2. If the sun is not counted, the nearest star is proxima centauri (αC Centauri), which is a red dwarf star with magnitude 10.6. It is 420 light years away from us, which is equivalent to 264,600 astronomical units (one light year is equivalent to 63,000 astronomical units), which is 264,600 times the distance from the earth to the sun.
Extended data:
The star is a spherical luminous plasma condensed by gravity, and the sun is the closest star to the earth. Almost all the stars that can be seen at other nights on earth are in the Milky Way, but because of their long distance, these stars seem to be just fixed luminous points. Historically, those prominent stars have formed constellations and clusters, and the brightest stars have their own traditional names. The catalogue of stars compiled by astronomers provides many standards for the naming of different stars.
At least during the life of a star, the star will undergo a nuclear fusion reaction in which hydrogen is fused into helium at the core, transfer energy from the inside of the star, travel a long distance, and then radiate from the surface to outer space. Once the hydrogen in the core is exhausted, the life of a star will be over. Some stars will undergo the process of stellar nucleus synthesis before the end of life; Some stars will undergo supernova nuclear synthesis before explosion, which will produce almost all natural elements heavier than helium. At the end of life, stars also contain degraded matter.
Astronomers can learn about the mass, age, chemical element abundance and many other properties of stars by observing their motion, brightness and spectrum. The total mass of a star is the main factor that determines its evolution and ultimate fate: a star, including its diameter, temperature and other characteristics, will change at different stages of its life, and its surrounding environment will affect its rotation and movement. A chart depicting the temperature relative to the brightness of many stars, that is, the H-R chart, enables us to measure the age and evolution of stars.
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