Our Solar System & Exoplanets
(Chapter 15)
Student Learning Objectives
• Identify and locate
objects in our solar
system
• Describe planet
formation processes
• Explain how exoplanets
are found.
What are the main characteristics of our solar system?
All of the objects in our
solar system formed at
about the same time.
4.5 Billion Years Ago
Objects in our solar
system revolve and
rotate counterclockwise
as viewed from above
Venus rotates
backwards
Uranus rotates on its
side
Our Solar System
Our solar system has one star, the Sun.
Planets orbit the Sun.
Moons orbit the planets.
Dwarf planets orbit the Sun.
Asteroids and Comets orbit the Sun.
Practice
1) How many stars are within our solar system?
2) How many moons do you think there are in
our solar system?
3) List the planets in order from the Sun
outward.
What is the process of planet formation?
Planets form in a disk of
rotating gas and dust
surrounding a forming
star.
Solar Nebula Theory
Condensation
Accretion
Planetesimals
Proto-planets
Planets
Two Zones develop during the condensation phase.
Near & Far from Sun
Metals
Far from Sun
Ices
Iron
Water
Methane
Ammonia
Silicates
Original
Cloud
Spins
Faster
As It
Contracts
Flattened
Disk
Of
Planets
2nd Stage Planet Formation
Migration
Differentiation
Atmosphere
Clearing of the Nebula
Bombardment
Atmosphere & Leftovers
Atmospheres form on
some solid planets.
Outgassing/Volcanism
Gravity
Comet Impacts
Leftover planetesimals
become moons,
asteroids, & comets.
Large planets capture
atmosphere.
Phobos
Practice
1) Why is the motion of
objects in our solar
system relatively
uniform?
3) What two factors
determine whether a
planet has an
atmosphere?
2) What determines the
two zones?
4) Why does Earth have
an abundance of
oxygen?
How do astronomers search for extra-solar planets?
Gravity
Eclipses
Microlensing
Direct Imaging
http://kepler.nasa.gov/
http://planetquest.jpl.nasa.gov/ (number of exoplanets)
Gravitational Wobble
Gravity causes a star to wobble.
The wobble causes a Doppler Effect.
Transits
Transits cause some starlight to be eclipsed.
http://kepler.nasa.gov/Mission/discoveries/
Microlensing
Light follows the curvature of space.
Direct Imaging
Space telescopes "see" planets
Gemini Planet
Imager
Beta Pictoris b is a giant
planet – several times
larger than Jupiter –
and is approximately ten
million years old.
(January 2014)
Direct Image
of an Exo-planet
155 LY Away
by David Dickinson
May 14, 2014
1st Habitable Zone planet observed (2010)
Question: What is the Habitable Zone?
Kepler 11
NASA's
Kepler
Mission
Discovers a
World
Orbiting
2 Stars
(September 2011)
Kepler 16
NASA's Kepler Telescope
Discovers First Earth-Size Planet in Habitable Zone
(April 2014)
Practice
Astronomers are searching for
planets around stars like our Sun.
Why?