Ground-Based Near-Earth Object Studies in the post-Russian (Chelyabinsk) Meteor Airburst World

摘要

Public awareness of the danger of potentially hazardous asteroids has been heightened by the airburst of a meteor over Chelyabinsk, Russia, on February 15, 2013, which caused millions of dollars in damage from a shock wave that impacted structures and injured ～1500.people. Later that same day, a larger asteroid, 2012 DA 14,made a close approach to the Earth, but harmlessly skimmed past. Further, other very close-approaching Near-Earth objects (NEOs) have recently posed threats to man-made space assets by passing through or very near the geosynchronous satellite zone. These events have lead to increased awareness and concern, and have subsequently served as a catalyst for deeper exploration of what is being done to mitigate such hazards, and whether more effort needs to be placed in this area of study. An NEO is designated as "potentially hazardous" when its orbit comes to within 0.05 AU of the Earth's orbit. Ground-based physical characterization studies of Near-Earth Objects (NEOs) that are cataloged as potentially hazardous objects (PHOs) are very beneficial to any mitigation plan that might be devised if the risk of impact is high. After a well-defined orbit has been determined for a PHO, other physical parameters such as size, rotation rate, and composition are important. For the smallest PHOs being discovered, observational efforts must commence at or near the time of discovery to ensure favorable parameters for data collection. Otherwise, subsequent optimal apparitions for observing an asteroid or. comet may be decades away.