1. Does the Kuiper Belt have an edge? Ming-Chang Liu

2. Introduction Kuiper Belt, a thick band of small bodies beyond the orbit of Neptune, has an extended range from 30 AU to 50 AU. Kuiper Belt, a thick band of small bodies beyond the orbit of Neptune, has an extended range from 30 AU to 50 AU. Importance: It reserves the extremely pristine materials from the early solar system. Furthermore, it ’ s widely accepted as a new home for short-period comets. Importance: It reserves the extremely pristine materials from the early solar system. Furthermore, it ’ s widely accepted as a new home for short-period comets.

3. History Edgeworth & Kuiper. Edgeworth & Kuiper. What happens between 30~50 AU? What happens between 30~50 AU? Hard to detect! Hard to detect! Stern (1996)

4. Discovery of KBOs 1992 Jane Luu and David Jewitt: 1992 QB1, 23 magnitude, 43 AU away. 1992 Jane Luu and David Jewitt: 1992 QB1, 23 magnitude, 43 AU away. Now, more than 900 objects have been found in this region. Now, more than 900 objects have been found in this region.

5. Orbit distributions of KBOs Classical KBO: circular orbit, extending to 50 AU. Some of them have high inclination. (up to 30 degree) Classical KBO: circular orbit, extending to 50 AU. Some of them have high inclination. (up to 30 degree) Scattered KBO: largely eccentric orbit, extending to ~200 AU. Scattered KBO: largely eccentric orbit, extending to ~200 AU. Plutino: in or near the 3:2 mean motion resonance (the same as Pluto) with Neptune. Plutino: in or near the 3:2 mean motion resonance (the same as Pluto) with Neptune. From Jewitt, (2000) Jewitt (1999)

6. The Edge of the Kuiper Belt The classical Kuiper Belt stops at ~ 50 AU. The classical Kuiper Belt stops at ~ 50 AU. But, is this a real edge? But, is this a real edge? Observations show that no object was found beyond ~49 AU. (Trujillo et al., 2001; Allen et al., 2001) Observations show that no object was found beyond ~49 AU. (Trujillo et al., 2001; Allen et al., 2001) Or it ’ s due to the observational limitation to detect (small or faint) objects beyond 50 AU? Or it ’ s due to the observational limitation to detect (small or faint) objects beyond 50 AU?

7. Beyond the Edge What ’ s beyond 50 AU? What ’ s beyond 50 AU? Scattered KBOs. Scattered KBOs. Distant population of small bodies on near-circular orbits with inclination? Distant population of small bodies on near-circular orbits with inclination? If something dwells beyond 50 AU, can we detect them? If something dwells beyond 50 AU, can we detect them? YES!

8. TAOS Taiwan-America Occultation Survey. Taiwan-America Occultation Survey.

9. Conclusion Whether Kuiper Belt has an edge is still uncertain; however, observation results favor the existence of the edge. Whether Kuiper Belt has an edge is still uncertain; however, observation results favor the existence of the edge. But this conclusion may be overthrown! But this conclusion may be overthrown!