1. Binaries in the Vesta Family of Asteroids William H. Ryan (NM Tech/MRO) Eileen V. Ryan (NM Tech/MRO) Carlos Martinez (UNM)

2. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Project Background: Multi-apparition Photometric study of Vesta family (asteroids dynamically and chemically linked to Vesta) Motivation – Difficulty modeling Vesta family (and other families) formation from cratering impact event (Melosh and E. Ryan, 1997; Asphaug 1997) Other Student Observers during lifetime of project: Amanda Roybal Lawrence Tafoya Lacey Stewart Facility used: 1.8 m Vatican Advanced Technology Telescope (thanks to VORG, Matt Nelson, & Randy Swift)

3. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium September 2001

4. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium December 2002

5. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium December 2002

6. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium December 2002

7. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium January 2003

8. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium January 2003: Composite

9. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium January 2003 (Residuals)

10. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium January 2003 (Late Jan. residuals)

11. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium January 2003 (Intensity Subtraction)

12. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Analysis of 5 Jan. 2003 Event mm  t plat  t tot

13. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Analysis of 5 Jan. 2003 Event dpdp dsds a 

14. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Analysis of 5 Jan. 2003 Event  dpdp dsds a

15. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Summary: 3782 Celle Binary System Secondary/Primary diameters = 0. .01 Primary Diameter ~ 6 km (H ~ 12.5) Primary Rotational Period = 3.84 hours Orbital Period = 36.57  0.03 hours Semi-major axis/primary diameter = 3.4 .2 Mean density = 2.3 .4 g/cm 3 (Basalt ~ 2.9 g/cm 3 HED Meteorites ~ 2.9-3.3 g/cm 3 )

16. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Binary primaries – Spin vs. Size (Courtesy Petr Pravec)

17. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Binary primaries – Amplitude vs. Spin (Courtesy Petr Pravec)

18. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Binary Asteroids (Courtesy Petr Pravec)

19. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Types of Asteroid Satellites (Courtesy Dan Durda, SWRI)

20. Socorro, NM October 3, 2003 19 th Annual New Mexico Symposium Binary Formation Mechanisms:  Vesta impact relic - EEB (Durda, et. al., 2003)  Tidal Disruption (Bottke and Melosh, 1996)  Rotational Fragmentation (Giblin, Petit, and Farinella, 1998)  Secondary Impact?? Observe again next apparition (2004) at different geometry to confirm/refine model parameters