Massivestar

Massivestar is an informal term used to describe stars that are significantly more massive than the Sun. In practice, astronomical usage varies: many definitions place the lower bound around 8–10 solar masses, while those labeled as very massive may begin above 20–30 solar masses. The term is less standardized than “massive star” and does not denote a formal, universally recognized category in stellar astrophysics.

Formation and structure: Like other massive stars, massivestars form in dense molecular clouds where rapid accretion builds up a large core. They reach the main sequence while still accreting material and burn hydrogen primarily through the CNO cycle. Their high luminosities exert strong radiation pressure, and they are typically hot, blue, and short-lived. As they evolve, some becomes Wolf–Rayet stars, characterized by powerful winds and exposed helium- and heavier-element layers.

Evolution and endpoints: Massive stars have brief lifetimes, lasting only a few million years. They lose substantial mass through intense stellar winds and eruptive events, contributing to chemical enrichment of their environments. The usual end state is a core-collapse supernova (Type II or, for stripped-envelope cases, Type Ib/c), leaving a neutron star or black hole. In the most massive cases and under particular conditions (often low metallicity), pair-instability processes can disrupt the star entirely in a pair-instability supernova.

Observations and significance: Massive stars strongly influence their host galaxies through ionizing radiation, winds, and supernovae, driving feedback and shaping star formation. They are studied in young star clusters and associations, with diagnostics provided by spectroscopy and multi-wavelength photometry and by distance estimates from parallaxes and cluster methods.