SOLAR SYSTEM

Detailed explanation-1: -The upper left corner of an HR diagram includes the hot, bright, blue stars. The coolest stars are much fainter than the hot stars, and they lie at the lower right. The band connecting the hot, bright stars at the upper left to the cool, faint stars at the lower right is called the Main Sequence.

Detailed explanation-2: -The effective temperature of a star is plotted on the horizontal axis of an H-R diagram . One quirk here is that the temperature is plotted in reverse order, with high temperature (around 30, 000-40, 000 K) on the left and the cooler temperature (around 2, 500 K) on the right.

Detailed explanation-3: -The main spectral classes in order from hottest to coolest are O, B, A, F, G, K, and M. These classes have particular colors. Spectral type is most often written across the top of the H-R diagram going from hot, bluer “O” stars on the left to cool, more red “M” stars on the right.

Detailed explanation-4: -At the top end of the main sequence, the stars are large, hot, and very luminous. Because of their size and color, they are referred to as blue giants.

Detailed explanation-5: -The group called the main sequence extends in a rough diagonal from the upper left of the diagram (hot, bright stars) to the lower right (dim and cool). Large, bright, though cool, stars called giants and supergiants appear in the upper right, and the white dwarfs, dim, small, and hot, lie in the lower left.

Detailed explanation-6: -Because of their cooler temperatures, they must be large to be as luminous as they are. The stars in the lower left of the diagram are called white dwarfs. They are very hot, but their luminosities are low, so they must be small. They make up about 9% of the stars on the diagram.