Lecture 5
measure properties of astronomical objects
astronomy discoveries' sequence: observation to data to physics
properties of astronomical objects
positon motion
mass
size & morphology
luminosity
temperature
age
environment
composition
how those properties vary with time
radial velocity + tangential velocity = true velocity; proper motion: angle
calculate radial velocity from doppler shift
𝑀= 𝑎^3/𝑃^2
star formation rate
distance
measuring
from angular to actual length via velocities
Brightness = Luminosity / 4Pi distance*2
standard candles
variables / supernova / spectroscopic parallax
hubble constant v = H0r
the distance ladder
solar system / nearby stars / milky way / nearby galaxies / galaxy clusters
Quantify measurements
SNR
signal vs noise makes a detection
long sxposure to boost SNR
Noise = Signal*1/2
long exposures
𝑆/𝑁∝√(𝑡_𝑒𝑥𝑝 )