UPDATE! March 02 - Asteroid 2009 DD45 to pass Dangerously Close to Earth

Updated March 2

From Doc Clay:

Note that there is a discrepancy in the elements of the position of new asteroid 2009 DD45
in the current MPEC updates
ftp://cfa-ftp.harvard.edu/pub/MPCORB/
giving positions for this rapidly moving object far (i.e., 60 degrees) north of actual
position. At 12:20 UT the posted elements are showing the asteroid in the constellation
of Hercules.

For 12:28 UT GMT, it is showing:
2009 DD45 mag 13.7
Right ascension: 16h59m33.931s
Declination: +38 08' 10.41"
Mean position at current epoch:
Right ascension: 16h59m52.834s
Declination: +38 07' 22.64"
Apparent position at current epoch:
Right ascension: 16h59m53.343s
Declination: +38 06' 57.41"
Dist from home planet: 0.00114771 AU (171,695 km)
Heliocentric position: lon 161.96634 lat 0.05935
Heliocentric radius 0.99126 AU
52.81% illuminated
Phase angle: 86.78 degrees
Elongation from Sun 93.16 degrees (morning sky)
Speed of apparent motion: 42.504'/hour at position angle 26.9
Motion is -7.69 degrees/day in RA, 15.16 degrees/day in dec
Assumed asteroid diameter 55 meters

whereas the latest MPC Ephemeris provides: ( http://www.cfa.harvard.edu/iau/MPEph/MPEph.html )

2009 DD45 mag 11.7
Period of orbit 1.56 years (571.0 days)
Perihelion distance 0.99 AU
Aphelion distance 1.70 AU
Orbital elements:
Semimajor axis 1.3469988 AU
Eccentricity 0.2642510
Inclination of orbit 13.1721000 degrees
Argument of perihelion 4.0519000 degrees
Long. ascending node 162.0802000 degrees
Mean anomaly 299.3191000 degrees
Epoch of elements JD 2454800.5 (30 Nov 2008 0:00)
Right ascension: 10h25m06.178s
Declination: -48 20' 15.12"
Mean position at current epoch:
Right ascension: 10h25m28.832s
Declination: -48 23' 03.38"
Apparent position at current epoch:
Right ascension: 10h25m31.022s
Declination: -48 23' 12.04"
Dist from home planet: 0.00073555 AU (110,037 km)
Heliocentric position: lon 161.94379 lat -0.03192
Heliocentric radius 0.99161 AU
78.15% illuminated
Phase angle: 55.74 degrees
Elongation from Sun 124.23 degrees (evening sky)
Speed of apparent motion: 10.864/hour at position angle 64.9
Motion is -236.14 degrees/day in RA, 110.49 degrees/day in dec
Assumed asteroid diameter 55 meters

HENCE....please use only http://www.cfa.harvard.edu/iau/MPEph/MPEph.html at this time prior to your observing sessions to determine the exact current elements for this unpredictable object.

IMAGE
NOTE from the image attached that at the "elbow" of its orbit, you can plainly see the streaking "real" path of 2009 DD45 plotted against the predicted path, indicating a substantial shift and unknown amount of error in the predicted positions and path of this speeding object.

Following is used by permission by Southern Stars Observatories;
PLEASE NOTE that the image was not able to be resized in small enough format to reproduce here, but the information from Southern Stars is of interest.
Image were acquired at F84 (Hibiscus Observatory) with the
LX200GPS-14" at prime focus (F/2.0) with a SXV-H9 camera.
IMAGE IS FOUND AT: http://www.planetary.org/image/2009_DD45_20090228_F84.jpg

It is a composite of the images acquired tonight
(2009 March, 1st UT).

You will first note the expected positions from the ephemerids
as they were known at the time of observation, as well as the
strange aspect of the path with a change or about 60 degrees in
the direction, as well as the acceleration as it is closing
toward the Earth.

On purpose, we selected to acquire images around the elbow of
the path, as we expected it will be a significant point for
the orbit improvement.

The NEO trail starts involved with a star a few arcsec
below the point marked 01@07:30 (March, 1st at 07:30 UT).

The true UT time of that first position is 07:55:37 UT,
i.e. an error of 25 minutes, compared to the prediction.

The direction of the real path is also quite different.

The time span, from the first to the last image, is 01h05m.

The measures reported to the MPC, published in the MPEC 2009-E02
provided a dramatic improvement of the orbit of that just
discovered NEO.

One more time, the site of Punaauia (TAHITI) has proved its
high efficiency in the follow-up of hazardous NEO.

On 2009 March, 2nd, 2009 DD45 (a.k.a K09D45D) will fly about
55000 km above the surface of the Earth, at magnitude 10.3,
quite close to the zenith of our Observatories in TAHITI (less
than 11 degrees from the zenith).

At the fastest, its apparent motion will reach 28 arcsec/second
(28 degrees/hour) and it will ends the day high in the Northern
hemisphere.

Noeline TEAMO
Jean-Claude PELLE
Southern Stars Observatories

**************

FROM MARCH 01:

An exciting very close pass of a Near Earth Asteroid for observers in the northern
hemisphere awaits Monday and Tuesday nights; NEO 2009 DD45 will skim within 0.0003 AU of
the earth during the early evening hours of March 1 (2nd UT) and will attain a brightness
of at least mag. 10.8, perhaps brighter.

This object is moving incredibly fast, so charts and preparations will be necessary to
even keep up with it telescopically as it moves rapidly north and east each hour.

For full details and ephemeris information, click:
http://www.cfa.harvard.edu/mpec/K09/K09D80.html
Remember that all times (in decimal days) listed for the object on that link are in Universal Time, NOT local time.

For details on the exact elements to enter into any PC or GO TO program, use the MPC
Ephemeris service at:
http://www.cfa.harvard.edu/iau/MPEph/MPEph.html

This is an incredible opportunity to witness a very, very close pass of a dangerous NEO
toward Earth.

Have fun!

Dr. Clay
_____
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
http://www.arksky.org/