NEO and Space Debris News - 2004

Dec 31 - NEA CENSUS
The Minor Planet Center lists the currently known number of Near Earth Asteroids as 3131. These are distributed among the three orbital classes as:
The number of Potentially Hazardous Asteroids stands at 620

Dec 19 - 2004 YD5 CLOSE APPROACH
Asteroid 2004 YD5 came within geosynchronous orbital radius on December 19. Its closest distance to the centre of the Earth (33,800 km) was at 2038 UT. The most likely size for this asteroid is around 5m diameter. Thus, although it approached the Earth closer than did asteroid 2004 FH on March 18, it is only about 1/200 the mass (most probable mass is about 150 tons), and would have posed only a very minor local hazard had it actually hit the Earth. It is however, only the second object with a computed orbit to travel below geosynchronous orbit altitude.

Dec 16 - 2004 XB45 THROUGH CISLUNAR SPACE
At 1912 UT asteroid 2004 XB45 passed 325,000 km from the Earth. Most probable size of this body is around 12m.

November - AIAA RELEASES NEO PROTECTION PAPER
The American Institute of Aeronautics and Astronautics releases a Position Paper on Protecting the Earth from Asteroids and Comets. See the NEO Reference Material for the download URL (a pdf file).

Oct 24 - 2004 UH1 THROUGH CISLUNAR SPACE
At 1731 UT asteroid 2004 UH1 passed 296,000 km from the Earth. Most probable size of this body is around 7m.

Sep 13 & 21 - TWO PASSAGES JUST INSIDE CISLUNAR SPACE
On the 13th asteroid 2004 RU109,and on the 21st asteroid 2004 ST26 just came within cislunar space. Both bodies are probably around 15m in diameter.

August - COMET PIONEER DIES
Fred Whipple dies at the age of 97. He proposed the "dirty snowball" theory of comets in 1950, a theory that is still accepted today. Among many other distinguished events in his life, he also discovered six comets that were named after him.

Jul 16 - 2004 OD4 THROUGH CISLUNAR SPACE
At 0502 UT asteroid 2004 OD4 passed 165,000 km from the Earth. Most probable size of this body is around 12m. Observation of this asteroid was not made until after the time of closest approach.

Jul 01 - NEA CENSUS
The Minor Planet Center lists the currently known number of Near Earth Asteroids as 2871. These are distributed among the three orbital classes as:
The number of Potentially Hazardous Asteroids stands at 573

Jun 12 - METEORITE DAMAGES HOME IN NEW ZEALAND
A meteorite crashed through the roof of an Auckland, New Zealand home at 9:30 am local time. The meteorite weighed 1.3 kg. A graph showing a simulation of the event is shown here .

May 13 - PERMIAN EXTINCTION CRATER OFF NORTHWEST AUSTRALIA ?
A research group from the University of California at Santa Barbara claims that it has located a crater connected with the Permian Mass Extinction Event of 250 million years ago, when 70 to 90 percent of all terrestrial fauna was wiped out. The geological feature (called the Bedout High) they have identified as an impact crater is located about 200km off the north west coast of Western Australia. However, Australian geologist and impact crater expert Andrew Glikson of the Australian National University disputes that this structure is in fact due to an asteroid impact.

May 10 - LONEOS DISCOVERS ASTEROID WITH SMALLEST ORBIT
Asteroid 2004 JG6 passes inside the orbit of Mercury. With a perihelion distance of only 0.29 AU (Astronomical Units), and an aphelion distance of 0.97, it takes only a little over 6 months to orbit the Sun - the fastest orbiting asteroid currently known. It has an orbital inclination of 19 degrees (to the plane of the ecliptic).

April - SIDING SPRING NEO SURVEY COMMENCES
In conjunction with the Research School of Astronomy of the Australian National University, and using a NASA grant, the Catalina Sky Survey [CSS](University of Arizona LPL) has commenced a southern NEO survey program at Siding Spring, in the middle of New South Wales. The telescope used is the Uppsala 0.5m Schmidt outfitted with hardware and software developed by CSS.

Mar 31 - 2004 FU162 A VERY CLOSE ENCOUNTER
The closest encounter in March was made by asteroid 2004 FU162, which passed within 12,900 km of the centre of the Earth at 1536 UT. However, this fact was not realised until much later. The Linear team made four observations of this object between 0639 UT and 0724 UT. By the time the object was reported to the Minor Planet Center it had moved into the daytime sky and could not be observed again. Steve Chesley of JPL computed the orbit, but it was not until August 22 that the MPC issued an electronic circular designating the object as asteroid 2004 FU162. Its most probable size is around 5m diameter.

Mar 27 - 2004 FY15 THROUGH CISLUNAR SPACE
At 2024 UT asteroid 2004 FY15 passed 240,000 km from the Earth. Most probable size of this body is around 15m.

Mar 18 - CLOSEST PREDICTED APPROACH
Asteroid 2004 FH passed within 42,000 km of the Earth's surface just before 22:00 Universal Time. Although this is not the nearest miss distance recorded for an asteroid(one was filmed passing through the Earth's atmosphere before heading back to space three decades ago), it is the closest approach of an asteroid that had been observed before the approach. The asteroid is believed to be about 30 metres in diameter. The miss distance is just above the geosynchronous satellite belt at a height of 36,000 km. When at its closest approach, asteroid 2004 FH was above the south atlantic ocean, about 1500 km west of South Africa.

Feb 23-26 - PLANETARY DEFENSE CONFERENCE
A conference on Planetary Defense was held at Garden Grove, Orange County, California under the auspices of the AIAA (American Institute of Aeronautics and Astronautics). The conference provided an overview of the threats and current capabilities for providing warning of incoming asteroids and comets by considering various impacts scenarios of different bodies with different fictional impact times. The conference also focused on policy issues and discussions of how nations might prepare for potential impact disasters.

Jan - SKY & TELESCOPE POSITION
In the January issue of Sky and Telescope the editor gave notice to the NEO community that his magazine would only report on Near Earth Objects with a rating of 2 or greater on the Torino scale (unless the object was visible by backyard telescopes).


ASAAustralian Space Academy