[meteorite-list] Asteroid 2005 YU55 to Approach Earth on November 8, 2011

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 10 Mar 2011 14:54:25 -0800 (PST)
Message-ID: <201103102254.p2AMsPsn021871_at_zagami.jpl.nasa.gov>

http://neo.jpl.nasa.gov/news/news171.html

Asteroid 2005 YU55 to Approach Earth on November 8, 2011
Don Yeomans, Lance Benner and Jon Giorgini
Jet Propulsion Laboratory
March 10, 2011

[Graphic/Animation]
Trajectory of Asteroid 2005 YU55 - November 8-9, 2011

Near-Earth asteroid 2005 YU55 will pass within 0.85 lunar distances from
the Earth on November 8, 2011. The upcoming close approach by this
relatively large 400 meter-sized, C-type asteroid presents an excellent
opportunity for synergistic ground-based observations including optical,
near infrared and radar data. The attached animated illustration shows
the Earth and moon flyby geometry for November 8th and 9th when the
object will reach a visual brightness of 11th magnitude and should be
easily visible to observers in the northern and southern hemispheres.
The closest approach to Earth and the Moon will be respectively 0.00217
AU and 0.00160 AU on 2011 November 8 at 23:28 and November 9 at 07:13 UT.

Discovered December 28, 2005 by Robert McMillan of the Spacewatch
Program near Tucson Arizona, the object has been previously observed by
Mike Nolan, Ellen Howell and colleagues with the Arecibo radar on April
19-21, 2010 and shown to be a very dark, nearly spherical object 400
meters in diameter. Because of its approximate 20-hour rotation period,
ideal radar observations should include tracks that are 8 hours or
longer on multiple dates at Goldstone (November 3-11) and when the
object enters Arecibo's observing window on November 8th.

Using the Goldstone radar operating in a relatively new "chirp" mode,
the November 2011 radar opportunity could result in a shape model
reconstruction with a resolution of as fine as 4 meters. Several days of
high resolution imaging (about 7.5 meters) are also planned at Arecibo.
As well as aiding the interpretation of the radar observations,
collaborative visual and near infrared observations could define the
object's rotation characteristics and provide constraints upon the
nature of the object's surface roughness and mineral composition.

Since the asteroid will approach the Earth from the sunward direction,
it will be a daylight object until the time of closest approach. The
best time for new ground-based optical and infrared observations will be
late in the day on November 8, after 21:00 hours UT from the eastern
Atlantic and western Africa zone. A few hours after its close Earth
approach, it will become generally accessible for optical and near-IR
observations but will provide a challenging target because of its rapid
motion across the sky.

Although classified as a potentially hazardous object, 2005 YU55 poses
no threat of an Earth collision over at least the next 100 years.
However, this will be the closest approach to date by an object this
large that we know about in advance and an event of this type will not
happen again until 2028 when asteroid (153814) 2001 WN5 will pass to
within 0.6 lunar distances.
Received on Thu 10 Mar 2011 05:54:25 PM PST