[meteorite-list] Update: Asteroid 136849 approaching (over 1 km in diameter)

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Sat, 17 Jan 2009 12:27:03 -0800 (PST)
Message-ID: <976696.46480.qm_at_web36907.mail.mud.yahoo.com>

Hi Doug, all,

Thanks for the update. I hope as well that the confusion over Arecibo operations will come to an end with Griffin's departure, in as much as one name mentioned for NASA Adminstrator, Gration, worked with Pete Worden.

I assume the Chinese data came from Purple Mountain, and am puzzled as why
the discovery was attributed to Japanese astronomers. Perhaps it has to do
with data posting times.

E.P. Grondine
Man and Impact in the Americas


Dear List,

Drat's, I was completely rained out and will be again tonight, and then
it head a little too "north" for me. Did anyone see this potential
hammer asteroid inchworming from Ursa Major past Arcturus and towards
Corona Borealis (actually it is thought to be a non-carbonaceous stony
asteroid)?

There is still plenty of time for the next two or three days to see it
as it fades to Pluto brightness from its current status a being visible
through big binoculars or amateur scopes. The actual closest approach
is on January 17 at a couple minutes past 17:00 London time.

There is no chance this asteroid will hit Earth anytime soon, but is a
good illustration of what is being done to track potentially
Earth-threatening objects. Both the Puerto Rico's Arecibo (
http://www.naic.edu/public/the_telescope.htm ) and the Mojave Goldstone
dishes ( http://www.jpl.nasa.gov/images/dsn/goldstone/ ) Gigantic Radio
telescopes, on the NASA/NSF/UStaxpayer payroll, are dedicating serious
time to it to figure out its shape, and whatever else they can glean,
which while an academic question in this century, could help with
strategies to deflect it if necessary at a time in the far
future...Typically I think up to ten asteroids monthly (all PHA's,
potentially hazardous) are within range and under RADAR study at these
installations. It is also a Grrrrreat time to do some spectroscopy on
the relatively intense light detectable from Earth during
this pass.
Basically, taking spectra of the reflected light and analyzing which
colors/wavelengths are strongest to get a handle on the composition.
Can't wait to find out what new is learned.

Hopefully Arecibo stays afloat...:-)

Here are the scheduling pages to see the crunching going on for over a
week of observations (as we speak errr...breathe) to see what is being
done about this object that will pass 11.31 LDs (Lunar Distances) from
Earth:

http://echo.jpl.nasa.gov/asteroids/1998CS1/1998CS1_planning.html

Regarding the distance and its associated dangers - Here is an
illustration of ONE Lunar Distance:

http://tinyurl.com/9vyyty

This is a rather big one and events concerning asteroids this size and
proximity happen at best a a few times a year in a fun year.

A couple of clarifying comments, the info on this web page indicates
the Japanese were the ones who discovered it first, at this place,

http://www.kumakogen.jp/culture/astro/astro_e.html

Well the Japanese data is two days after the Chinese data so I don't
know what's the problem with the crediting of the discovery. Second it
mentions that the asteroid measures 0.9 km in diameter plus/minus a
FACTOR OF TWO. That puts it between 0.5 and 1.8 km in diameter - so it
is very likely to be over 1 km in diameter the catastrophic arbitrary
threshold many talk about.

Best wishes and Great Health,
Doug






      
Received on Sat 17 Jan 2009 03:27:03 PM PST