1. Our Solar System & Exoplanets
(Power Point 07)
Image Credit: Slyavula Education
Image Credit: NASA

2. Student Learning Objectives
Construct a model of the Solar System
Identify and locate objects in our solar system
Describe planet formation processes
Explain how other “solar” systems (exoplanets) are found

3. Source: Solar System Videos

4. 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
Most objects in our solar system revolve and rotate counterclockwise as viewed from above the northern hemisphere.
Venus rotates backwards
Uranus rotates on its side

5. 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.

6. Practice How many stars are within our solar system?
How many moons do you think are in our solar system?
What are the names of the planets, in order, from the Sun outward?
How many other stars in our galaxy have planets?

7. What is the process of planet formation?
Planets form in a disk of rotating gas and dust at the same time the as the star is forming.
Solar Nebula Theory
Condensation Accretion Planetesimals Proto-planets Planets

9. The Protoplanetary Disk of HL Tauri
Image Credit: ALMA (ESO/NAOJ/NRAO), NSF
Image Credit: APOD ALMA (ESO/NAOJ/NRAO), NSF

10. 2 Zones
There are two general zones of condensing materials in the protoplanetary disk.
Near & Far from Sun
Metals
Iron & Silicates
Far from Sun
Ices
Water, Methane, Ammonia

11. Image Credit: NASA

12. Practice Explain the cause of the 2 condensation zones.
Iron has a vaporization temperature of 2870 ºC. Where would you expect iron to condense relative to its star?
Methane boils at −161 ºC (−258 ºF) . In which “zone” will methane condense?

13. The Solar Nebula Theory
By Morgan Gordon

14. Continuing System Formation
Migration Differentiation Atmosphere Clearing of the Nebula Bombardment
Image Credit: NASA

15. Differentiation
Artist rendition of the formation of rocky bodies in the solar system – how they form and differentiate and evolve into terrestrial planets. Image credit: NASA/JPL-Caltech

16. Atmosphere & Leftovers
Atmospheres form on some solid planets.
Outgassing/Volcanism
Comet Impacts
Large planets capture atmosphere before the nebula is cleared.
Leftover planetesimals become moons, asteroids, & comets, and have collisions (bombardment).
Phobos
Image Credit: NASA

17. Practice
Explain why the motion of objects in our solar system is relatively uniform.
What factors would determine whether a planet is able to maintain an atmosphere?
Earth has an abundance of oxygen. Where does earth get its abundance of oxygen?

18. How do astronomers search for other “solar” systems?
Gravity
Eclipses (Light Curves)
Microlensing
Direct Imaging
Image Credit: NASA

19. Gravitational Wobble Gravity causes a star to wobble.
The wobble may result in a Doppler shift.
The wobble may result in astrometric shifts in star position.
Video by ESO

20. Eclipses
When a planet crosses in front of a star (transits), there is a decrease in brightness from the star.
Image Credit: NASA

21. Microlensing Light follows the curvature of space caused by mass(es).
May result in more images on one side than the other.
Image Credit: NASA

22. Microlensing & Brightness
Brightness increases when both planet and star bend the light to the observer.
Source: Hubble Space Telescope

23. Direct Imaging
Image Credit: JPL/NASA

24. Direct Image of Beta Pictoris b
Several times larger than Jupiter
10 Million years old
Image Credit: Gemini Planet Imager January 2014

25. Practice
Does direct imaging provide images of the surface features of an exoplanet? Why?
Have astronomers searched a relatively large or small portion of space for exoplanets?
Which method do you think is used most often by astronomers to find exoplanets?

26. What is the Habitable Zone?
The habitable zone is where liquid water is possible.
Image Credit: NASA Kepler Mission

27. Practice
Where specifically are Earth, Venus, and Mars located relative to the Sun?
Image Credit: NASA

28. Image Credit: NASA

29. The Kepler 11 System
Image Credit: NASA

30. Kepler 16 NASA's Kepler Mission discovers a world orbiting 2 Stars
(September 2011)
Image Credit: NASA

31. First Earth-Size Planet in Habitable Zone (April 2014)
Image Credit: NASA

32. HR 8799 4 super-Jupiters orbiting
Periods range from decades to centuries
Motion based on 7 images taken from the Keck Telescope over 7 years
Movie Credit: Jason Wang and Christian Marois

33. Practice
Astronomers are searching for planets around stars like our Sun. Why?
Particular importance is placed on finding Earth size planets. Why?
Compare and contrast the habitable zone of a red star to the habitable zone for our Sun.