Comets, more comets!

Click on the image for a larger version

The LASCO C2 image above shows the "Sister comets" and their "shadow" images, enclosed in white boxes. The shadow images are in fact the negative image of the comets in the previous LASCO image, an "artifact" (or convenience!) of the running difference technique used to spot faint details in LASCO time series. Also available: GIF animation, MPEGs: Small, Full size.

Caption: After a recent flurry of new discoveries in both real-time and archival images, the LASCO comet count is now (unofficially, 10 July 2000) up to 176, only 5 months after the 100th comet was identified! The official (confirmed) count is now 146. An amateur astronomer, Michael Oates, now has 31 confirmed comets credited to him, compared to SOHO team member Doug Biesecker's 47.

One of the reasons for the rapid discovery rate is the fact that new analyses of comet lightcurves have revealed that LASCO C2 images are more useful for discovering comets than previously thought, especially during May-July. This has caused a very successfull "archive hunt" for previously undiscovered comets, since LASCO C3 images have been the subject of the most scrutiny so far.

Related links:

• Sungrazer site with updated information on SOHO comets, in the What's New area. Also see the announcement from Doug Biesecker on 29 June 2000.
• NASA Science News story.
• SOHO Comet 100 Hot Shot.

Picture Credit: SOHO/LASCO (ESA & NASA)
Instrument/observatories: LASCO (Large Angle and Spectrometric Coronagraph);
Taken: 28 May 1998
Special thanks to Doug Biesecker for maintaining the Sungrazer site and providing these images.