main sequence
Quick Summary
The main sequence is a band on a graph that includes about 90 percent of all star types. Stars spend the majority of their active lives on the main sequence, fusing hydrogen into helium in their cores. This process releases energy, creating an outward pressure that balances the inward pull of gravity, stabilizing the star.123
The duration a star remains on the main sequence depends on its mass. More massive stars burn their hydrogen fuel much faster, leading to shorter lifespans, while less massive stars can stay on the main sequence for billions or even trillions of years. When a star exhausts its core hydrogen, it leaves the main sequence and evolves into a red giant or supergiant. The Sun, for example, is a main-sequence star classified as G2 V.4235
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star clusterGlobular clusters…of stars along the lower main sequence, with a giant branch containing more-luminous stars curving from there upward to the red and with a horizontal branch starting about halfway up the giant branch and extending toward the blue.
Read More…of stars along the lower main sequence, with a giant branch containing more-luminous stars curving from there upward to the red and with a horizontal branch starting about halfway up the giant branch and extending toward the blue.
Read More- star clusterDynamics of star clusters
Older clusters, whose main sequence does not reach to the blue stars, show no correlation with spiral arms because in the intervening years their motions have carried them far from their place of birth.
Read MoreOlder clusters, whose main sequence does not reach to the blue stars, show no correlation with spiral arms because in the intervening years their motions have carried them far from their place of birth.
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Hertzsprung-Russell diagramThe group called the main sequence extends in a rough diagonal from the upper left of the diagram (hot, bright stars) to the lower right (dim and cool). Large, bright, though cool, stars called giants and supergiants appear in the upper right, and the white dwarfs, dim, small, and…
Read MoreThe group called the main sequence extends in a rough diagonal from the upper left of the diagram (hot, bright stars) to the lower right (dim and cool). Large, bright, though cool, stars called giants and supergiants appear in the upper right, and the white dwarfs, dim, small, and…
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starHertzsprung-Russell diagram…a diagonal line called the main sequence. These stars range from hot, O- and B-type, blue objects at least 10,000 times brighter than the Sun down through white A-type stars such as Sirius to orange K-type stars such as Epsilon Eridani and finally to M-type red dwarfs thousands of times…
Read More…a diagonal line called the main sequence. These stars range from hot, O- and B-type, blue objects at least 10,000 times brighter than the Sun down through white A-type stars such as Sirius to orange K-type stars such as Epsilon Eridani and finally to M-type red dwarfs thousands of times…
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