AST201H1 Lecture Notes - Lecture 3: Parsec, Main Sequence, More Stars
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Luminosity: the amount of energy an object emits per unit time. It is the total amount of power (energy per second) the star radiates/emits into space. 100-watts unit of power, how much a light bulb will heat up per second/ amount of energy per second. It puts out the same amount of light (luminosity) but its brightness depends on how far away you are from it. Luminosity of the sun 4x 1026 w. one solar luminosity or 1l . Luminosity tells how bright something is naturally (by looking at it) Main property that will determine a star"s luminosity is its mass more mass, more luminous. It will determine the rate of nuclear fusion reaction and how much energy is released. To measure a star"s luminosity we need to know its apparent brightness (how bright it appears to be) and distance. Luminosity/ solar luminosity does not change no matter how many light years it is seen from.