[BAA 00393] Close-approaching asteroid, 2009 DO111

[Rick]

BAA electronic bulletin No. 00393 -- http://www.britastro.org/

Asteroid 2009 DO111 discovered last month by Steward Observatory, Kitt Peak, appears to be an unusually-shaped object some 100 meters across (approx.) which will pass just 1.22 Lunar Distances (469,000 km) from the Earth on March 20 04h UT.  For UK observers, the object is very well placed for observation up until about 0h UT on the night of March 19/20, when it will have 'accelerated' to an apparent speed of more than 3 arcsec per second and will be about magnitude 12.6-13.0.

Peter Birtwhistle and I have each obtained a series of observations which show that it is rotating extremely rapidly, spinning once every 176 seconds, which puts it into the top-ten fastest known rotators.  Also another unusual feature is the shape of the rotational lightcurve: with each rotation, the brightness appears to take a sudden dip of about 30% where it remains for about 20 seconds or so before brightening up again.  Long exposures when the object is bright should create a trail in which the intensity recorded along the trail will reflect this extremely rapid rotational modulation.  Further observations are encouraged.  Positional details can be found at: http://www.cfa.harvard.edu/iau/MPEph/MPEph.html

See also Minor Planet Center announcement at: http://www.cfa.harvard.edu/mpec/K09/K09E70.html

Clear Skies,

Richard Miles
Director, Asteroids and Remote Planets Section, BAA

[doug]

    Aha...... Rama approaches

[JohnP]

Better get ready for a rendezvous then........

[Ian]

would that be tin foil hats, mass suicides or just putting you head between your legs and kissing your .... goodbye?

[MarkS]

Whereabouts will it be tonight (in the unlikely event of a clear sky) ?

Mark

[Rick]

From the second link in the announcement:

Code Select Expand

Ephemeris:
2009 DO111               a,e,i = 1.05, 0.28, 3                   q = 0.7557
Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
2009 03 19.0  12 03.20   +33 25.9    0.00690  1.001   147.1    32.6    13.2
2009 03 19.5  11 43.70   +47 36.3    0.00472  0.999   132.8    47.0    12.7
2009 03 20.0  09 11.70   +75 54.5    0.00326  0.996   100.7    79.1    12.9
2009 03 20.5  01 30.81   +52 31.8    0.00356  0.994    55.9   123.9    15.5

...from which I deduce it's fair wizzing across the sky.

[MarkS]

So what is that (roughly) in terms of Alt & Az from Sidcup.  i.e. will it be behind a tree?

[Rick]

The http://www.cfa.harvard.edu/iau/MPEph/MPEph.html calculator is being very reluctant to divulge any information, so I suspect there's some uncertainty about the object's orbital elements. However, given that the published prediction has it moving from R.A. 1 43.70 Dec. +47 36.3 to R.A. 09 11.70 Dec. +75 54.5 in 12 hours, I expect the answer to "will it be behind a tree?" is "If so, then not for long...".

The relevant BAA section doesn't have any relevant charts or positions for 2009 D0111...