PCS 181 Study Guide - Midterm Guide: Triple-Alpha Process, Giant Star, Baryon

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

Document Summary

H2 molecular clouds h1 regions and 21 cm wavelength star birth scenario size of cloud >~ 10 ly main sequence stage hydrogen fusion reactions mass converted to energy. 90-95% of stars are main sequence lifetime of sun red giant stage helium fusion reactions shell fusion of massive stars distance via parallax method apparent magnitude (m) absolute magnitude (m) luminosity radius. Harvard spectral classification system spectral type spectroscopic parallax period-luminosity carve for cepheid variable stars radial velocity proper motion tangenital velocity space velocity. Unit 4- birth of stars feb 23 rd. Interstellar matter- the dust and gas that occupy space between stars. Stars form in this dust/gas in clouds (neblue) in space. Dust- ~1% of total visible mass in space, out of 4% known baryonic matter. Mixture of : tiny grains of dirty ice, carbon, silicate particles, and comples particles. Interstellar reddening - light from star passes through the dust.