Lecture 2 Flashcards
(17 cards)
what are 3 types of measurements of astronomical data?
images
time series
spectra
what does astronomical data use to measure physical properties?
indirect proxy measurements
describe time series. What does it measure?
based on variations of brightnesses of celestial signals or changes in location on sky
measures motions, rotation, pulsations
what is a cepheid star?
star with pulsating optical light intensity
ie. stellar pulsation
what are radio pulsars? how do they compare to cepheid stars?
they have pulses that correspond to rotation of a neutron star
cepheids have fluctuations over days
radio pulsars have fluctations over seconds
describe spectra data. what does it determine?
it shows the “colors” of objects or E distribution of light
determines temp, composition, evolutionary state, motion toward/away from us
what is astronomical data based on?
collection of light or photons
isaac newton showed that white light is a ____ of colors
spectrum
what is the term to describe how light is a wave and particle?
dual nature
wavelength of red light?
wavelength of blue light?
660 nm
450nm
unit of frequency?
1/s or Hz
define light year
distance light travels in a year
define 1 astronomical unit
1 earth-sun distance
electrons travel within ____
orbitals of diff E
what happens when an atom emits a light wave?
electron jumps to a lower level
what happens when an atom absorbs a light wave?
electron jumps to a higher level
shapes of electron orbitals correspond to ______
different energies
