PCS 181 Lecture Notes - Lecture 6: Hydrogen Atom, Radiography, Sn 1987A
23 May 2017
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H2 molecules dissociate: the contracting object is a protostar. The abundance of heavier elements are increasing: eventually stars will cease to form and stelliferous (era of stars) will end. Unit 5: measuring stellar properties: apparent magnitude (m, hipparchus of greece (2nd century b. c. ) divided the visible stars into. = 5. 14 (no units: because of smog and air pollution, the sun would be barely visible at. 10pc from us: luminosity, luminosity (l) is the total amount of energy emitted by the star each second, q: the surface of the sun is 5800k. Ro in m: if, l = 4 r2 t4, then, r = (l/4 t4)1/2. M=~2 (on the hr diagram: m = m + 5 - 5log(d) d = 10(m-m+5)/5. = 100. 38 pc = 2. 4pc = 7. 8 ly: q: spica is a main sequence star, spectral class b0, apparent magnitude 0. 91. How far is spica in pc: hr diagram m~ -3. 5 d = 10(m-m+5)/5.
