The Possible Comet Pair of May 31, 2003



The pair of objects found by Pavel Shkreby and I,
at 0230 UT on May 31, 2003. Pavel's
is between the hashmarks at the lower left;
mine is to the right. (Images courtesy
the SOHO/LASCO consortium. SOHO is a
project of international cooperation
between ESA and NASA.)


On the night of May 30-31, 2003, I drove with two New York City amateur astronomers, Markus Finkemeier and Richard Rosenberg, up to Wilcox Park, near Rhinebeck, New York, for a star party hosted by the Mid-Hudson Astronomy Association. Unfortunately, the weather did not cooperate; we got a good look at Jupiter, but little else (other than a few tantalizing glimpses of stars before they were covered by stars), though we had a good time talking with the locals. I didnít get home until close to 2 a.m. on the 31st. I logged into SOHO and downloaded the latest images. I noticed, on five consecutive images starting at 0154 UT, a faint speck that by its motion from frame to frame could be a Kreutz comet. However, the images were rather noisy because of a solar storm, and there was a substantial gap in images, between 0254 and 0430 (and no images after that), so it was hard to tell if my object was real or just noise. Nonetheless, I measured the positions, and was pleased to find that they indicated a motion that was surprisingly consistent: a velocity increasing slightly over time, as a true Kreutz comet would as it approached the Sun. I filed a report and then went to sleep.


The two objects at 0354 UT.

The next day I checked, to find out that Russian comet hunter Pavel Shkreby had reported a second comet, not far from mine and running on a parallel track, in three images. (Pavel had actually been looking for my object when he happened across it.) Mike Boschat had [unofficially] confirmed both as comets. No images after 0430 became available; I anxiously awaited them, as it could help verify them as comets. (Pavelís, at least, would need a fourth position to be officially confirmed.)

When Derek Hammer posted confirmations of recent comets, neither mine nor Pavelís were to be seen. I e-mailed Derek, telling him I had expected them to at least become X/comets (comets suspected to be real but unconfirmable due to lack of good positions). He then posted a second note saying he was considering designating mine an X/comet.


The two objects at at 0430 UT. By the next frame,
mine will have disappeared into the brightness above.

On June 4, the missing images from after 0430 were finally posted. I had no trouble tracking Pavelís object in three additional images. Mine, though, had disappeared into a bright solar streamer and never re-emerged. Pavelís did not emerge, either; they both must have tracked upward and slightly to the right through the streamer for a couple of hours before emerging at the streamerís righthand side, by which time they were doubtless too depleted and lost in the bright field to be identified.

On June 25, Derek Hammer declared them both x-comets, with the following explanation: "Reasons include large time gaps between images, a proton storm occurring throughout, and no significant cometary appearance to distinguish from noise, in addition to the fact that the objects are not visible in many images. Also, Pavels' object suggests a medium bright Kreutz comet which I usually can spot in half-res color filter images. However, I saw nothing in the 2:54 image when the object was at its brightest. I never deny a comet due to absence from these images but it does cast doubt...all of these reasons compel me to call both x-comets."

--Tony Hoffman


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