ASTR 2310: Chapter 12

The Solar System in Perspective Comparative Planetology (“Lessons”)

Origin of the Solar System

Exoplanets

– Detection

– Properties

See Exoplanet Resources posted at http://www.mikebrotherton.com/2010/04/27/online-resources-for-exoplanets/

ASTR 2310: Chapter 12

Comparative Planetology Lesson 1: Surfaces of planets are shaped by competing

internal and external mechanisms (e.g. volcanism vs. cratering).

Lesson 2: More massive, colder planets are better able to retain atmospheres (e.g., Pluto, Moon, Mercury, Mars, Venus, Earth, Jovian planets, in increasing mass).

ASTR 2310: Chapter 12

Comparative Planetology Lesson 3: Giant satellites of Jovian planets show patterns

consistent with our ideas about formation of the planets (e.g. they're mini-solar systems).

Lesson 4: Many unusual features of the solar system can be attributed to giant impacts (Earth's moon, Triton, Uranus, Venus).

ASTR 2310: Chapter 12

Origin of the Solar System Emerging picture of a rotating protoplanetary disk explains

– Planets nearly in same plane

– Sun's equator is close to this plane.

– Planetary orbits are nearly circular.

– Planets orbit in same direction.

– Most planets and sun rotate in same direction as the orbital motion.

ASTR 2310: Chapter 12

Origin of the Solar System Other issues also addressed

– Nature of small bodies – left overs, with many moons formed around Jovian planets, smallest stuff replenished from collisions

– Differences in chemical composition (metal, stone, ices, volatiles)

– Rings around Jovian planets (failed moons or destroyed moons)

– Chemical differentiation of terrestrial planets (radioactivity)

ASTR 2310: Chapter 12

Exoplanets Detection

– Difficulties

– Center of Mass Wobbles

– Transit Method (eclipses) Properties

– Not quite like solar system planets

• In part because different things can happen

• In part because of selection effects