Hertzsprung-russell Diagram

In short, the Hertzsprung - Russell diagram or H - R chart is a chart that plots stars based on temperature and absolute values. This figure actually shows a very interesting pattern. The H - R map was named after two astronomers, Ejnar Hertzsprung and Henry Russell who discovered the star pattern. Two astronomers have independently discovered that when comparing the size and spectral class (color) of the stars, we can obtain much information about them. The main purpose of the H - R diagram is to show the relationship between temperature and the absolute size of stars. The type of temperature measurement used is Kelvin and the zero point is equal to -273.16 ° C

In the HR chart, the temperature range of Kelvin is 3,000 to 30,000. The absolute size of the star on the H - R map is in the range of +15 to - 10. The absolute size is the brightness of the star when they are 32.6 light years away from the earth. On this scale, the smaller the number, the brighter the star. Therefore, the absolute value of -10 is much brighter than a star with an absolute value of +15.

After creating the chart, two astronomers discovered many patterns. They found that 90% of the stars are within the middle range of the chart. These stars are the range of hot, bright, blue stars in the upper left corner of the H - R diagram from the cool tones, dark red, red stars in the lower right corner of the H - R diagram. The star entering this band is called the main sequence star. A star like the sun, and almost all the beginnings that can be seen in the night sky are within range of this main sequence star. There is another cool and bright star near the upper right corner of the H - R map.

These stars are very big and therefore have a very large surface area. These large surface areas emit lots of light, which makes the stars brighter. Most of these stars are called red giants. Some are so big that they are called super giants. The temperature of the red giant is about 3,500 degrees Kelvin, the absolute value is about 0. The super star temperature is about 3000 degrees Kelvin, the absolute value is about -7.

The Hertzsprung-Russell plot (HR graph) is a large sample of a star plot that plots visual absolute values ​​based on color index. Color index B - V is the difference between the size of the blue light star or B and the size of the visible light (green - yellow) or V. A large positive value indicates the temperature of a red star with a cold surface, and a negative value indicates a hot blue star. When stars near the sun are drawn on the HR chart, the distributions of various masses, age, and constellation stars are displayed. Many stars are relatively close to the slope curve, and as star heat gets bigger, it is called main sequence star. However, the graph usually includes stars away from the main sequence curve at the latter stage of evolution.

Hertzsprung - Russell plot or H - R plot is a plot of stellar luminosity versus surface temperature. Most of the stars are located on the main line, extending from the high temperature high brightness to the low temperature low brightness obliquely from the H - R chart. The position of the star along the main sequence is determined by its quality. A high-quality star will emit more energy than a low-mass star of the main line and it will be hotter. The main sequence star gains energy from the fusion of protons and scorpions. About 90% of the stars are in the main line. Only about 10% of stars are white dwarfs, less than 1% are superstars or superstars.

Hertzsprung-Russell As shown in the figure, the main sequence star has a wide range of intensity and color that can be classified according to these characteristics. The smallest star known as a red dwarf contains only 10% of the mass of the sun, it releases only 0.01% of the energy and can not emit light at temperatures between 3000 and 4000 K. Despite its small nature, red dwarfs are by far the largest number of stars in the universe and have a lifetime of hundreds of billions of years. On the other hand, the mass of the largest star called supergiant is more than 100 times the mass of the sun, the surface temperature exceeds 30,000 K. A million years. These extreme stars are thought to be common in the early universe but today they are very rare - the entire galaxy contains just a few supergiants