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Re: (meteorobs) Too quick to do science


MINOR PLANET 1999 RQ36

On September 11th, the LINEAR 1-meter robotic camera in
Socorro, New Mexico, operated by MIT's Lincoln Laboratory,
caught the first images of a 15th-magnitude asteroid with
unusually rapid motion in the constellation Sculptor. The Minor
Planet Center at the Smithsonian Astrophysical Observatory
immediately posted this information on its Near-Earth Object
Confirmation Page, and during the next three days 11 other
astrometric stations operated by amateur and professional
astronomers in Europe, Australia, South America, as well as
the United States responded with more than 50 follow-up
observations. These allowed the MPC's associate director,
Gareth V. Williams, to compute a preliminary orbit and designate
the object 1999 RQ36. 

Probably less than half a kilometer across, this object should
continue to brighten as it moves from Fornax into Eridanus in
the next week or so. According to Williams's orbit, it will pass
only 0.015 astronomical unit from Earth -- about 6 times the
Moon's distance -- around September 23rd. At that time it will be
about magnitude 13.9, similar to Pluto's brightness, as it races
northeastward across Orion near the bright star Betelgeuse.  

While this event does not really qualify as a "near miss" (a handful
of minor planets pass this close to Earth in any given year), the
low-inclination orbit calculated by Williams suggests the object
could come considerably nearer during some future revolution. But it
is much too early to make any definite prediction, because
1999 RQ36 has not been observed long enough to calculate a
definitive orbit. Continued monitoring during the next few months
will help astronomers assess the situation further.

While asteroids of 14th or 15th magnitude are hard to spot visually
in telescopes smaller than 10- or 12 inch aperture, they are easy
to image with a CCD camera on an 8-inch instrument. The following
ephemeris gives the object's coordinates at about 0 hours Universal
Time on successive nights.


                1999 RQ36     

   Date       R. A. (2000) Decl.        Mag.
1999 09 09    01 23.4    -27 57         15.6
1999 09 10    01 28.9    -27 38         15.5
1999 09 11    01 35.2    -27 13         15.3
1999 09 12    01 42.3    -26 43         15.2
1999 09 13    01 50.5    -26 04         15.0
1999 09 14    02 00.1    -25 16         14.8
1999 09 15    02 11.5    -24 13         14.7
1999 09 16    02 250    -22 51         14.5
1999 09 17    02 41.5    -21 02         14.3
1999 09 18    03 01.5    -18 36         14.1
1999 09 19    03 26.3    -15 18         14.0
1999 09 20    03 56.7    -10 50         13.9
1999 09 21    04 33.7    -04 58         13.9
1999 09 22    05 17.0    +02 12         14.1
1999 09 23    06 04.7    +09 56         14.5
1999 09 24    06 53.3    +17 01         15.0
1999 09 25    07 38.6    +22 34         15.7


The announcement was made on Minor Planet Electronic
Circular 1999-R44, issued today by the Minor Planet
Center, Smithsonian Astrophysical Observatory,
Cambridge, Mass., U.S.A.  The above information has been
adapted from that circular, which has further details of
the discovery (http://cfa-www.harvarddot edu/iau/mpc.html).

The editors of Sky & Telescope magazine are interested in
receiving reports and images of this object for possible
publication, either in the magazine (P.O. Box 9111, Belmont,
Mass. 02478, U.S.A.) or on our Web site at www.skypub.com. 

Roger W. Sinnott
Associate Editor
Sky & Telescope
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