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The Solar System
Steinn Sigurðsson
Astro 420-1
The ‘hood
log(scale)
Content
Mercury: 0.055, 0.4 AU, 0.205
Venus:
0.815, 0.7 AU, 0.006
Earth:
1.00, 1.0 AU, 0.017
Mars:
0.107, 1.5 AU, 0.093
Jupiter:
318, 5.2 AU, 0.049
Saturn:
95, 9.5 AU, 0.056
Uranus:
14, 19.6 AU, 0.044
Neptune: 17, 30 AU, 0.011
Inclination, Radius, Density, Obliquity
Mercury: 7.0, 0.38, 5.4, 0
Venus: 3.4, 0.95, 5.2, 177.3
Earth: 0, 1.0, 5.5, 23.5
Mars: 1.8, 0.53, 3.9, 25.2
Jupiter: 1.3, 11.2 (10.5), 1.3, 3.3
Saturn: 2.5, 9.4 (8.5), 0.69, 26.7
Uranus: 0.77, 4.0, 1.3, 98
Neptune: 1.7, 3.9, 1.64, 28.3
Solar System
Jupiter - 0.1% solar mass. ~ 10 Earth mass
core of rock/iron, rest H/He - sedimenting
Saturn - failed Jupiter
Neptune/Uranus - ice sub-giants
terrestrials: Earth, Venus, Mars, Mercury
asteroids: sub-planetary mass types; processing and breakup
comets/KBO - trillions, large, scattered - icy
Planet X?
Batygin & Brown - sub-Neptune at few hundred AU
hinted at by clustering of Sedna like KBO perihelia
https://solarsystem.nasa.gov/galleries/video/planet-nine-animation
What is a Planet?
The International Astronomical Union
defined a planet as an object that:
orbits the sun
has sufficient mass to be round, or nearly round
is not a satellite (moon) of another object
has removed debris and small objects from the
area around its orbit
WHAT? https://solarsystem.nasa.gov/docs/video/
WhatIsAPlanet1.mov
Inner System
Summary:
Solar system extensive, with Oort cloud of comets going part way to nearest stars
Planets dominated by Jupiter. Three distinct categories(?): Jovian, Neptunian and Terrestrial. Jovian - ~ 10 earth mass metal core, H/He bulk atmosphere
Neptunian - ~ 10 earth mass core, low mass atmosphere, some H/He
Terrestrial - ~ 1 earth mass core, negligible atmosphere
is there Super-Earth category - ~ 10 earth mass core, negligible atmosphere
is there a No-Core Jovian type planet category?
Canonical formation scenario.
Moons
Outer System