Of great importance to theories of stellar evolution, it evolved from charts begun in 1911 by the Danish astronomer Ejnar Hertzsprung and independently by the U.S. astronomer Henry Norris Russell .
What is the H-R diagram based on?
Developed independently in the early 1900s by Ejnar Hertzsprung and Henry Norris Russell, it plots the temperature of stars against their luminosity (the theoretical HR diagram), or the colour of stars (or spectral type) against their absolute magnitude (the observational HR diagram, also known as a colour-magnitude ...
What is the proper name for the H-R diagram?
The Hertzsprung–Russell diagram , abbreviated as H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars’ absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
How are HR diagrams stars organized?
In an H-R diagram the luminosity or energy output of a star is plotted on the vertical axis . This can be expressed as a ratio of the star’s luminosity to that of the Sun; L * /L sun . Astronomers also use the historical concept of magnitude as a measure of a star’s luminosity.
What does an H-R diagram reveal about star types?
They can also reveal information about its temperature, motion through space, and its magnetic field strength . By plotting the stars on the H-R diagram according to their temperatures, spectral classes, and luminosity, astronomers can classify stars into their different types.
What color star is the coolest?
Red stars are the coolest. Yellow stars are hotter than red stars. White stars are hotter than red and yellow. Blue stars are the hottest stars of all.
What Cannot be determined by an H-R diagram?
Apparent magnitude depends on the intrisic brightness of a star and it’s distance. ... The life span of an individual star can be determined by noting it’s position on the H-R diagram, but the age of a particular star cannot necessarily be determined .
Which star is the hottest?
The hottest one measures ~210,000 K; the hottest known star. The Wolf-Rayet star WR 102 is the hottest star known, at 210,000 K.
Why was the H-R diagram created?
The Hertzsprung-Russell diagram is a graph that plots the temperature of a star against its absolute magnitude or luminosity . It was created by astronomers Ejnar Hertzsprung and Henry Norris Russell about 1910, and can be used to chart the life cycle or evolution of a star.
What is the star life cycle?
A star’s life cycle is determined by its mass . The larger its mass, the shorter its life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born.
Are M stars the coldest or hottest?
The spectral sequence is also a colour sequence: the O- and B-type stars are intrinsically the bluest and hottest; the M-, R-, N-, and S-type stars are the reddest and coolest .
Which star has the highest luminosity?
| Name Constellation Bolometric luminosity (Solar lum.) | Sun 1 | Alpha Centauri A Centaurus 1.519 | Sirius Canis Major 25.4 | Vega Lyra 40.12 |
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Where is Betelgeuse on the H-R diagram?
Betelgeuse in the constellation Orion — X-axis: 3000K, Y-axis 10 5 M. Polaris, the north pole star — X-axis: 6000K, Y-axis between 10 3 and 10 4 M. Sirius, the brightest star visible from Earth after the Sun — X-axis: 9000K, Y-axis 10 and 10 2 M.
Where is Sirius on the H-R diagram?
At the lower left corner of the H-R diagram are the smallest stars. Stars like Sirius B and Procyon B are just the opposite of the supergiants. They are extremely hot, dense, and dim.
Which classification of stars on the H-R diagram are the oldest?
In the image above, you can see a schematic HR diagram with plots of lines that represent the Main Sequence for a number of open clusters. From the location of the Main Sequence Turn-Off, you can see that NGC 2362 is the youngest, then h & χ Persei, and M67 is the oldest of the clusters.
