Please enable JavaScript.
Coggle requires JavaScript to display documents.
Quantifying light - Coggle Diagram
Quantifying light
magnitude scale
a magnitude difference of 5 should be exactly equivalent to a brightness ratio of 100 to 1
Pogson equation
wavelength
visual magnitude
bolometric magnitude
absolute bolometric magnitude
absolute magnitude
the apparent magnitude a star would have if it were moved to a distance of 10 parsec
distance modulus
apparent distance modulus
extended astronomical objects
integrated magnitude
surface brightness: the magnitude corresponding to the average flux in one arcsec
Filter systems
UBV color system
Cousins RI system
UBVRI color system
UVBY color system
Stellar spectral types
early: absorption lines of hydrogen
A, B, C, D...
Henry Draper Catalog: temperature
OBAFGKM
the line of hydrogen became stronger from O to A, and weaker from A to M
the blue stars of O are hottest, the red stars of M are the least hot
modern: Ia>Ib>II>III>IV>V
Flux
monochromatic flux
units
W cm^(-2) s^(-1)
photons s^(-1) cm^(-2)
Blackbody radiation
Planck function
approximations
Rayleigh-Jeans approximation
Wien's Displacement Law
Wien approximation
magnitude zero points
Polaris---Vega, Sirius---synthetic color
color index