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You are watching: Which of the following luminosity classes refers to stars on the main sequence?

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The Hertzsprung-Russell chart (HR diagram) is just one of the most vital tools in the examine of stellar evolution. Occurred independently in the early 1900s through Ejnar Hertzsprung and Henry Norris Russell, that plots the temperature that stars versus their luminosity (the theoretical HR diagram), or the colour of stars (or spectral type) versus their pure magnitude (the observational HR diagram, additionally known together a colour-magnitude diagram).Depending on its early mass, every star go through details evolutionary step dictated through its inner structure and how it produces energy. Each of this stages synchronizes to a readjust in the temperature and also luminosity of the star, which can be seen to relocate to various regions ~ above the HR diagram together it evolves. This reveals the true strength of the HR chart – astronomers deserve to know a star’s internal structure and evolutionary stage merely by determining its place in the diagram.

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The Hertzsprung-Russell diagram the miscellaneous stages of mainly evolution. By far the most prominent function is the key sequence (grey), which operation from the top left (hot, luminous stars) to the bottom right (cool, pass out stars) the the diagram. The large branch and supergiant stars lie over the key sequence, and white dwarfs are found listed below it.Credit: R. Hollow, CSIRO.


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This Hertzsprung-Russell diagram reflects a team of stars in miscellaneous stages of your evolution. By far the many prominent function is the main sequence, which operation from the upper left (hot, luminous stars) to the bottom ideal (cool, pass out stars) of the diagram. The huge branch is also well populated and also there are plenty of white dwarfs. Likewise plotted are the Morgan-Keenan luminosity classes the distinguish between stars the the very same temperature however different luminosity. -->There room 3 key regions (or evolutionary stages) the the HR diagram:

The sun is uncovered on the main sequence through a luminosity the 1 and a temperature of roughly 5,400 Kelvin.Astronomers normally use the HR diagram to one of two people summarise the development of stars, or to inspection the properties of a collection of stars. In particular, by plot a HR diagram because that either a globular or open cluster of stars, astronomers deserve to estimate the age of the cluster from wherein stars show up to turnoff the main sequence (see the entry on main sequence for exactly how this works).