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Elongated asteroids

Hello List and Ron,


My original question below from two weeks ago about
determining the composition of asteroid 1999 AN10 , got obscured by
discussions
on magnitude, orbit, and the Yarkovsky effect.  My own fault because I'm all
over the place:-)

Now, with the logical theory presented by  Stephen Wampler, about elongated
asteroids
being weaker,  I want to get back to one of my rainy day questions:

Have we yet determined the composition of 1999 An10 (or the shape)?  Is it
far enough now from the glare of the sun to know it's exact magnitude for
determining it's composition or is there another way to determine
composition at this stage of it's orbit?

An iron, I would
imagine, would have a higher degree of safety with regard stability and
deflecting it away from Earth as a counter measure.  (Bonus points if it is
also spherical:-)

 Further, if it is an iron, couldn't we consider using alternate methods of
deflecting it other than with solid matter,  for example with, say, a
massive repelling magnetic field whose source emanates from a space station
somewhere at a safe distance from the atmosphere?  This is sounding quite
sci-fi and quite 21th century science as well.

Best Regards,
Julia
-----Original Message-----
From: jjswaim <MissionControl@email.msn.com>
To: meteorite-list <meteorite-list@meteoritecentral.com>; Ron Baalke
<BAALKE@kelvin.jpl.nasa.gov>
Date: Thursday, May 20, 1999 10:44 AM
Subject: Re: The Continuing Story of Asteroid 1999 AN10

|A Monsieur Baalke or anyone:
|One question:   Since the visiblity of Asteroid 1999 AN10 has been
|heretofore affected by the glare of the sun and assuming the only way to
|determine what type of asteroid it is (Iron, Stone, Carbonaceous), is by
|brightness, how is it possible to make an accurate prediction as to it's
|orbit
|since I am further assuming the Yarkovsky effect (uneven heating) would
|presumably alter it's velocity, rotation, and ultimately it's orbit,
|differently according to what type it is. (An iron would be affected more
|than a stone due to conducivity.)
|
|Curious,
|Julia
|
|-----Original Message-----
|From: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
|To: meteorite-list@meteoritecentral.com
|<meteorite-list@meteoritecentral.com>
|Date: Tuesday, May 18, 1999 9:33 PM
|Subject: The Continuing Story of Asteroid 1999 AN10
|
|
||The Continuing Story of Asteroid 1999 AN10
||http://http://neo.jpl.nasa.gov/news/news017.html
||
||New observations are now available for asteroid 1999 AN10, which
||is gradually moving away from the glare of the Sun.  The new data
||allow a considerably improved orbit to be calculated for this
||potentially hazardous object, and the revised predictions indicate
||that this kilometer-size asteroid could pass particularly close
||to the Earth on August 7, 2027.  The passage in 2027 could
||be as close as 37,000 km from the Earth's center (just 19,000 miles
||above the Earth's surface), but no closer.  The miss distance is still
very
||uncertain, and the asteroid could easily pass well outside the Moon's
||orbit.  The probability of a collision in 2027 is essentially zero.
||
||The accompanying diagram (http://neo.jpl.nasa.gov/neo/an10.gif) shows the
||uncertainty in the predicted close approach in 2027.  The asteroid must
||pass through the plane of the diagram somewhere within an extremely
||elongated uncertainty ellipse, which appears simply as a line segment.
||(To be precise, the ellipse as drawn is a three-sigma linear confidence
||boundary.)  The center of the ellipse is indicated by the plus sign, which
||is located at a nominal distance of 58,000 km from the center of the
Earth.
||The minimum distance between the ellipse and the Earth center is 37,000
km.
||
||There is still a very remote possibility that asteroid 1999 AN10 could
||pass by Earth in 2027 in such a way as to return in the year 2039 on
||an impacting trajectory.  First identified by researchers
||Andrea Milani, Steven R. Chesley and Giovanni B. Valsecchi, this
||scenario is still exceedingly unlikely, but the probability of collision
||in 2039 has now increased to about 1 chance in 10 million.  The post-2027
||(Monte Carlo) analysis of this object's motion will continue.
||
||Paul W. Chodas
||Research Scientist
||Near Earth Object Program Office
||Jet Propulsion Laboratory
||May 18, 1999
||
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