PCS 181 Lecture Notes - Lecture 9: Planetary Nebula, Minute And Second Of Arc, Proper Motion

• School: Ryerson University
• Department: Physics
• Course: PCS 181
• Professor: Margaret Buckby

Document Summary

Tangential velocity is the component of the star"s velocity perpendicular to our line of sight. Vt = 4. 74 x 103 u d. U is in arcsec per year ( /year). Space velocity (vs) is the actual velocity of the star in space. Question: a nearby white dwarf has a parallax angle of 0. 232 arcsec ( =0. 232 ). Its proper motion is 2. 95 arcsec/year (=2. 95 /year) and its radial velocity is 54 km/s. Vt = 4. 74 x 103 ud, we need d. D = 1 = 1 = 4. 31 pc. Vt = 4. 74 x 103 (2. 95) (4. 31) = 60. 3 x 103 m/s = 60. 3 km/s. Vs = 80. 9 km/s ~ 81 km/s. The manner of death is determined by the star"s mass. Death of lightweight stars: remember for the test we need 10 million k. These are normal stars 95% of stars are in this category. 1) core runs low on hydrogen fuel. Star"s leaves main sequence (=hydrogen fusion) phase.