textbook chapters 24 - stars textbook chapter 25 - universe stellar evolution for...
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Textbook Chapters 24 - StarsTextbook Chapter 25 - Universe
Regents Earth Science with Ms. Connery
STAR LIGHT gives us characteristics of stars & galaxies
SPECTROSCOPY is the study of light.
Read to learn - textbook
pages 674-677
From VISIBLE LIGHT From SPECTRUM
• luminosity - brightness based on how much energy is being emitted from the star
• temperature - how fast the molecules are moving
• distance - how far away the star is
• size - how big the star is
• composition - what star is made of
• Doppler motion - if star is moving towards or away from observer
STARLIGHT
spectroscopy
nuclear fusion
hydrogen helium
self-illuminating
emit light (emission)
electromagnetic spectrum
EM wavelengths
star mass
luminosity
visible color & temperature
spectrum & composition
BIG BANG
Doppler effect
red shift (expanding universe)
blue shift (collapsing universe)
STELLAR EVOLUTION
protostar
main sequence star
giant star
supergiant star
dwarf star
nova
supernova
black hole
We see all these EM energy forms coming from stars. If we can “read” them we gain knowledge of things that are very
distant both in space and time!
http://www.pbslearningmedia.org/asset/phy03_int_chandra/
☼ Universe – everything that exists☼ Galaxy – contains 100 x 109 solar systems☼ Nebula – where stars form☼ Solar system – star + its orbiting planets☼ Star – energy emitting mass of incandescent gas
held together by gravity☼ Natural satellites in orbit around a central
“body”☼Planets (orbit stars like our sun)☼Moons (orbit planets)
☼ Human-made satellites
200 B stars
Our solar system is 2/3 out from center
Orion Nebula – star
forming region
How does
nuclear fusion in
the core of stars
emit light and
what does that
light tell us? (text pgs689-90)
Corona
STARS are
self-illuminating
and give off
their own light
as long as there’s
nuclear fusion in
the core!
STARS
HAVE
DIFFERENT
LAYERS
Energy production in stars by NUCLEAR FUSION
Hydrogen IS TURNED INTO Helium
fusion requires extremely high temperature (millions of degrees) and pressure
“fused” nuclei RELEASE ENERGY (just like nuclear fusion weapons)
Energy is released in all directions (sphere shape)
Our eyes can only see the visible light
How does a matrix
of star size, color,
temperature, and
luminosity show
us the life cycle of
stars?
Star Anatomy (text pg 684-686)
Hertzprung Russell Diagram (ESRT graph) of Star
Characteristics (text pg 704-706)
Stellar Evolution (text pg 707-714)
In order to see the
characteristics of stars and
how they group out, data for
hundreds of thousands of
stars were “graphed.”
You’ll just do a few to get the
idea (and appreciate the work
it takes to see these patterns!
MAIN SEQUENCE (young & stable)Temp rangeColor rangeLuminosity rangeSize range
WHITE DWARF (old age & dying)Temp rangeColor rangeLuminosity rangeSize range
GIANT (middle age and unstable)Temp rangeColor rangeLuminosity rangeSize range
SUPERGIANT (middle age & unstable)Temp rangeColor rangeLuminosity rangeSize range
Stars start as PROTOSTARS in the nebula.
A star is STABLE on the MAIN SEQUENCE as long as the OUTWARD FORCE (RADIATING ENERGY) = INWARD FORCE (GRAVITY)
When the star becomes UNSTABLE, and it “MOVES OFF” THE MAIN SEQUENCE, as it’s characteristics change.
It starts to DIE by expanding (GIANTS) and then collapsing (DWARFS and BLACK HOLES)
LARGER stars are less stable, have shorter life spans, and go out with a “bigger” show!
All stars start main sequence and “expand”
If low to mid-size star mass (like our sun)
expands to red giant
goes nova and blows off outer expansion zone and is left with core as a white dwarf
black dwarf when no energy left so no illumination!
All stars start main sequence and “expand”
If starts as ,
supergiant
supernova
neutron star (very dense)
All stars start main sequence and “expand”
If very high mass star (>10x sun)
supergiant
supernova
black hole (extremely high gravity field that attracts things to it)