classification of stars by temperature Flashcards
what is luminosity measured in
watts
what is luminosity
the total power output of a star
what is Stefan’s law
L = σAT^4
L = luminosity [W] A = surface area [m^2] T = surface temp [K] σ = stefan-Boltzmann constant - 5.67x10^-8 [Wm^-2K^-4]
how is luminosity defined
by Stefan’s law
What is Wien’s law
λmaxT = constant λmax = peak wavelength [m] T = black body surface temp [K] constant = 2.9x10^-3[mK]
list the e.m spectrum from largest λ to smallest λ
Radio Microwave Infra-Red Visible Ultra violet X-ray Gamma
acronym for em spectrum
Rap Music Is Very Underground Xclaimed Ghilardi
What is a black body
an object that emits across the whole em spectrum
what kind of λ will a cool black body produce
longer λ
what kind of λ will hot black body produce
shorter λ
Draw a black body radiation curve
under I group of flashcards
why do stars produce absorption spectra
because the ‘cold’ outer layers of the star absorb photons produced in the hot core - atoms in the colder outer layers are excited by absorbing photons from the hot core. electrons rise to higher energy levels removing specific λ of light from the stars spectra
how could λmax be measured
using a spectrometer which uses a diffraction grating to separate the light into its component λ. the resulting spectra will reveal the λ associated with λmax.
