We present a new Near Earth Object (NEO) survey simulator which incorporates the four-dimensional population model of 4668 NEOs [Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433] and the observing strategies of most asteroid search programs. With the recent expansion of survey capabilities, previous simulators focused on a specific survey facility are no longer useful in predicting the future detection rates. Our simulation is a superposition of simplified search patterns adopted by all major wide-field surveys in operation in both hemispheres. We defined five different simulation periods to follow the evolution of survey efficiencies reflecting changes in either search volume as a result of upgrades of telescopes and instruments or in observing schedules. The simulator makes remarkably good reproductions of actual survey results as of December 2005, not only the total number of detections but also (a, e, i, H) ('H' means absolute magnitude of an asteroid) distributions. An extended experiment provides excellent predictions for discovery statistics of NEOs (H < 18) reported to the Minor Planet Center in 2006. These support that our simulator is a plausible approximation of real surveys. We further confirm that, with the Bottke et al. [Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433] population model and present survey capability, the 90% completeness level of kilometer-sized NEOs will be achieved by 2010 or 2011. However, about 8% of the kilometer-sized or larger NEOs would remain undetected even after 10-year operation (2007-2016) of all current NEO survey facilities. They are apparently faint, with orbits characterized by large semimajor axis and higher eccentricity; these "hardest-to-find" objects tend to elude the search volume of existing NEO survey facilities. Our simulation suggests that 15% of undetectable objects are Atens and Inner Earth Objects. Because of their orbital characteristics, they will remain within ±45° from the Sun, thus cannot be discovered in the forthcoming decade if our effort is limited to current ground-based telescopes.
Bibliographical noteFunding Information:
We thank Hong-Suh Yim, Se-Heon Oh, William Bottke, Steve Larson, Robert McNaught, and Robert McMillan for valuable comments and input to this study. We also thank referees, Drs. Joseph Scott Stuart and David Tholen, for their suggestions which improved the original draft significantly. H.K.M. acknowledges partial support from the Korea Astronomy and Space Science Institute, Korea Research Council of Fundamental Science and Technology, and also from the Korea Research Foundation Grant funded by the Korean Government (MOEHRD KRF-2005-213-C00020). H.K.M. is also grateful to Mike Bessell and the staff of the Research School of Astronomy and Astrophysics, Mount Stromlo Observatory for their warm hospitality during his visit. Y.I.B. acknowledges the support of SBS Cultural Foundation. S.N.R. was supported by an appointment to the NASA Postdoctoral Program at the University of Colorado Astrobiology Center, administered by Oak Ridge Associated Universities through a contract with NASA.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science