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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)
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 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
Image from: http://en.wikipedia.org/wiki/Sun
 Change in magnetic poles
 Differential rotation
 Equator = 25.4 days
 Poles = 36 d
 Layers:
Image from:
http://seds.org/nineplanets
/nineplanets/sol.html
Image from: nmp.nasa.gov/ st5/SCIENCE/sun.html
Aurora
 Borealis = north
 Australis = south Images from: http://en.wikipedia.org/wiki/Aurora_(astronomy)
 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 inImage
1992
from: http://ulysses.jpl.nasa.gov/
 Sling-shotted out of ecliptic
 Perihelion = 5.2 AU
 Aphelion = 1.5 AU
Ulysses (con’t)
 New solar cycle starting
 Will be able to study sun spot cycle
 How does a change in magneticImage from: http://ulysses.jpl.nasa.gov/
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
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