Chapters 11-12 The Life and Death of Stars

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Chapters 11-12 The Life and Death of Stars
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Baby in Womb

Stars form out of enormous volumes of dust and
gas_________________________
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__________________ trigger the birth of stars.
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Baby

• Eventually dense cores contract under gravity to
  form
• _____________
• particles collide frequently with each other and
  heat the gas

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Teen-ager

• Internal pressure slows down the collapse
• ______________
• Disk of rotating nebula begins to form

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Adult

• As the temperature in the interior rises,
  nuclear reactions produce outward force and
  balances the inward force of gravity ?
  __________________________ star becomes stable
  and stops collapsing
• ___________________

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Energy Sources in Stars

• ________ nuclei fuse to become ___________
  nucleus
• Since the mass of ____________nuclei is greater
  than the mass of _________ nucleus, the leftover
  mass (0.7) is converted to energy by Einsteins
  equation __________

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Adult

• _______________________ stars that are
  maintaining hydrostatic equilibrium by fusing
  hydrogen into helium in the core

Stars spend most of their lives in the ________
stage just like humans
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The end states of stars depends upon its
_________!
The more _________ a star, the _________ it
consumes its fuel, the _________ its lifetime
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A B C
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Evolution of Low Mass Stars including our Sun M
lt 10 Solar Masses

• When star runs out of hydrogen in core,
• gravity contracts star again
• heats up hydrogen in outer layers
• outer layers expand and cool down
• star becomes a ________________
• temperature becomes high enough in core for
  _________ to convert to _______ atoms

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Old Age
stars like our Sun will become __________ in
their old age
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Red Giant
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Elderly, dying star
The burned-out _________of a low-mass star
becomes a ________________
The core of the white dwarf star is now all
___________ _____________
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Elderly, dying star
_______________ of a dying star like our sun will
slowly drift away to become a ________________
Ring Nebula
Dumbbell Nebula
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End State of a Low-Mass Star
The _______ of our Sun will be a ___________ and
the ____________ will be a ______________
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Red Giant
Collapsing Proto-star
Main Sequence Star
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Yeah, but what about the really BIG stars?
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Evolution of High Mass Stars M gt 10 Solar Masses

• Have ____________ lifetimes than low mass stars
• Live on Main Sequence for only ___________ years
  (1000 times faster than Sun)
• After hydrogen depletion in the core, the outer
  layers expand and star becomes __________________
• Becomes ultra-bright and large!

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Old Age
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Elderly, dying star
Outer Layers
High-mass stars die violently by blowing
themselves apart in __________ explosions
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Elderly, dying star
Core
High mass stars becomes so dense that
________ and ________combine to become _________
and star becomes ___________ that is
composed of ______________
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End State of ____________ Star
Core
Outer Layers
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We are the stuff that stars are made of!

• Supernova spread _____________
• into space which are later recycled
• into new born stars
• The Sun and our solar system were formed from
  debris of many previous generations of stars
• These heavy elements are necessary for life

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Pulsars

• first detected in 1967 by Cambridge University
  graduate student Jocelyn Bell
• Radio source with an regular on-off-on cycle of
  exactly 1.3373011 seconds
• Some scientists speculated that this was evidence
  of an alien civilizations communication system
  and dubbed the source LGM
• Little Green Men
• Today, we know pulsars are rapidly spinning
  neutron stars.

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Pulsars
THE LIGHT HOUSE MODELA rotating magnetic field
explains the pulses from a neutron star
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Red Super Giant
Collapsing Proto-star
Main Sequence Star
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Temperature-Luminosity Diagrams
Hertzsprung Russell Diagram