The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done & updated

• The recovery of 2000 EV70
• News briefs – readings & Rosetta
• Risk monitoring

Cover: This stack of 57 30-second exposures is from Peter Birtwhistle's 2000 EV70 recovery confirmation from Great Shefford Observatory in England yesterday morning. The individual frames were stacked on the motion of the faint object, thus the background stars appear as long streaks. See more about this recovery yesterday and below.

The following is adapted with permission from an item posted to the Spacewatch FMO (FMO) Project internal News page aimed at project members ("reviewers") rather than geared to the general public.–Ed.

FMO Project Milestone: First PHA Recovery!

2000 EV70, a potentially hazardous asteroid (PHA) not seen since 2000 April 23, was recovered 2004 March 1 in a Mosaic Camera image by Peter Lake, a reviewer from Melbourne, Australia! As it was notably off its predicted position, a second night was necessary before the Minor Planet Center could publish an orbital update. To facilitate the acquisition of a second night, the MPC added the object to its Confirmation Page.

This object was a deliberate recovery attempt by Spacewatch. Because of the object's high uncertainty, the mosaic's large field of view was ideal for the recovery attempt. As a deliberate recovery, the time delay between images was drastically shortened — less than 10 minutes versus the typical 40 minutes. In normal operation, this object would have appeared in

Spacewatch 0.9m telescope 2000 EV70 recovery images from 1 March 2004. ©Copyright Spacewatch FMO.

only one mosaic image instead of three.

As a 19 V magnitude object trailing a mere 10 pixels, this was a difficult catch. The FMO Project Web site is designed to recover 14 pixel trails or longer. Kudos to Peter on his sharp eye!

On March 2, 2000 EV70 received an orbital adjustment in MPEC 2004-E11. Congratulations Peter!

Anne Descour, a University of Arizona Senior Systems Programmer and Spacewatch associate, notes that the point about visibility in three passes and unusual timing is stressed in the original news item because image reviewers have been instructed normally that, "if the 'candidate' FMO is visible in all three passes it cannot be real."

Left: Robert Hutsebaut caught 2000 EV70 yesterday using a remote-controlled telescope at New Mexico Skies, reported in today's Daily Orbit Update MPEC. See yesterday and above about recovery confirmation.

Readings:  The Independent of England has nice review today of current knowledge about the role of planetoids, asteroids, and comets in the formation of the Earth-Moon system and the beginning of life. And Space.com yesterday reviewed what's beginning to be learned about dust disks around nearby stars with evidence for asteroid, comet, and planet-forming activity there.

Astrobiology Magazine has an article today, "Hours to Impact," retelling again the story of 2004 AS1. For more about that, see A/CC's February 9th report and the Major News Index for more news links.

Rosetta:  The European Space Agency has a news item today, "The making of an Ariane 5 launch," telling how, in "a grand symphony of human effort . . . around 200 people have worked for months to bring three critical elements of the launch to readiness at the same time. . .  the launch vehicle, the Rosetta spacecraft and the launch base." It notes that this "was the first time Ariane 5 had placed a spacecraft onto an Earth-escape trajectory," and so "an unprecedented delayed ignition of the Ariane 5 upper stage was needed."

“ Considering the hundreds of millions of kilometres that Rosetta will eventually travel to reach Comet 67P/Churyumov-Gerasimenko, it may at first seem strange that 99.8% of the propellant needed for the mission is consumed during the first hundred kilometres. ”

There seems to be some confusion at large about the name of the Rosetta lander. One astronomy site, for instance, has a routine news item about yesterday's launch that says, "Rosetta's lander, named Ptolemy." The lander was named Philae on February 5th. Ptolemy is an Open University instrument aboard the lander.

Risk monitoring 3 March

The two objects with impact solutions currently under active observation and analysis are not among the ten objects with new 2004 astrometry reported in the Wednesday Daily Orbit Update MPEC.

Update:  Using the existing set of observations, JPL today reissued its risk assessment for 2004 DC before and after midnight UTC, first adding impact solutions and raising risk ratings, then removing solutions and lowering ratings. When compared with Monday's assessment based on this data set, there is a net slight decrease in JPL's overall risk assessment for this already low-rated object.