They are very bright or luminous stars.
main-sequence stars
That's short for Hertzsprung-Russel diagram. It is a diagram in which the total luminosity versus color (and therefore temperature) of many stars is plotted.
An H-R Diagram (Hertzsprung and Russell) is used to classify stars based on their size and brightness. The main sequence stars, such as our sun, are the medium stars, and take up the middle f the diagram, while the giants and dwarves are located on either side. http://www.eso.org/public/outreach/eduoff/cas/cas2002/cas-projects/bulgaria_comaber_1/hr_local.gif <- shows what an H-R diagram looks like.
The Lepus Constellation, "Lepus" meaning 'Hare'. The formation of the quadrilateral stars is known as 'Arsh-al-Jawza'.
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 More recently, that has been replaced by the B-V colour scale.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.
The nearest stars - assuming all stars up to a certain distance are actually known - are representative of the general star population. The brightest stars are not. They are... brighter than the average stars.
One graph used to relate stars' absolute magnitudes and their spectral types is the Hertzsprung-Russell diagram, better (and more simply) known as the H-R diagram.
The HR diagram contains only stars - so everywhere.
A Hertzsprung-Russell (H-R) diagram, also known as a color-magnitude diagram, is a graph that plots stars based on their absolute magnitude (brightness) and spectral type (color). It is a valuable tool for studying the properties and evolutionary stage of stars within a specific population.
The "supergiant" stars are the brightest stars on the H-R diagram.
All stars.
It's the main sequence because on the H-R diagram most of the stars fall on or near this line.
stars there called stars
stars there called stars
main-sequence stars
A Hertzsprung-Russell diagram or H-R diagram.
The Hertzsprung-Russell diagram (H-R diagram) is a graph of stars showing the stars' luminosities or absolute magnitude versus their spectral type which is related to their effective temperature.