P/2004 WR9 (LINEAR)
|Comet P/2004 WR9 (LINEAR)
2004 Dec 07 00:11 - 01:07 UT
Frames 10 min & 12 min total exposure.
Motion 0.26"/min in p.a. 310°
Faint tail 20" in p.a. 235°
Field 5'x5', binned 2x2 and enlarged x2, scale 3" per pixel
0.30m f/6.3 Schmidt-Cassegrain + CCD
Originally discovered by LINEAR on 2004 Nov 22.3 UT this object had
been reported as asteroidal and already designated as 2004 WR9.
Ten days later, on 2004 Dec 02.94 UT it was posted on the NEO
Confirmation page, presumably after the Minor Planet Center recognised
its orbit as being comet like. By then it was moving very slowly at
16" per hour in Auriga, 2½° North of Beta Tau, in a rich star field
Two separate runs were taken from Great Shefford on 2004 Dec 3.0 UT,
the first for a total of 6½ minutes and the second, 25 minutes later of
4½ minutes and although the object was well recorded and the image
examined for possible cometary detail, no obvious cometary features could
be made out for sure.
The next opportunity to image the object was on 2004 Dec 7.0 UT and
this time a total of 90 twenty second exposures were taken, the exposures
being kept short to stop any drive inaccuracies from blurring the images.
Cloud interfered with about one in three of the images and those that were
OK were then formed into two stacks, the first of 10 minutes total
exposure and the second of 12 minutes (shown in the animation above). A
faint, short tail could just be made out extending to the lower right, a
bright star masking the end of the tail.
The earlier Dec 3.0 images were then re-examined and a hint of a
10" extension to the central condensation was suspected in p.a.
Details were sent to the Minor Planet Center on Dec 7.07 UT along with
the astrometry from the two stacks. IAUC 8448 was published on 2004 Dec
8.73 after Carl Hergenrother had confirmed a similar appearance from
images taken 2004 Dec 08.45 UT with the 1.54-m
Catalina reflector at Mt. Lemmon.
The comet was shown to be arriving at perihelion in early January 2005
at a distance of 1.9 AU with an inclination of just 5° and having a
period of nearly 15 years.