The brightness of a star is measured from earth is called apparent magnitude.
A stars absolute brightness is that of a star placed at a standard distance of 10 parsecs from earth.
A color of a star reveals the surface temperature.
The size of a star influences its brightness by the surface area. The surface area allows more light and energy to be given off.
HR diagram is a 2 dimensional diagram of a scatter plot of stars showing the relationship between the stars’ absolute magnitudes or brightness versus their stellar classifications or temperatures.
Stars are categorised by top to bottom of order of decreasing magnitude( brightness) and right to left by increasing temperature.
Properties;
Supergiants-diameter of several hundred times that of a sun, brightness of nearly 1,000,000 times as great.
Giants-having a relatively large radius for its mass and temperature
Main sequence-source of their energy
Dwarfs-low brightness, mass on order of the sun, radius comparable to earth
Approx of dwarf star A= -3
Approx B=2
C=3
Brightness of 5..=supergiants
What determines the fate of a star? It’s mass; larger the mass the shorter it’s life cycle.
A nebula is a giant cloud of dust and gas in space.
Proto-stars are formed by gravity beginning to pull the gases together into a ball.
What happened within a protostar to create a star? Stars begin to form from the clouds of gas in space.
Blue stars are the hottest stars.
Our sun is medium sized star with a temperature around 6000 degrees Celsius.
Hope this helps.