physics 681: solar physics and instrumentation – lecture 2
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Physics 681: Solar Physics and Instrumentation – Lecture 2. Carsten Denker NJIT Physics Department Center for Solar–Terrestrial Research. Virial Theorem. Kepler’s 3 rd Law. Kepler’s 3 rd Law (cont.). - PowerPoint PPT PresentationTRANSCRIPT
Physics 681: Solar Physics and Instrumentation –
Lecture 2
Carsten Denker
NJIT Physics DepartmentCenter for Solar–Terrestrial
Research
September 6, 2005 Center for Solar-Terrestrial Research
Kepler’s 3rd Law(1 ) (perihelion)
(1 ) (aphelion)p
p p a aa
r a ev r L rv r v r v
r a e
2 21 1 1 and
1 2 (1 ) 2 (1 )p
p aa
v e M Mv G v G
v e a e a e
2 21 1 and
1 1p a
GM e GM ev v
a e a e
2(1 )p pL r v GMa e
2 1 21 1
2 2 2 2pp
mmM ME v G G G U
r a a
Virial Theorem
September 6, 2005 Center for Solar-Terrestrial Research
Kepler’s 3rd Law (cont.)21
2 2
M ME G v G
a r
21 2
2 1( )v G m m
r a
0 0 0
1 1 1
2 2 2
P P PdA L L LA dt dt dt P
dt
2 2 2 2 2 2 2 2 2 2
2 32 2 2
2 4 4 4
1
A a b a bP a
L L GMGMa e
Virial Theorem: For gravitationally bound systems in equilibrium, it can be shown that the total energy is always one-half of the time averaged potential energy.
September 6, 2005 Center for Solar-Terrestrial Research
Hertzsprung-Russell Diagram
http://www.physics.sjsu.edu/tomley/Planck.html
September 6, 2005 Center for Solar-Terrestrial Research
Sun – OverviewMass (kg)
1.99e+30
Mass (Earth = 1) 332,830
Equatorial radius (km) 695,000
Equatorial radius (Earth = 1) 108.97
Mean density (gm/cm3) 1.410
Rotational period (days) 25-36
Escape velocity (km/sec) 618.02
Luminosity (ergs/sec)3.827e3
3Magnitude -26.8
Mean surface temperature 6,000°C
Age (billion years) 4.5
Principal chemistry
Hydrogen Helium Oxygen Carbon Nitrogen Neon Iron Silicon Magnesium All others
92.1%7.8%
0.061%0.030%
0.0084%0.0076%0.0037%0.0031%0.0024%0.0030%
September 6, 2005 Center for Solar-Terrestrial Research
Parameters Astronomical unit [AU]: A = 149,597,870 ± 2 km (perihelion
in January: 1.471 × 1011 m; aphelion in July: 1.521 × 1011 m) Travel time: τA = 499.004782 ± 0.000006 s Velocity of light: c = 299,792,458 m s–1
Constant of gravitation: (6.67259 ± 0.00085) × 10–11 m3 kg–
1 s–2
Mass of the Sun: m = (1.9889 ± 0.0003) × 1030 kg Radius: r = (6.960 ± 0.001) × 108 m Mean density: ρ = 1.408 g cm–3
Gravitational acceleration: g = 274 m s–2
Solar constant: S = 1367 ± 3 W m–2
Luminosity: L = (3.844 ± 0.010) × 1026 W Magnitude: M = 4.74 (absolute) and m = –26.74 (apparent) Effective temperature: Teff = 5778 ± 3 K
September 6, 2005 Center for Solar-Terrestrial Research
Electromagnetic SpectrumGroup Problem:
List a few solar phenomena that you know!
Where in the solar spectrum would you try to observe these solar phenomena?
September 6, 2005 Center for Solar-Terrestrial Research
Solar Spectrum
http://www.spacewx.com/solar_spectrum.html
http://www.noao.edu/image_gallery/html/im0600.html
September 6, 2005 Center for Solar-Terrestrial Research
Planck Function (
http://scienceworld.wolfram.com/physics/PlanckLaw.html)
Wavelength form:
Frequency form:
Wien displacement law:
Rayleigh-Jeans law:
Wien law:
Stefan-Boltzman law:
2 5
/
2 /( )
1hc kT
hcB T
e
3 2
/
2 /( )
1h kT
h cB T
e
3
max
2.898 10 K m
4.965 T
hc
kT
2 2( ) 2 / for ( )B T kT c h kT
3 2 /( ) (2 / ) for ( )h kTB T h c e h kT
4 5 4 2 3 with 2 /(15 )F T k c h