The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars.
Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body).
Circumstellar dust is cosmic dust around a star.
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output.
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
Radiative flux, also known as radiative flux density or radiation flux, is the amount of power radiated through a given area, in the form of photons or other elementary particles, typically measured in W/m2.
A spectral energy distribution (SED) is a plot of energy versus frequency or wavelength of light (not to be confused with a 'spectrum' of flux density vs frequency or wavelength).
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
Young stellar object (YSO) denotes a star in its early stage of evolution.