AS_module6A_syllabus

15.3 Classification of stars
15.3.1 Classification by luminosity	Relation between brightness and apparent magnitude
15.3.2 Apparent magnitude, m	Relation between intensity and apparent magnitude Measurement of m from photographic plates and distinction between photographic and visual magnitude not required
15.3.3 Absolute magnitude, M Powerpoint demo: Astronomical distance m, M and the parsec	Parsec and light year Definition of M, relation to m m – M = 5 log d 10
15.3.4 Classification by temperature, black body radiation powerpoint	Stefan’s law and Wien’s displacement law General shape of black body curves, experimental verification is not required Use of Wien’s displacement law to estimate black-body temperature of sources λ_maxT = constant = 0.0029 mK Inverse square law, assumptions in its application Use of Stefan’s law to estimate area needed for sources to have same power output as the sun P = σ AT⁴ Assumption that a star is a black body Problem of detector response as a function of wavelength and atmospheric effects
15.3.5 Principles of the use of stellar spectral classes	Description of the main classes, O B A F G K M Temperature required: need for excitation Helium absorption (O): need for higher temperature Hydrogen Balmer absorption lines (B, A): need for atoms in n=2 state Metals absorption (F, G): occurs at lower temperature Molecular bands (K, M): occur at lowest temperature
15.3.6 The Hertzsprung- Russell diagram power point link to stellar evidence multi-choice on the lifecycle of stars	General shape: main sequence, dwarfs and giants Stellar evolution: path of a star similar to our Sun on the Hertzsprung- Russell diagram from formation to white dwarf
15.3.7 Supernovae, neutron stars and black holes PowerPoint - right mouse click and choose "save as"	General properties Calculation of the radius of the event horizon for a black hole Schwarzchild radius (R_s) R_s» 2GM c²
15.4 Cosmology
15.4.1 Doppler effect PowerPoint - right mouse click and choose "save as"	Df = v and Dλ = -v f c λ c for v « c applied to optical and radio frequencies Calculations on binary stars viewed in the plane of orbit
15.4.2 Hubble’s law example doppler shift question	Red shift v = Hd Simple interpretation as expansion of universe; estimation of age of universe, assuming H is constant Qualitative treatment of Big Bang theory
15.4.3 Quasars	Quasars as the most distant measurable objects Discovery as bright radio sources Controversy concerning distance and power – use of inverse square law Quasars show large optical red shifts; estimation of distance
Revision Resources
Glossary - unfinished - based on last year's syllabus
Another Glossary
PH04 past module exam questions March2000, Feb96 & March97