NEO and Space Debris News - 2003

Dec 31 - NEA CENSUS
The Minor Planet Center lists the currently known number of Near Earth Asteroids as 2597. These are distributed among the three orbital classes as:
The number of Potentially Hazardous Asteroids stands at 528

Dec 8 - QUADRANTID PARENT
A possible parent of the Quadrantid meteor shower was identified by P Jenniskens of the NASA Ames Research Center as the recently discovered NEO 2003 EH1. This object, which is most probably a comet, and not an asteroid, seems likely to displace the previous candidate (Comet C/1490 Y1). The Quadrantid meteor stream can only be seen in the northern hemisphere around January 4. It is a very narrow shower, which indicates a young age (possibly only 500 years old). Ref: IAUC Circular No. 8252

Dec 5 - YARKOVSKY EFFECT DETECTED
NASA/JPL scientists observing the asteroid 6489 Golevka by radar over a period of 12 years, have claimed a detection of the Yarkovsky effect for the first time. This effect is due to differential surface temperature (afternoon surface warmer than early morning surface), and provides a very small force on the asteroid which can produce a detectable change in its orbit over many years. Ref: Science, 5 Dec 2003

Dec 1 - DOUBLE IMPACT CRATER FOUND IN LIBYA
French, Japanese and US scientists announced that a double impact crater to be known as Arkenu 1 (6.8km diameter) and Arkenu 2 (10.3km) of age < 140 million years has been located in Libya at N22o 04' and E23o 45'. Originally located using Synthetic Aperture Radar (SAR), the impact nature has been confirmed through the presence of shock structures (eg shatter cones). Ref: Comptes Rendus Geoscience vol 335 pp 1059-1069 (Dec 2003)

Oct 23 - ANOTHER LOST ASTEROID FOUND (1954 XA)
The LINEAR project has recovered 1954 XA. This asteroid has an orbital period of less than a year, and is an Aten class NEO.

Oct 15 - LONG LOST ASTEROID HERMES RECOVERED
The asteroid 1937 UB Hermes was observed in 1937 for only five days before it was lost, not to be seen again until imaged by the LONEOS team this month. Hermes is an Apollo NEO, and passed by Earth on Nov 4 by about 7 million km. Spectroscopic observations have revealed Hermes as an S-type asteroid, and radar observations have shown that it is also a binary asteroid.

Sep 27 - CLOSEST MISS RECORDED (ASTEROID 2003 SQ222)
The asteroid 2003 SQ222 passed by Earth at a distance of only 78,000 km. Its diameter is estimated to be only about 5m (from its measured brightness), and is thus too small to pose any significant threat to the Earth.

Sep 20 - SPACEWATCH DISCOVERS SMALLEST NEO
The aten asteroid 2003 SW130 was discovered by the Spacewatch Project following a pass by Earth at a distance of about 150,000 km. Diameter is estimated in the 5m class. Ref: MPEC 2003-S48

Jul 25-27 - AUSTRALIAN MINOR PLANET WORKSHOP
This event was held at the Port Stephens Marina Resort at Nelson Bay in NSW (about 150 km north of Sydney). IPS was represented by Dr Phil Wilkinson. Perth Observatory was represented by Dr Jamie Biggs, Government Astronomer.

Mar 26 - METEORITE SHOWER OVER ILLINIOS USA
A meteoroid (energy 0.5 to 1 kT TNT) detected by infrasound, and producing a brilliant fireball, dropped hundreds of meteorite fragments (L5 chondrites) onto Park Forest, Illinois. Parent body estimated 10-25 tons and 2m diameter. At least 6 houses and 3 cars damaged. Ref: Sky & Telescope July 2003


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