Welcome to the Party! Why are we here?

1. Welcome to the Party!Why are we here? • Celebrate the beginning of Dawn's year-long exploration of new worlds! • Share in the excitement as we see something no one has seen before! • Learn something new!

2. Dawn: Exploring New Worlds DAWN Mission Dawn EPO Teams

3. What will the Dawn Spacecraft do? • Use ion propulsion to explore two asteroids protoplanet • Vesta and Dwarf Planet Ceres, by: • Mapping their surfaces to learn their geology & composition • Determining how and when they formed • And learning the internal and external forces that shaped them • So why did Dawn’s scientists want to look at the asteroid belt? • To explore the earliest stage of our solar system • To understand how planets like ours formed!

4. Why Ceres and Vesta? • Vesta and Ceres are among the largest asteroids and survivors of the formation of the solar system • Vesta was volcanically active like our moon, while Ceres is made of ice and rock like Jupiter’s moons • Studying Ceres & Vesta together tells us about how a planet’s size and distance from the sun affect its formation

5. What is an asteroid, really? • There isn’t a good definition • Generally, a small, rocky body orbiting ~inside the orbit of Jupiter • Most are found in the main belt between Mars & Jupiter (which looks something like this) --> Image credits: NASA/JPL

6. What are Asteroids made of? • Bright, dry, rocky asteroids like Vesta dominate the inner asteroid belt • Dark, hydrated, and icy asteroids like Ceres dominate the outer belt • Ceres and Vesta are big enough to differentiate (have a core like the Earth), and thus are also called “protoplanets”

7. Asteroids come in all shapes & sizes, but protoplanets are nearly round! Ida Eros Vesta Itokawa Ceres Gaspra Pallas 950 km Annefrank Image credits: NASA & STScI (HST)

8. What do we know about Vesta? • Discovered by Heinrich Olbers in March 1807 • Named after the Roman goddess of the hearth • Largest basaltic asteroid • 265 km average radius • Third largest asteroid! • Second most massive • Differentiated • Basaltic (like Hawaii’s volcanoes) • Distinct surface regions • Implies early formation Image credit: STScI (HST)

9. What do we know about Ceres? • Discovered in 1801 by Piazzi • Named after the Roman goddess of agriculture • Largest and brightest body in asteroid belt • Average radius of 950 km • Because: • It has no obvious surface features • We have no meteorites from it! • …it’s probably made of ICE! Image credit: STScI

10. Where is Dawn going? Vesta July 2011 – July 2012 Ceres Feb 2015 – July 2015 Mars Gravity Assist Feb 2009 • At each target, Dawn will: • Acquire color images • Compile a topographic map • Map the elemental composition • Map the mineralogical composition • Measure the gravity field • Search for moons Launch Sep 2007

11. What will Dawn do at Vesta?(Jul ‘11- Jul ‘12) • Explore Vesta using its specialized instrumentation. • Composition will be mapped by Visual Infrared Spectrometer (VIR) and Framing Camera color filters • Topography, impact history and geology will be mapped by the Framing Camera • Elemental abundances will be determined by GRaND • Crustal thickness and interior structure will be determined by gravity from radio science

12. Any Questions? Visit: dawn.jpl.nasa.gov Dawn’s Launch, Sept. 27 2007