AST 10G Lecture Notes - Lecture 6: Radial Velocity, Double Star, Hipparcos
Document Summary
Chapter 7 class notes 10/27/16: angle goes to distance, use whole earth"s surface as a baseline to determine space , to make measurement (star) have to be presents without the atmosphere blurring. Parallax & distance: p=parallax angle in arcseconds, d=distance in parsecs, d=1/p. Alpha centauri with a measured parallax of~. 75 =3/4 : therefore, distance is about 4/3 of a parsec, or ~1. 3 pc. This is 1. 3 pc x3. 26ly/pc=4. 2ly: alpha centauri double star, proxima centauri (example, 3pc=10ly, alpha centauri ~1pc. Stellar parallax: can measure parallax angles small as . 03 (arcsecond) from ground distance out to. Stellar motion: combining distance and proper motion=transverse, from the doppler shift of a star"s spectrum, can measure its radial velocity, combining the transvers (or proper motion) and radial velocity we can get the true space. Temperatures of stars: measure temp, when figure out spectrum , wien"s law t=2. 9 x 10^7/peak of wavelength.
