Eileen V. Ryan (Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology), William H. Ryan (Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology)
Keywords: Astronomy
Abstract:
Periodic asteroids and comets that come within a perihelion distance of 1.3 AU or less are defined as Near-Earth Objects (NEOs). These small bodies are in dynamically favorable positions as potential spacecraft mission targets. As a consequence, space missions to NEOs are underway or in development by several major agencies (e.g., NASA, ESA, JAXA), and recently, a manned mission to an NEO was announced as a NASA goal to be accomplished by the year 2025. Further, NASA has selected the OSIRIS-Rex unmanned spacecraft mission for launch in 2016. The spacecraft will rendezvous with and collect samples from the near-Earth asteroid 1999 RQ36. Ground-based monitoring efforts to find and characterize suitable targets for planned and existing spacecraft missions are in progress and require moderate to large-sized telescopes. Good candidate asteroids must have a well-defined orbit and be of a known spectral type. Knowledge of physical properties such as size, shape, internal structure, rotation rate (and whether the asteroid is tumbling) must also be derived. Acquiring more information about the physical nature of NEOs not only contributes to general scientific pursuits and preparation for spacecraft missions, but is important to better address the threat from dangerous NEOs having Earth-crossing orbits. Researchers at the Magdalena Ridge Observatorys (MRO) 2.4-meter telescope facility have an ongoing, comprehensive program to determine orbital and physical characterization information of newly discovered objects in the near-Earth population. The approach of the program is to leverage nightly astrometric follow-up work to obtain physical data (primarily rotation rates) on the most interesting, recently discovered NEOs, including promising spacecraft targets. This strategy allows one-of-a-kind, real-time access to the study of unique asteroids and comets before they leave the near-Earth vicinity. We will present new data obtained by photometric, spectroscopic, and other techniques on the physical properties of several Earth-approaching asteroids that are potential mission candidates. We will discuss collaborative efforts with researchers using radar to characterize prospective targets, and outline the synergy and increased science return of such an endeavor. In addition, we will present characterization results of the photometric properties of asteroid 1999 RQ36 at visible wavelengths including its rotation rate and phase function. These data were collected during the 2011-2012 apparition of the asteroid, which is the last opportunity for ground-based studies before OSIRIS-Rex is launched.
Date of Conference: September 11-14, 2012
Track: Astronomy