4769 Castalia & 4179 Toutatis
- Discovered through the use of a new radar technique.
- Images obtained from close-approaching Apollo asteroids.
- Radar waves are bounced off these space-bound objects.
- First used by astronomer Steven Ostro of Cal Tech.
- 4769 Castalia sidcovered in 1989.
- Originally designated as 1989 PB during cataloging.
- Gave a double return when Ostro bounced radar signals off it.
- This echo indicated a dumb-bell shape to the asteroid.
- A crude image was obtainable from the radar signal.
- Castalia is about 1.7 x 1.0 km in size (1,900 x 1,100 yards).
- Castalia's rotation is about 5 hours.
- 4179 Toutalis:
- A photo-like radar image was obtained by Ostro in 1992.
- Toutalis resembles two lumpy, cratered rocks stuck together.
- Toutalis is about 4 x 7 km (2.5 x 4 miles) in size.
- Toutalis' rotation is about 10-11 Earth-days.
- It is the slowest-rotating asteroid known.
- A rocky composition for Toutalis is revealed by spectra.