A stellar wind is a flow of neutral or charged gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric. Different types of stars have different types of stellar winds. Post-main sequence stars nearing the ends of their lives often eject large quantities of mass in massive ( solar masses per year), slow (v = 10 km s − 1) winds. These include red giants and supergiants, and asymptotic giant branch stars. These winds are likely to be driven by radiation pressure on dust condensing in the upper atmosphere of the stars. G stars like the Earth\'s Sun have a wind driven by their hot, magnetized corona. The Sun\'s wind is called the solar wind. These winds consist mostly of high-energy electrons and protons (about 1 keV) that are able to escape the star\'s gravity because of the high temperature of the corona. ...more

Life history of a star, beginning with its condensation out of the interstellar gas (see interstellar matter) and ending, sometimes catastrophically, when the star has exhausted its nuclear fuel or can no longer adjust itself to a stable configuration. Because a star\'s total energy reserve is finite, a star shining today cannot continue to produce its present luminosity steadily into the indefinite future, nor can it have done so from the indefinite past. Thus, stellar evolution is a necessary consequence of the physical theory of stellar structure, which requires that the luminosity, temperature, and size of a star must change as its chemical composition changes because of thermonuclear reactions.

It is a gacious emission from the star\'s atmosphere.