The Properties of Stars

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The Properties of Stars
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1. Flux density F is given in terms of luminosity
L, distance d,
Apparent magnitude m is given as a function of
flux F
3. So apparent mag. M and absolute mag. as
function of L, d
4. So app. magnitude m is given as a function of
M, d is
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• Is Sirius brighter or fainter than Spica
• as observed from Earth apparent magnitude
• Intrinsically luminosity?

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Sun
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U
B
V
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Little Dipper (Ursa Minor) Guide to naked-eye
magnitudes
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Use UVRI filters to determine apparent magnitude
at each color
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Relationship between luminosity L, radius R and
surface temperature T for a spherical black-body
(e.g. star)
Luminosity (normalized by Suns luminosity) as a
function of the bolometric luminosity Mbol and
the Suns bolometric luminosity (4.85).