, and ends its life in various ways depending on mass—leaving behind a white dwarf, or collapsing in a supernova to form a neutron star or black hole.

In observations, main-sequence stars define a characteristic band on the Hertzsprung–Russell diagram and follow the mass–luminosity relation. The Sun is the prototypical example of a G-type main-sequence star. In Dutch astronomy, hoofdreeksster remains the standard term for this stellar class, translated in English as main-sequence star.