Fluxes and Magnitudes Flashcards
1
Q
What is
Luminosity
A
Power output of an object
2
Q
What is
Flux
(f)
A
- Power (Luminosity) per unit area
- How bright an object appears to an observer
3
Q
What is the equation for
Flux
(f)
A
f = L / (4πd^2)
L is luminosity, d is distance from observer to object
4
Q
What is
Apparent Magnitude
m
A
- How bright an object looks in the sky, using your eyes.
- Smaller magnitude, brighter object. ie 1>5
- Increase of 5 magnitudes corresponds to decrease of flux by factor of 100
5
Q
What is the equation for
Apparent magnitudes and fluxes
A
m2 - m1 = -2.5 log(f2/f1)
m = magnitude, f = flux
6
Q
What is
Absolute magnitude
M
A
The apparent magnitude of an object if it were 10pc away.
7
Q
What is the equation for
Apparent and Absolute magnitudes, distance
A
m - M = 5 log(d/10pc)
m = apparent magnitude, M = absolute magnitude, d = distance in parsecs
