next up previous
Next: Prospects of future studies Up: Fast Rotating Asteroids 1999 TY2, SF10, WB2 Previous: Discussion

Conclusions

The fast rotations of the three asteroids are evidence that they are monolithic bodies rotating under tension. In fact, the five smallest asteroids with known periods are the fastest rotating asteroids known. This gives significant support to the hypothesis by Pravec and Harris (1999), based on the distribution of asteroid spin rate vs. size, that the transition region between rubble piles and monoliths is around an asteroid diameter of 200 meters. The location of this transition size, which corresponds to an absolute magnitude of , is further supported by the numerical simulations of Love and Ahrens (1996) and Melosh and Ryan (1997).

Further studies of other small, fast rotating asteroids are needed to provide data necessary for understanding of their nature and development of theories of their creation and evolution. A few specific questions that need to be answered by further observations: What is a true distribution of spin rates of a few ten to a few hundred meter sized monolithic asteroids? Is the distribution and the mean spin rate of 200 rot/day (1 rotation per 7 minutes, formal error 50%) of the known sample representative of the whole monolithic asteroid population? What is a dependence of the mean spin rate vs. size? Is there a spin rate correlation to taxonomic type and/or tensile strength of the parent body? These and other questions have to be answered by further observations. Their prospects are outlined in the Appendix.


next up previous
Next: Prospects of future studies Up: Fast Rotating Asteroids 1999 TY2, SF10, WB2 Previous: Discussion