Notable Asteroids Observed By Ostro Include
- 216 Kleopatra - a large main-belt asteroid, the first asteroid confirmed to have a surface composition of nickel-iron.
- 1986 DA - the first near-Earth asteroid confirmed to be metallic. The estimated amount of platinum-group metals in 1986 DA is comparable to that in the Bushveld Igneous Complex, the largest source on Earth's surface.
- 4769 Castalia - the first near-Earth asteroid imaged well enough to determine its shape, which is two distinct 0.9-km lobes in contact (a contact binary).
- 4179 Toutatis - a contact binary asteroid that is in a non-principal axis rotation state.
- 1998 JM8 - a large near-Earth asteroid that rotates very slowly.
- 1998 KY26 - a very small (30 m wide) asteroid that spins so quickly that it has negative effective gravity.
- 1999 KW4 - one of the first binary near-Earth asteroids known. The shape of the primary (alpha) has been determined by the orbital evolution of the secondary (beta), which is in turn coupled to the system's orbit around the Sun by radiation forces.
- 6489 Golevka - the first asteroid for which the Yarkovsky effect (radiation force changing the orbit) was measured.
In these dynamical studies, Ostro worked extensively with Daniel J. Scheeres of the University of Colorado and his students.
- 1950 DA - an approximately 1-km wide asteroid with a possible Earth impact in 2880 (initially studied by Ostro, Jon Giorgini, Lance Benner, and Scott Hudson).
- 99942 Apophis - a near-Earth asteroid that will pass within geosynchronous orbit in 2029. Radar astrometry from observations by Ostro's group have been essential to predicting Apophis' trajectory.
Radar provides extremely accurate measurement of the positions and velocities of target objects, and such astrometry of near-Earth objects has been recognized as crucial to dealing with the impact hazard. In many cases, radar astrometry has excluded possible Earth impacts from trajectory predictions years before optical astrometry would have been able to do so.
Read more about this topic: Steven J. Ostro
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