Solar System Astrometry

1. Solar System Astrometry Carlos E. Lopez Universidad Nac. de San Juan, Argentina, and Yale Southern Observatory

2. Measuring the Positions of: • Asteroids • Comets • Natural Satellites • Space Debris • Occultations

3. Ptolomy’s Solar System

4. Copernicus’s scheme of the Solar System

5. The Solar System Before 1801 (and after the Copenican theory had been accepted) The Solar System on Jan 1st, 1801 Ceres

6. The Solar System as of Jun 8, 2005 around 150,000 objects

7. An Outer Belt? The Kuiper belt is thought to be the source of short-period comets and of centaurs. It is named after Gerard Kuiper who predicted its existence in 1951 but is also sometimes referred to as the Edgeworth-Kuiper belt, in recognition of the amateur astronomer Kenneth Edgeworth (1880-1972) who, in his only scientific paper, published in the Journal of the British Astronomical Association in 1942, was the first to suggest the existence of a region of comet-like objects beyond the outer planets. The first observational support for it came in 1992 when David Jewitt of the University of Hawaii and Jane Luu of the University of California, Berkeley discovered a 200-kilometer-wide object circling the Sun beyond the orbit of Pluto.

8. Orbit of 1996 TL66

9. The Outer Solar System by the End of 1999

10. How many TNOs have been identified so far? • As of Jul 12, 890 objects have been identified. It is assumed there must be on the order of 70,000 such objects. • The first TNO ever discovered was 1992 QB1. • The last one to be discovered was 2005 JR179.

12. Discovery rate 1 1999 16794 1 2000 25330 1 2001 13296 1 2002 5597 1 2003 1055 1847 3 2004 260

13. The name of an Asteroid could be: • Temporary • Provisional • Permanent

14. Provisional Designations

15. Provisional Designations (cont.) • If there are more than 25 discoveries in any one half-month period, the second letter is recycled and a numeral `1' is added to the end of the designation. If more than 50 discoveries, the second-letter is again recycled, with a numeral ‘2' appended after the second letter. Discoveries 76-100 have numeral ‘3' added, numbers 101-125 numeral `4', etc. When possible, these additional numbers should be indicated using subscript characters. • Thus the order of assignment of designations in a particular half-month period is as follows: 1995 SA, 1995 SB, ..., 1995 SY, 1995 SZ, 1995 SA1, ..., 1995 SZ1, 1995 SA2, ..., 1995 SZ9, 1995 SA10, etc.

16. The provisional designations stored on the orbit and observations is stored in a 7-character packed format J95X00A = 1995 XA J95X01L = 1995 XL1 J95F13B = 1995 FB13 J98SA8Q = 1998 SQ108 J98SC7V = 1998 SV127 J98SG2S = 1998 SS162 K99AJ3Z = 2099 AZ193

17. From temporary to provisional designations • 2005 OH = 5O5604D(July 20.49 UT) • 2005 OE = 5O3EC49(July 19.47 UT) • 2005 OB = 77G001 (July 18.37 UT) • 5NA1C16 does not exist (July 17.93 UT) • P03DDA does not exist (July 17.49 UT) • 2005 NP82 = 5N5545E(July 17.49 UT) • 2005 NW80 = SW40Pz (July 16.66 UT) • 2005 NV80 = UHAZ01 (July 16.66 UT)

18. Asteroids: Areas for Study • Shape and Structure • Composition • Mass • Surface Structure • Moons • Magnetometry

19. Classification of Asteroids The classification can be made from two very different points of view: • Physical characteristics • Location within the Solar System

20. Physical Characteristics (main classes only) C class: they have a dark appearance, implying a composition of rocky material mixed with dark carbon compounds.This class is thought to consist of primitive matter. S class: this is a rather small group –compared with the C ones. They are more reflective and show a preponderance of silicate rock.This is the S class, which stands for stony class. M class: this group consists of bodies with large amounts of metal, such as iron and nickel.Apparently these asteroids come from differentiated bodies that have fractured by collisions. V class: a small number of asteroids have basaltic surfaces. These basaltic asteroids evidently had great flows of lava. D class: a few asteroids having a dark surface. In fact the surface of many of these is dark red. Several of these asteroids, beyond the orbits of Saturn, are called Centaur asteroids.

21. Distribution of Inclinations

22. Kirkwood Gaps

23. Dsitribution of the Lagrangian Points

24. The Inner Most Solar System Venus Mercury Sun Earth Mars

26. Classification of NEAs

27. Conversion Between Absolute Magnitude (H) and Diameter H Diameter H Diameter H Diameter

28. The Beginning "The potential catastrophe of an asteroid hitting Earth should no longer be ignored. We need to know what is out there. Accounts of asteroids passing close to Earth with almost no prior warning should be enough to get our attention. The first step is to assess the threat. Given the vast number of asteroids and comets that inhabit the Earth's neighborhood, greater efforts for tracking and monitoring these objects are critical. This bill would direct NASA to expand their current program to track and detect potential threats and would provide a funding authorization. Any threat that would wreak havoc on or world should be studied and prevented if possible. We have the technology, we need the direction - this bill provides that." Rep. Rohrabacher

29. The Beginning (cont.) "All of these bills will improve our lives through increasing our understanding of the Earth, how it works and what may threaten it." Science Committee Chairman Sherwood Boehlert

30. Search Programs

32. The Discovery Channel Telescope

37. The only requirements for participation in the FMO project are 1) interest, 2) sharp eyes and 3) access to a computer during the hours that the Spacewatch mosaic system is in operation. If you are interested in participating, please refer to How to Find FMOs for more information.

42. The Ritcher’s Scale of Asteroid Impacts

43. Upcoming Ecounters

46. How Many NEAs are there? • 286 Atens • 1662 Apollos • 1471 Amors

47. IAU Minor Planet Center

48. IAU Minor Planet Center

49. IAU Minor Planet Center

50. IAU Minor Planet Center