Transcript 2009_01_28-LP06-Star-Life

Astronomy 100
Are All Stars the Same?
• Answer Now: Why does the Sun shine? Are all
stars the same as our Sun? (How or how not?)
• Goal:
– Be able to tell me how stars are born
– Know what stars are made of
– Know how stars shine
– (if we have time) Know how stars die
• Vocabulary: Planck curve, luminosity, H-R Diagram,
absolute magnitude, apparent magnitude, fusion, H,
He, CNO Cycle, protostar, nebula, protostar,
hydrostatic equilibrium, interstellar medium,
compression wave,
http://www4.nau.edu/meteorite/Meteorite/Images/PlanckCurve.jpg
Planck Curve - Temperature DIRECTLY related to peak wavelength.
• Luminosity
– Apparent magnitude
– Absolute magnitude
– Luminosity is the total brightness
• Temperature or Type
– Can tell temp from color
– Can tell type from spectrum, temp or color
• Types: O, B, A, F, G, K, M
http://www.eso.org/gallery/d/4380-2/phot-28c-07.jpg
http://raviramanathan.blogspot.com/2007/05/life-cycle-ofstar.html
It all starts with gas
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Interstellar medium
Gas cloud (nebula)
Compression wave
Pockets of compacted gas
Gravity further squeezes gas
PROTOSTAR!
Squished enough (enough energy) fusion
begins
• STAR!
E=mc2
H+H+H+H+H+H =
He + H + H+ energy
Hydrostatic Equilibrium
Energy
from fusion
• Compression Wave:
http://video.google.com/videoplay?docid=6732533372822687572&ei=c_iASe30OZ64qA
PS-MSVDg&q=slinky+compression&hl=en
http://people.maths.ox.ac.uk/schmitz/Files/starlife.jpg
And in the end…
• < 4 Solar Mass – when finished fusing H,
begins to fuse He
• Ffffffft (planetary nebula)
• White dwarf/black dwarf
• > 4 Solar Mass – when finished fusing H,
begins to fuse He – when finished fusing He,
begins to fuse C, N, O (shells)
• Kerblewie! (supernova)
• Black hole/neutron star
• Review – define 3 of the terms at the
beginning of this lecture.
• Quiz Review
“High Mass Stars”
My candle burns at both ends;
It will not last the night;
But ah, my foes, and oh, my friends-It gives a lovely light.
Emily Dickinson
• Brownian Motion:
http://www.youtube.com/watch?v=43BKoqQxsM