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Investigating Sub-KM Sized Asteroids Near Earth: A Comprehensive Study

This workshop led by Bae Young Ho and Byun Yong Ik at Yonsei University focuses on sub-kilometer-sized asteroids near Earth, utilizing data from the SDSS (Sloan Digital Sky Survey). It examines various types of Near-Earth Objects (NEOs) such as NEAs, PHAs, and their orbital dynamics. The presentation covers current search programs, detection challenges, and the characteristics of these asteroids. Innovative stereo observations and advanced detection algorithms are discussed, aiming to enhance our understanding and tracking of potentially hazardous asteroids to protect Earth.

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Investigating Sub-KM Sized Asteroids Near Earth: A Comprehensive Study

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  1. Sub-km sized Asteroids Near the Earth & SDSS data Bae Young Ho & Byun Yong Ik Dept. of Astronomy, Yonsei University SDSS Korean Scientist Group Workshop Feb. 20, 2007 YongPyung

  2. Near-Earth Objects (NEOs) • NECs (Near-Earth Comets) • NEAs (Near-Earth Asteroids) • Atens • Apollos • Amors • PHAs (Potentially Hazardous Asteroids)

  3. Orbit diagram of NEAs • Aten and Apollo cross Earth’s orbit. • Difficult to observe them with ground based telescopes. • But, potentially very dangerous!!! UK NEO Task Force Report, 2000

  4. Goals of NEO Investigation • Study of dynamics and evolution of the Solar System • Study of statistics and dynamics of near-earth asteroids • Detection & tracking of NEO • Contribution to world-wide effort to protect Earth from NEO impacts

  5. Current NEO Search Programs ;International Effort • Lincoln Near-Earth Asteroid Research (LINEAR) • Near-Earth Asteroid Tracking (NEAT) • Spacewatch • Lowell Observatory Near-Earth Object Search (LONEOS) • YSTAR-NEOPAT • Japanese Spaceguard • etc…

  6. Near-Earth Asteroids • q ≤ 1.3AU, Q ≥ 0.983AU • Potentially Hazardous Asteroids(PHAs) • MOID < 0.05AU ~ 20DL • H < 22 • About 20% of NEAs • NEAs > 3km : completed • NEAs > 1km : about 55% by early 2004 • NEAs less than km-sized : ??? C.R.Chapman, Earth and Planetary Science Letters, 222, 2004

  7. The Number of Detected NEAs http://neo.jpl.nasa.gov

  8. Size & Magnitude Distribution of Main Belt Asteroids(2) F.Yosida et. al., Science, 2004, 33

  9. Sub-km sized Asteroids Near the Earth ; The Characteristics • Most of these are of UNKNOWN nature But, we can guess these are • Very Fast !!! • Streaks (tangential direction) • Large parallax during exposure time (direction of sight → stereo observation) • High (apparent) Brightness

  10. SDSS data & YSTAR-NEOPAT • SDSS data • Sky coverage : 8,000 sq. deg.(DR5) • Single-shot & Multi-band Observation • Detection Streak : More Effective to define orbital elements & velocity & distance • Study of Statistics & Velocity Distribution of Sub-km sized Asteroids around the Earth

  11. SDSS data & YSTAR-NEOPAT • YSTAR-NEOPAT • Stereo Observation • More effective on Detection & Define of Orbital Elements & Velocity & Distance • Automatic Steak Detection Algorithm • Already developed, and presently being tested for SDSS image archive • SDSS Mirror Site

  12. YSTAR-NEOPAT System • Small Optics : 0.5m • Shallow Photometric Depth : 17 R at 5σ • Fast Telescope & Open-Type Enclosure • Very Wide FOV : 1.75°X 1.75°

  13. YSTAR-NEOPATSouth Africa Station

  14. Fast Movers in SDSS data http://www.sdss.org

  15. Stereo Observation(1) • Two or more telescopes away from each other • Observing same sky area simultaneously • Measure Parallax / streak on images

  16. Earth Stereo Observation(2) A B Detection of the Sub-km sized Asteroids near the Earth Captured by RAPTOR, Fall 2003

  17. Stereo Observation(3)

  18. Summary • Characteristics of sub-km sized asteroids near the Earth are UNKNOWN !!! • Massive data of SDSS • Streak Detection → study of statistics & velocity distribution • YSTAR-NEOPAT South African Extension • Dedicated Stereo Observations • More effective to define orbital elements • study of statistics & velocity distribution

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