太阳系的演化.ppt

Lecture 1 太阳系的演化
太阳系一些基本观测事实
太阳系的动力学过程
太阳系形成模型
进一步的检验和太阳系探测计划
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太阳系天体
行星 Planets : the big bodies orbiting the Sun
T<20 y
T>20 y
a>10000 AU
a<10000 AU
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Main Asteroid belt
2-
Kuiper belt
30-50AU
Oort cloud
3000-100,000AU
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自转方向多数和轨道一致; 类木行星自转快
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太阳系天体的轨道特征
除Pluto之外基本在一平面
轨道基本上是圆的，除了水星和Pluto之外
轨道方向和太阳自转方向一致
行星的自转方向和轨道基本同向
小天体主要分布在主小行星带(火星和木星之间)和Kuiper带(Neptune之外)
短周期彗星远日点和Kuiper带相接
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行星分类
by composition:
Terrestrial(类地) or rocky planets: Mercury, Venus, Earth, and Mars:
Composition: rock and metal
high densities, slow rotation, solid surfaces, no rings and few satellites.
Jovian(类木) or gas planets: Jupiter, Saturn, Uranus, and Neptune:
Composition: primarily of hydrogen and helium
generally low densities, rapid rotation, deep atmospheres, rings and lots of satellites.
by size:
small planets: Mercury, Venus, Earth, Mars.
diameters less than 13000 km.
giant planets: Jupiter, Saturn, Uranus and Neptune.
diameters greater than 48000 km.
The giant planets are sometimes also referred to as gas giants.
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行星分类
by position relative to the Sun:
inner planets: Mercury, Venus, Earth and Mars.
outer planets: Jupiter, Saturn, Uranus, Neptune.
The asteroid belt between Mars and Jupiter forms the boundary between the inner solar system and the outer solar system.
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可居住区域(Habitable zone)
液态水： 273K<T<373K
温度估计: 行星黑体近似
实际情况比这复杂：行星不完全吸收(反照率), 辐射也非黑体，行星转动慢等， 实际温度比上面高
此外跟轨道偏心率也有关
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Gas giant planets, Jovian
Small rocky planets
类地和类木行星分界与位置上分界一致
Terrestrial planets
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Mercury
Earth
Internal structure of Terrestrial planets
Fraction of core increases with mass (except Mercury)
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Jupiter
Internal structure of gas giants
Core (rocky planet)
metallic H/He: due to high pressure
liquid molecule:
Atmosphere:
clouds of methane and ammonia
1000 km
mainly, H2, He
r=12,000 km
50,000 km
Fortney 2007
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Planet
mass
Equatorial Radius
Average density
Rotation Period
Oblateness
Albedo
Mercury