Astronomy 1021 Lecture Notes - Lecture 15: Apparent Magnitude, Parsec, Exoplanet
4 Oct 2018
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They have just one hour to learn all about life on earth. Cant see progression of one individual but will get snapshots of people of all ages. We. ve been doing modern science for even less time. Stellar life times can be up to billions of years. Betelgeuse and procyon appear the same brightness in the sky. Betelgeuse is actually 15 00 times brighter than procyon. Betelgeuse is 600 light years away: procyon is 11. 5 light years away. How bright a star appears in our sky. Amount of power an object radiates (energy per second = watts) Amount of light that reaches the measuring position (energy per second per m^2) Same amount of light passes through each sphere. Same amount of light that passes through one square on 1 au sphere must also pass through. Apparent brightness = luminosity/are of sphere or f = l/(4)(pie)^2. Brighter star could have a higher luminosity or be closer to us.
