Chapter 11-12 (The Stars) - The Stars The Properties of...

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The Stars
The Properties of StarsLuminosity- Another word for BrightnessTemperatureMass
BrightnessApparent brightnessAbsolute brightness – LuminosityInverse square law
Stellar MassTo directly determine mass, we need anorbiting object!Binary Star SystemsVisual BinaryEclipsing BinarySpectroscopic Binary
TemperatureColor – continuous spectrum – where is thepeak of the emitted radiation?Spectral lines – stars of differenttemperatures contain different elements,molecules, etc.
TemperatureWien’s Law:The hotter the object, the bluer the radiation itemits, and the more total energy is emitted.
TemperatureThe level of heat determines what sorts elements will be prominentin the star’s spectrumFor example only the hottest stars can ionize heliumOnly the coolest stars can have molecules
Spectral Type Classification SystemOBAFGKMOhBeAFineGirl/Guy,KissMe!50,000 K3,000 KTemperature(L)
Stellar EvolutionStars are like people in that they are born, grow up,mature, and die.Astar’smassdetermines what life path it will take.We will divide all stars into three groups:Low Mass(0.08 Mh< M < 2 Mh)Intermediate Mass (2 Mh< M < 8 Mh)High Mass (M > 8 Mh)
Stellar EvolutionThe life of any star can be described as a battlebetween two forces:Gravityvs.PressureGravity always wants to collapse the star.Pressure holds up the star.the type of star is defined by what provides thepressure
The Birth of StarsStars are born deep inmolecular clouds.cold (10 – 30 K) dense nebulaeso cold that H2can existA cold cloud can fragmentgravity overcomes thermalpressure in dense regionsthese regions (cores) becomemore dense and compactdark molecular cloud inScorpius

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Term
Spring
Professor
Britt
Tags
Supernova, White dwarf, main sequence

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