SOHO/Near-Sun Comet News and Views
This newslog will focus on sungrazing and near-sun
comets, as well as any comets observed in the SOHO (Solar and
Heliospheric Observatory) LASCO coronagraph images, though I will also
include important news items of general interest regarding comets.
July 7, 2008
Bo Zhou just reported a Kreutz comet about halfway from
the edge of the C3 field of view to the Sun. By my count, this is his
99th SOHO comet.
July 4, 2008
I'm sorry I've been remiss in updating these pages. I've
updated the discovery totals (as usual, please e-mail me with any discrepancies) and there's a lot of news to catch up on.
SOHO has now passed the 1,500-comet mark, with Rob Matson finding the
milestone comet, a C2 Kreutz, on June 25. Congratulations to
Rob--though this is really a triumph for us all, and especially for the
NASA and ESA scientists who designed and operate the SOHO spacecraft,
which 13 years after launch is still going strong. Now, on to 2,000!
On June 10, Rainer Kracht recovered the second Kracht2 comet, the
presumed return of C/2002 R5, as well as a small companion. C/2002 R5
was originally found on September 5, 2002 by Rob Matson. The other
known major Kracht2 comet, P/2007 R5, became SOHO's first official
periodic comet when it was spotted last September 10 by Bo Zhou
at its third consecutive perihelion passage. (It had previously
been found in 1999 by Terry Lovejoy and in 2003 by Kazimieras Cernis.)
Speaking of periodic comets, On July 3 I found a Kracht comet that
presumably is the return of C/2002 S7, which had been previously
C/1996 X4. It remains to be seen whether it will officially be
designated a periodic comet.
The count of STEREO comets that have received MPECS is up to 6, with
four found by Alan Watson, and two by Rainer Kracht (who has now found
comets in images from three different space missions: SOLWIND, SOHO,
and STEREO, spread out over more than 25 years of data).
Three very bright Kreutz comets have been seen in LASCO over the past
couple of months.. The first, found by Rob Matson on May 21, was
extremely bright, one of the brightest seen in SOHO. Its tail lingered
long after the comet's head had passed behind the C2 occulting disk.
The second was reported by me on June 15 and by Giuseppe Pappa soon
after, and the third by Bo Zhou on July 3. While neither Bo's (which by my count is his 98th comet) nor my
comet were as bright as Rob's, they both were spectacular objects, and
displayed a tail right up to the C2 occulting disk. Speaking of STEREO,
all three comets were nicely seen in STEREO's cameras as well as SOHO's.
March 7, 2008
The first four STEREO comets (C/2008 D1-D4) were announced in MPEC 2008-E58. The first three to be found were reported by Alan Watson, and the fourth, a fragment of SECCHI-3, by Rainer Kracht..
On Match 5, a day after finding a faint Kracht comet (the first Kracht
in more than two years), Hua Su reported a comet in C3, moving to the
right above the Sun. It turned out to be a non-group comet that
brightened as it made a loop to the upper right of the Sun, entering C2
to the right of the Sun, and cutting across the lower right of the C2
February 22, 2008
After nearly a year of searching by a small but dedicated
group of hunters, the first comet has been discovered in the
STEREO mission's SECCHI HI1A images. Alan Watson , who has been
searching STEREO images from the first, found this Kreutz comet, which
was not detected in the SOHO images. Congrtulations to Alan on the
discovery of SECCHI-1. (Now it looks like he's found a second one!)
I have confirmed with the co-discoverer of Comet Chen-Gao (Tao Chen) that the Xingming Observatory
where the first images of the comet were taken was named in memory of the Chinese comet hunter XingMing Zhou.,
who discovered 63 SOHO comets, 1 SWAN comet, and searched the
night sky for over 1,700 hours for comets. He died in 2004 at the age
of 39 in a driving accident on the way home from an astronomical
SOHO is closed for a couple of days for its roll maneuver. A number of
SOHO comets have been found over the past few weeks, including a bright
Kreutz found by John Sachs, two non-group C2 objects found by Rainer
Kracht, and a Meyer comet that I found.
February 6, 2008
A comet has been found in the night sky by two Chinese
amateur astronomers who also have found SOHO comets. C/2008 C1
(Chen-Gao) was found by Tao Chen on images taken by Xing Gao from
Ximgming Observatory on Mt. Nanshan south of Xing Gao's home city of
Urumqi in Xinjiang province, northwestern China, as part of a nova
survey. The 12th-magnitude comet, now in Cassiopeia, was found in
images from February 1 with a Canon 350D (Digital Rebel XT) DSLR with a
200mm f2.8 lens. Congratulations to Tao Chen and Xing Gao, who become
the fourth and fifth successful SOHO hunters to also find a comet
in the night sky.
January 6, 2008
Happy New Year, everyone! We're still waiting for the
first SOHO comet of 2008 to be found. On December 31, Karl posted some
confirmations (SOHO #1417-1428). Some of the highlights were Parrish
Collison's first comet, Rainer Kracht's 200th SOHO comet (a faint
Marsden comet), one Meyer comet (found by me) and one presumed Meyer
comet (found by Rainer), plus Arkadiusz Kubczak's probable Kreutz
Subgroup II comet (which might be non-group).
Maik Meyer has predicted that, based on average discovery rates,
Meyer-100 will be found around the end of 2009 (if SOHO is still
operational then). He will be announcing a prize for the discoverer of
Meyer-100 after the discovery of the 95th Meyer comet. We are up to 84,
if Rainer's presumed Meyer comet is confirmed as such.
E-mail to tonyhoffman [at] earthlink [dot] net