1. Unexpected planets beyond Pluto their discovery, physical properties, and implications for solar system history David Rabinowitz Yale University, Center for Astronomy and Astrophysics Yale: Charles Baltay, Nancy Ellman, Will Emmet, Tom Hurteau, Rochelle Lauer, Suzanne Tourtellote Indiana University: Jim Musser, Brice Adams, Mark Gebhard Caltech: Michael E. Brown, Kristina Barkume, Henry Roe, A.H. Bouchez, R. Sari, M. van Dam, R. Campbell, J. Chin, S. Hartman, E. Johansson, R. Lafon, D. LeMignant, P. Stomski, D. Summers, P. Wizinowich Gemini Observatory : Chad Trujillo

2. Sedna Quaoar Orcus Pluto (2200 km) 2003 EL61 “Santa” 2005 FY9 “ Easter Bunny ” 2003 UB313 “Xena”

3. Neptune Uranus Saturn

4. ecliptic plane Neptune Uranus Saturn

5. Neptune Le Verrier, Galle 1846, 9” Uranus Herschel, 1781, 6” Pluto Tombaugh, 1930, 13” “Xena” 2005, 48” Kuiper Belt Jewitt, Luu 1992, 86” Sedna 2004, 48”

7. Beta Pictoris

8. M. Liu, Science 303, 2004 AU Mic H-band imaging with Keck Adaptive Optics (0.04” seeing)

9. (0.1 earth mass) Where did the mass go ?

11. Clyde Tombaugh - 1938

12. The reflectance spectrum of 2003 UB313

13. Type of Surface AlbedoDiameterPluto Diameters Fresh snow90%2330 km1.0 Pluto60%2860 km1.3 Charon (Pluto’s moon) 38%3550 km1.5 Most Kuiper Belt Objects 15%5700 km2.4 Possible Sizes for “Xena”

14. Keck discovery of Xena’s moon, “Gabrielle”

15. Easter Bunny Charon Rudolph Santa Xena Gabrielle Keck Laser Guide Star Observations

16. Xena-Gabrielle to Earth-moon Earth Moon Xena Gabrielle XenaGabrielle

17. Santa (2003 EL61) a squashed planet

18. Satellite Discovered around 2003 EL61 (“Santa”) “Santa” “Rudolph”

19. Radius: 49,000 km Period: 49 days Rudolph’s orbit v 2 /r = MG/r 2 M = 4.21x10 21 kg