ASTR 1102 : Frank Exam 2 Lecture Notes And Summaries
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1. 3. 2. d (in parsecs) = 1/p (in arcseconds) 1. 3. 3. d (in light-years) = 3. 26 x 1/p (in arcseconds: lecture 9. Two stars of magnitude m1 and m2 have brightness ratio b1/b2 = (2. 512)^(m2-m1) Star of magnitude 7 is brighter than magnitude 9 star by 6. 31 times. Light is both in particle form and wave form: lecture 10. Parsec is the distance corresponding to a parallax of one arc second. 1 arc second = 1 degree/3,600: lecture 11. Temperature and luminosity on an object of fixed size are directly proportionate. Hotter objects emit more light per unit of area at all frequencies. Hotter objects emit photons with a higher average energy. About half of all stars are in binary systems. If we measure a star"s apparent brightness and distance, we can compute its luminosity with the inverse square law for light. Parallax tells us distance to the nearest stars. A star"s color and spectral type both reflect its temperature: lecture 14.
