![]() In particular, by plotting a HR diagram for either a globular or open cluster of stars, astronomers can estimate the age of the cluster from where stars appear to turnoff the main sequence (see the entry on main sequence for how this works). The Sun is found on the main sequence with a luminosity of 1 and a temperature of around 5,400 Kelvin.Īstronomers generally use the HR diagram to either summarise the evolution of stars, or to investigate the properties of a collection of stars. These stars are very hot but have low luminosities due to their small size. white dwarf stars (luminosity class D) are the final evolutionary stage of low to intermediate mass stars, and are found in the bottom left of the HR diagram.Stars enter this evolutionary stage once they have exhausted the hydrogen fuel in their cores and have started to burn helium and other heavier elements. They have low surface temperatures and high luminosities which, according to the Stefan-Boltzmann law, means they also have large radii. red giant and supergiant stars (luminosity classes I through III) occupy the region above the main sequence.Main sequence stars have a Morgan-Keenan luminosity class labelled V. It is here that stars spend about 90% of their lives burning hydrogen into helium in their cores. The main sequence stretching from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) dominates the HR diagram.The HertzsprungRussell diagram (abbreviated as HR diagram, HR diagram or HRD) is a scatter plot of stars showing the relationship between the stars absolute magnitudes or luminosities versus. There are 3 main regions (or evolutionary stages) of the HR diagram: The Sun is found on the main sequence at luminosity 1 ( absolute magnitude 4.8) and BV color index 0.66 (temperature 5780 K, spectral type G2V). Also plotted are the Morgan-Keenan luminosity classes that distinguish between stars of the same temperature but different luminosity. The giant branch is also well populated and there are many white dwarfs. A one-solar-mass white dwarf is about the. By far the most prominent feature is the main sequence, which runs from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) of the diagram. Largest Diameter - main-sequence star of spectral type A - Jupiter - one-solar-mass white dwarf - the moon - a two-solar-mass neutron star - the event horizon of a two-solar-mass black hole Smallest Diameter Feedback: Correct The main-sequence star is obviously much larger than a planet such as Jupiter. This Hertzsprung-Russell diagram shows a group of stars in various stages of their evolution. The giant branch and supergiant stars lie above the main sequence, and white dwarfs are found below it. By far the most prominent feature is the main sequence (grey), which runs from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) of the diagram. The Hertzsprung-Russell diagram the various stages of stellar evolution. ![]()
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