1. Bell work  What do you think the major differences are between a planet and a dwarf planet?

2. Dwarf planets Eris Pluto and Cheron Ceres Our Moon

3. Objectives  Describe the differences between a planet and dwarf planet.  Identify unique characteristics of each dwarf planet.

4. What is a Dwarf Planet?  According to the International Astronomical Union, which sets definitions for planetary science, a dwarf planet is a celestial body that:  Orbits the sun.  Has enough mass to assume a nearly round shape.  Has not cleared the neighborhood around its orbit.  Is not a moon.  The main distinction between a dwarf planet and a planet is that planets have cleared the path around the sun while dwarf planets tend to orbit in zones of similar objects that can cross their path around the sun, such as the asteroid and Kuiper Belts. Dwarf planets also are generally smaller than the planet Mercury.  There are currently five officially recognized dwarf planets. The IAU estimates there may be dozens or even more than 100 dwarf planets awaiting discovery.  The IAU recognized Pluto's special place in our solar system by designating dwarf planets that orbit the sun beyond Neptune as plutoids. Eris, which orbits far beyond Neptune, is a plutoid while Ceres, which orbits in the main asteroid belt between Mars and Jupiter is a dwarf planet.

6. Pluto  Distance from sun-5.4 light-hours  Period of rotation-6 days, 10 h (R)  Period of revolution-*248 years, 4 days  Diameter-2,390 km  Density-1.75 g/cm3  Surface temperature- −225°C  Surface gravity- 6% of Earth's

7. Pluto  In 2006 Pluto was reclassified as a Dwarf planet.  Pluto is smaller than Mercury.

8. Pluto  A Small World  Scientists think that Pluto is covered by frozen nitrogen and has a thin atmosphere of methane. Pluto's moon, Charon (KER uhn), is covered by frozen water and is more than half Pluto's size! In fact, Charon is the largest satellite relative to its planet in the solar system.  Discovered in 1930, Pluto was long considered our solar system's ninth planet. But after the discovery of similar intriguing worlds deeper in the distant Kuiper Belt, icy Pluto was reclassified as a dwarf planet.

9. Ceres Ceres is a dwarf planet located in the inner solar system. It was discovered in Jan. 1801. www.solarsyatem.nasa.gov

10. Distance from the Sun TThe average distance of Ceres from the sun is 257,143,648 miles. Ceres has an eccentric orbit, so its actual distance from the sun will vary.

11. Periods of Rotation and Revolution  The period of revolution: 4 years and 219 days  The period of rotation: 9 hours, 4.5 minutes Jared110.wordpress.com

12. Diameter  The diameter of Ceres is 950 km, or 590 miles. en.wikipedia.org

13. Surface Temperature  For its distance, the Cererian surface is warm. It is -53 degrees Celsius. en.wikipedia.org

14. Ceres’ Atmosphere  No one knows yet if Ceres has an atmosphere or not. Scientists believe Ceres may have a weak atmosphere with frost made of water on the surface.  Ceres only has 4% of Earth’s gravity, so its hard to keep a strong atmosphere. However, water vapor on Ceres may have formed a small protective layer like an atmosphere.  Ceres also gets some solar radiation on the surface. That results in significant amounts of hydroxide in the poles.

15. Surface  Its surface brightness is the same as our moon’s. Scientists believe Ceres has a surface like our moon’s. With many craters and a rocky surface.  However, Ceres is relatively warm, our moon is cold. Since Ceres is a dwarf planet AND an asteroid, Ceres is made of iron, nickel, and metals like most asteroids.  Scientists also believe that a layer of ice- water lay beneath the surface.

16. What makes Ceres unique?  Ceres is named after the Roman goddess of agriculture, grain crops, and motherly love. It is the only dwarf planet in the inner solar system.  Ceres was discovered in 1801 before Pluto and Neptune. It was a considered a planet for 50 years, then reclassified as an asteroid, and then in 2006 as a dwarf planet. Oddly, Ceres only the size of Texas.

17. Objectives  Describe the differences between a planet and dwarf planet.  Identify unique characteristics of each dwarf planet.

22. Makemake  After Eris and Pluto, Makemake is the third largest known dwarf planet. Along with fellow dwarf planets Pluto and Haumea, Makemake is located in the Kuiper Belt. Pluto and Makemake are the two brightest objects that have so far been discovered in the Kuiper Belt.  It takes 310 Earth years for this dwarf planet to make one orbit around the Sun.  Makemake was first observed in 2005 by Michael Brown. It was officially recognized as a dwarf planet by the International Astronomical Union in 2008.  Observations have found evidence of frozen nitrogen on Makemake's surface. Frozen ethane and methane have also been detected on the surface.

23. Haumea  4.4 light-years away  Period of rotation-3 h, 55 min  Period of revolution- 285 years  Temperature= - 241°C  Gravity-0.024% of Earth’s  Moons-Hi’iaka and Namaka

24. Haumea Haumea is spinning so quickly that it has turned into the shape of an ellipsoid. In Hawaiian mythology, Haumea is the goddess of fertility and childbirth. Haumea might not have an atmosphere. Haumea has a dark spot that reflects more red light than blue light, which means it has a reddish tint that is in the visible spectrum. Scientists thing that a reddish object hit haumea, therefore creating a dark, reddish spot.

25. Objectives  Describe the differences between a planet and dwarf planet.  Identify unique characteristics of each dwarf planet.