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GEOL3045: Planetary Geology. Lysa Chizmadia The Sun & Ulysses. Introduction. Image from: http://seds.org/nineplanets/nineplanets/sol.html. Mass = 1.989 x 10 30 kg 99.8% of solar system Diameter = 1.39 x 10 6 km Temperature 5800 (sfc) - 1.56 x 10 7 K (core) Class G star (G2V)
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GEOL3045: Planetary Geology Lysa Chizmadia The Sun & Ulysses
Introduction Image from: http://seds.org/nineplanets/nineplanets/sol.html • Mass = 1.989 x 1030 kg • 99.8% of solar system • Diameter = 1.39 x 106 km • Temperature • 5800 (sfc) - 1.56 x 107 K (core) • Class G star (G2V) • Population I star • metallicity high • Galactic velocity • 2.17 x 105 m/s • Galactic period • 2.25-2.5 x 108 a Image from: asdictionary.blogspot.com
Spectroscopy • Pure white light yields continuous spectra, like a rainbow • Individual elements produce line spectra like fingerprints
Stellar Spectroscopy • Hot objects yields continuous spectra • Like a rainbow • Atoms emit light of specific wavelengths • Line spectrum • Individual to each atom (fingerprint) • Atoms in front of hot object, absorb light at their fingerprint wavelengths • Absorption spectra Images from: http://www.arm.ac.uk/~csj/pus/spectra/tot_l.html
Sun’s Spectra • Sun is relatively cool (T=5,500K) • For comparison, Vega (T=10,000K) Images from: http://www.arm.ac.uk/~csj/pus/spectra/tot_l.html
Sun Spots • Cooler parts of Sun’s surface • 3800 K vs. 5800 K • 22 year cycles • Change in magnetic poles • Differential rotation • Equator = 25.4 days • Poles = 36 d • Layers: Image from: http://en.wikipedia.org/wiki/Sun Image from: http://seds.org/nineplanets/nineplanets/sol.html Image from: nmp.nasa.gov/ st5/SCIENCE/sun.html
Aurora Images from: http://en.wikipedia.org/wiki/Aurora_(astronomy) • Borealis = north • Australis = south • Interaction of solar wind with Earth’s magnetic field • Particles have E from 1-100 keV • Collisions with oxygen • Green and red emissions • Collisions with nitrogen • Low level red and very high blue/violet Image from: http://en.wikipedia.org/wiki/Image:Aurora_australis_20050911.jpg
Ulysses Mission • Launched by NASA in 1990 • Gravity boosts by Jupiter in 1992 • Sling-shotted out of ecliptic • Perihelion = 5.2 AU • Aphelion = 1.5 AU Image from: http://ulysses.jpl.nasa.gov/
Ulysses (con’t) • New solar cycle starting • Will be able to study sun spot cycle • How does a change in magnetic field effect solar wind, galactic cosmic rays & us on Earth? • Mission highlights: • Observed 4 large coronal mass ejections merge into large interplanetary shock wave • Feb 2005 • Discovered e- jets from Jupiter • Feb 2006 • Near pass with comet C/2006 P1 McNaught • Feb 2007 Image from: http://ulysses.jpl.nasa.gov/
Summary • Sun is main sequence star • In mid-life • Population I star • High metallicity • Ulysses mission • Launched in 1990 • Should reveal how changes in solar magnetic field effect solar wind, background radiation & current technology