Consider the Hertzsprung Russell diagram seen here. We can use this diagram to classify stars and determine their characteristics. The color of a star is determined by its temperature: the hottest stars are blue and the coolest are red. The Sun has a surface
temperature of 5,500°C and it appears yellow. The diagram also indicates that temperature coincides with luminosity: the hotter the
star, the higher the luminosity. You can also tell the size of each star from the graph as the larger the radius, the higher the
temperature and luminosity. Regardless of a star's position in the diagram, the energy that results in high temperatures and the stars
luminosity is generated by what process?
W
A)
nuclear fusion
B)
nuclear fission
gravitational forces of swirling gases
D)
friction generated by gravitational force