ISP Chapter 12 - Chapter 12: plus review for exam ? Where...

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Chapter 12: plus review for exam ? Where do the elements heavier than hydrogen and helium come from? -fusion reactions in stars and supernovae ? What are the most important properties of a star? -mass and age A star’s mass and age determine its other properties ? What do we mean by stars in gravitational equilibrium? -outward pressure from gas balances inward force of gravity ?what conditions are required for fusion reactions to happen? -high temperatures and high pressure ? What is the Sun’s source of energy? -nuclear fusion ? Where does fusion happen in the Sun? -only in the core HOW DO STARS FORM? Stars from in cold clouds where gravity can overcome thermal pressure Clouds continue to contract because they radiate away energy in the form of infrared light ? Gravity initiates star formation because it causes gas clouds to contract. Why does this contraction eventually stop in a star? -fusion begins supplying energy in the core STAR BIRTH 1. Gravity causes gas cloud to shrink and fragment 2. Core of shrinking cloud heats up 3. When core gets hot enough, fusion begins and stops the shrinking 4. New star achieves long lasting state of balance HOW MASSIVE ARE NEWBORN STARS? A single star forming cloud can give birth to an entire star cluster Very massive stars are rare Low-mass stars are common Lower limit at about .08 Msun ? Why don’t gas clouds with less than .08 Msun of matter become stars? -Something stops contraction before fusion starts ? how does gas pressure change with increasing temperature? -increasing pressure
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Degeneracy pressure : arises because laws of quantum mechanics prevent particles like electrons from occupying the same state in the same small region of space Stops the contraction of a
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ISP Chapter 12 - Chapter 12: plus review for exam ? Where...

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