Sternwinden

Sternwinden, known in English as stellar winds, are continuous outflows of gas and plasma ejected from stars into the surrounding interstellar medium. They vary widely in speed, mass-loss rate, and composition, depending on stellar type and evolutionary stage. The Sun’s wind is the best-studied example, but Sternwinden encompass winds from hot O- and B-type stars as well as cool giants and evolved stars.

The mechanisms driving Sternwinden differ by star. Hot, luminous stars generate fast winds with speeds of roughly 1000 to 3000 km/s, driven by radiation pressure on ions. Cooler giants and asymptotic-giant-branch stars produce slower, denser winds, often aided by pulsations and dust formation. The solar wind is a magnetized, magnetically structured outflow, with occasional episodic enhancements such as coronal mass ejections.

Detection and measurement rely on indirect methods. Spectral line profiles, including P Cygni features, reveal outflow velocities; X-ray and radio observations help probe hot, ionized components; and in some cases, astrospheric absorption provides momentum estimates. Mass-loss rates span several orders of magnitude, from about 10^-14 M☉/yr for the Sun to 10^-5 M☉/yr or more for the strongest winds of massive stars, with composition reflecting stellar origin and metallicity.

Sternwinden influence the evolution of galaxies and planetary systems. They carve wind-blown bubbles in the interstellar medium, inject energy and newly synthesized elements, and can alter star formation in surrounding clouds. They also affect exoplanetary atmospheres and habitability through particle and radiation environments.

Historically, the concept developed from early spectroscopic and theoretical work, culminating in a detailed solar-wind model and later broader stellar-wind studies. Current research focuses on mass-loss rates, wind structure, and the impact on cosmic evolution.