11B.1 StarShine Flashcards
what is a red giant
a large star which is cooler than our sun, eq 3000k
what is a white dwarf
a small, hot star, perhaps 10 000k
what is a blue super giant
a very large, very hot star, perhaps 25 000k
what can the electromagnetic emission from the stars tell us
their temp, chemical composition, speed of movement, age, size and much more
what is a black body radiator
a theoretical object, that completely absorbs all radiation that lands on it
how does a black body radiator work
it is imagined as a cavity with a tiny hole, as the radiation lies on the hole it will go into a box (or a cavity) and bounce around with no chance of escaping out of the hole before it is absorbed inside the box
a black body is considered a
prefect emitter of Em
all objects emit
Em radiation
what is luminosity
the rate at which energy of all types is radiated by an object in all directions
what is luminosity effected by
size and temp of the object
what is the Stefan-Boltzmann law
the power output of a black body is proportional to its surface area and the fourth power of its temp in kelvin L= σAT^4
what is a star considered when calculating luminosity
a black body radiator which is a ‘perfect emitter’
a prefect black body radiator will emit
energy across the entire electromagnetic spectrum, giving distribution graphs which makes it a perfect emitter
in the Stefan-Boltzmann graph what happens to a star when its hotter
it releases more energy with the peak being more predominant but the wavelength would be shorter (page 180
what is Wien’s law
the relationship between the peak output wavelength and the temp given by a black body radiator (which we consider as a star) given by the equation: λ max x T = 2.898 X 10^-3 (2.898 X 10^-3 THIS IS WEINS CONSTANT)
