ASTRON 100 Lecture Notes - Solar Mass, Absorption Spectroscopy, Stellar Classification
21 Jan 2014
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Document Summary
Luminosity- amount of power that a star radiates (energy per second = watts) The apparent brightness of a star depends on both distance and luminosity. Apparent brightness- amount of starlight that reaches earth (energy per second per. The relationship between apparent brightness and luminosity depends on distance. We can determine a star"s luminosity if we can measure its distance and apparent square meter) brightness. The amount of luminosity passing through each sphere is the same. Surface area of sphere= 4 pi (radius)^2. Divide luminosity by area to get brightness. Parallax us the apparent shift in position of a nearby object against a background of more. Apparent positions of nearby stars by about an arcsecond as earth orbits the sun. Most luminous stars : 10 ^6 lsun. M = apparent magnitude , m = absolute magnitude. Apparent brightness of star 1 / apparent brightness of star 2 = (100^ Luminosity of star 1 / luminosity of star 2 = (100^
