In earlier Hertzsprung-Russell diagrams, the colours, as defined by the horizontal axis, showed the spectral type of the stars. This was an ordinal scale, not an exact numerical scale. The ordering was according to the surface temperature of the stars.
More recently, that has been replaced by the B-V colour scale. This is based on UBV photometry, where the amount of light given out by stars is measured in the ultraviolet (wavelength = 364 nm), blue (442 nm), and visual (540 nm) regions of the spectrum.
The value of V is subtracted from B and this is the B-V colour index which is used to colour-code stars. As a star gets cooler and therefore more red, the B-V colour index increases. Hot stars have a small B-V and cool stars have a large B-V.
main-sequence stars
a picture or diagram
Perhaps you mean the Venn diagram.
The answer will depend on who you mean by HE.The answer will depend on who you mean by HE.The answer will depend on who you mean by HE.The answer will depend on who you mean by HE.
Does it Mean like if u add the ratios like 2 to 3
The HR Diagram depicts the relationship between a star's luminosity (brightness) and temperature. Stars appear in different colors on the diagram, ranging from hot blue stars to cool red stars. The main sequence runs from hot, blue stars in the upper left to cool, red stars in the lower right.
The HR diagram contains only stars - so everywhere.
Of course they are on the HR diagram. They are simply not on the main sequence.
HR diagram
The red dwarves.
Up at the top right. If you look on the Australian Telescope National facility website, their HR diagram shows this clearly.
The Hertzsprung-Russell diagram helps scientists understand the life cycle of stars by showing the relationship between a star's luminosity and temperature. It enables astronomers to classify stars based on their evolutionary stage and predict their future evolution. This diagram is essential for studying the properties and behavior of stars within galaxies.
All stars.
its located somewhere
Slightly to the right of centre on the main sequence. If you look on the Australian Telescope National facility website, their HR diagram shows the position of the sun.
Its called an HR diagram or a Hertzsprung-Russell diagram.
Black dwarfs are not on the Hertzsprung-Russell diagram because they are theoretical end points in stellar evolution where white dwarfs cool down to become invisible. Their low temperature and luminosity levels make them undetectable in the visible spectrum, so they do not appear on the HR diagram.