A new spectacle in the sky

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A new spectacle in the skyComet Holmes
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What Comet Holmes looks likein a small telescope
it shows a disk
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Where is Comet Holmes in space?

• Perihelion2.166 au
• Aphelion5.200 au
• Period7.068 yr

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Comet Holmes location in the solar system

• Question for audience whats wrong with this
  picture? Hint get your SC1 charts

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Stay tuned

• Watch the skies! Watch the skies!

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Further (better?) evidence for protoplanetary
disks around stars Fomalhaut
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An artists conception of the Fomalhaut system
now..like the Solar System 4 Gyr ago
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My summary of stellar evolution

• Evolved stars have fused (used up) the hydrogen
  in their cores
• The centers of these stars consist of burned out,
  incredibly dense cores, surrounded by shells
  where nuclear reactions are occurring
• The outer parts of the stars get big, red, and
  bloated
• Evolved stars move around in the upper part of
  the HR diagram
• In an evolved star, its external appearance gives
  little indication of its internal structure
• Mass is destiny

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Betelgeuse (Alpha Orionis), poster child of an
evolved star
A Hubble telescope Picture of Betelgeuse
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Betelgeuse is a red supergiant
Deep in its interior is a Massive, incredibly
compact Stellar remnant
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When you look at a Main Sequence star, the
appearance of it exterior tells you what it is
like inside
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In an evolved star, the appearance of the surface
is not a good indicator of its deep interior
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As cores contract, the density goes to
astronomical levels, matter acts in funny ways

• Gas in this room, the perfect gas law PVnRT.
  Pressure depends on both density and temperature
• Extremely dense, degenerate gas PVKn.
  Pressure depends only on density
• Demo

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Old evolved stars throw off their outer layers,
revealing the weird cores
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These compact cores exist.the white dwarf stars
Nearby examples Sirius B and Procyon B
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The physics of white dwarf stars

• What holds them up?
• What determines their properties?