PCS 181 Lecture Notes - Radial Velocity, Parsec, Vir Chakra
13 Apr 2013
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The spectral line is = 656. 2850nm in the lab (red line) The same line (in the spectrum of regulus is = 656. 2927nm) The regulus is longer than in the lab and is red shifted (moving away) P this ha/ has a longer wave length in the spectrum (red shifted) and is moving away from us. Vr = c*( / lab) = (3*10^8m/s)*(656. 2927nm 656. 2850nm/656. 2858nm) Using the doppler effect how can you tell that the sun rotates? (it rotates every 30 days) Cover up half of the star + check spectrum-moving up to you. Cover other half of the star + check spectrum moving away. **moving toward and away at the same time = rotating. Light year = 1ly: the distance travelled by light in a year. Parsec = 1pc: 1pc = 3. 26ly (1 mega parsec = 1000000ly) Astronomical unit = 1au: average distance between the sun and the earth.
