SOHO/Near-Sun Comet News and Views
2005 News

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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.



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December 31, 2005

Since my last report, ten more SOHO comets have been discovered. The official toll is up to 1079, not including two bright Kracht comets, visible in both C2 and C3, that Rainer Kracht found in archival images from December 1996. (These may be the precursers of several Kracht comets seen in images of September 2002.) Rainer also found two realtime comets, a Kreutz and an obvious Meyer comet in images from December 26. Also on December 26, Steve Farmer, Jr. found a C3 Kreutz comet that got quite bright and was also visible in C2. Karl Battams found two Kreutz comets in C2 images of December 22. Quanzhi Ye found two Kreutz comets, on visible in C3 and C2, the other a faint C2 comet. And Sebastian Hönig found a C2 Kreutz comet.

December 17, 2005

Last night, Steve Farmer, Jr. discovered a non-group C2 comet in images from soon after LASCO came back online after a SOHO roll maneuver, in images of early December 17, UT. The comet tracked from left to right like a star, at a glance it might have been mistaken for one, but it moved faster than the stars and was slightly diffuse. The comet was obvious in C2, fairly steady in brightness until it reached the edge of the C2 field, and also barely visible in C3.

December 14, 2005

I just updated the totals on the Discoverers' Totals page (see the link at top of this page); I'm sorry I haven't been able to update these pages regularly. Karl Battams confirmed eight comets today, to bring the SOHO total to 1070. Among the more interesting comets since my last update were an obvious Kracht comet found by Bo Zhou in delayed realtime images on November 23, seen exiting the C2 field to the right of the Sun, and a bright Marsden comet found by Hua Su, visible in both C2 and C3, on November 29.

November 22, 2005

Today, Karl Battams confirmed 10 comets, bringing the SOHO count up to 1056. These included a very bright Marsden comet, visible in both C2 and C3. This comet, C/2005 W1, may be the return of C/2000 C4. Hua Su also found two faint Meyer comets and a bright Kreutz, plus three more since my last update that Karl confirmed on November 9; these included a C2 non-group that crossed the upper left corner of the field of view. Toni Scarmato also found a Kreutz, visible in both C2 and C3. Quanzhi Ye found his third SOHO comet, a faint C2 Kreutz; I also found a quite faint C2. But perhaps the most memorable objects found were a pair of "twin" Kreutz comets found in C3 that traveled together side by side and were also visible in C3. They were found about 7 minutes apart by 2 Chinese hunters, Wentao Xu and Jiangao Ruan, and it was the first SOHO comet discovery for each of them!

November 4, 2005

Today, Toni Scarmato found a C3 Kreutz comet; it remained fairly faint in C3 but was brighter in C2, and showed a short tail. This should be SOHO comet no. 1042.

November 3, 2005

Tonight, Hua Su found a C2 Kreutz comet. It was faint and quite condensed, stellar in appearance. Hua found C2 Kreutz comets yesterday and on October 30 as well. Yesterday's was faint, with a trace of a tail; the October 30 object was faint, round, and slightly diffuse.

Several other SOHO comets were found since my last update. Rob Matson and Michael Mattiazzo found C/2005 C4 (SWAN) in images from SOHO's SWAN instrument around October 17; it was later confirmed by noted observers Eric Christensen and Rob McNaught in the night sky. See Rob Matson's discovery story by clicking on the Recent News link on the SOHO Sungrazers site. C/2005 C4 (SWAN) is an intrinsically faint comet that reached perihelion on October 9 at 0.65 A.U. from the Sun. It has a period of around 27 years.

The other recent SOHO comets include a C2 Kreutz found by Hua Su on October 19, a C3 Kreutz found by Toni Scarmato on October 21, a Kreutz comet visible in both C2 and C3, found by Bo Zhou on October 23, and a C2 Kreutz found by Quanzhi Ye on October 24; it is Quanzhi's second SOHO comet.

October 18, 2005

Today Hua Su found two C3 Kreutz comets, a faint one early this morning and a brighter one later today. This should bring the SOHO count to 1033.

October 16, 2005

I am sorry that I haven't been able to keep these pages up to date as regularly as in the past. The SOHO comet total has risen to 1031, though Karl Battams has not yet confirmed the most recent two. These were a C2 Kreutz found by Hua Su (the first Kreutz comet discovered in C2 in 3 months) on October 14, and a C3 Kreutz that I found later that evening. It appeared suddenly about 1/4 of the way in from the edge of the C3 field of view, brightened quickly, and followed a Kreutz Subgroup II track clockwise of most of the Kreutz comets found this time of year. It developed a narrow tail that persisted as the comet passed behind the C3 occulting disk, but the C2 disk as well.

The other comets found since my last report include two Kreutz comets discovered by Bo Zhou, both found in C3 and also visible later in C2. The other three were found by Hua Su Two were C3 Kreutz comets also visible in C2; the third was a C2 Meyer comet. The Meyer comet was Hua Su's fiftieth comet, an incredible achievement as it came just 14 months after Hua's first find.

September 28, 2005

Yesterday, Hua Su discovered a C3 comet, visible from the edge of the field. It has become quite bright, and it's still out near the edge of the field. It should be fun to watch for the next couple of days. This is SOHO-1024.

September 27, 2005

It's been a busy week, with 7 new comet discoveries, all Kreutz comets found in C3 that were later visible in C2. Five of them, and nine out of the past 11 comets, were found by Hua Su, bringing Hua's total to 46. Tao Chen also found a comet; this is Tao's second. And congratulations to Quanzhi Ye for finding his first SOHO comet.

September 19, 2005

Today Karl Battams confirmed four comets, his first confirmations in several weeks, bringing SOHO's total to 1016. All four were Kreutz comets found by Hua Su, and they include the two I mentioned in my report from September 7, plus another found on September 15 and another found yesterday. All were visible in C3; the two most recent were also visible in C2. The one found yesterday was particularly interesting. It was moderately bright, with a short tail, and it came from a point about 25 degrees below (clockwise from) where most Kreutz comets approach the Sun; it no doubt was a Kreutz Subgroup II.

In a paper accepted for publication in Astronomy & Astrophysics , Sebastian Hönig links two SOHO comets, C/1999 R1 and C/2003 R5, as apparently being a single comet with an orbital period of 4 years. These comets, along with C/2002 R5 (SOHO), had been presumptive members of a possible new comet group ("Kracht2"). The paper, for which a preprint is available, shows that the latter comet may have separated from the main object in the late 1800s. The return of C/2002 R5 is predicted for next summer, assuming an orbital period similar to that of the main object.

August 30, 2005

On an IAU circular from August 25 or 26 came the announcement of the discovery of C/2005 P3 (SWAN), a comet first detected in SOHO SWAN images by Hirohisa Sato, Masayuki Suzuki, Michael Mattiazzo, Michael Jäger, and Vladimir Bezugly. The first visual confirmation of this magnitude 9.5 comet was by Alan Hale on August 25. This comet can be seen on SWAN images going back to August 4; it quickly climbs out of the solar glare. It is in Ursa Major, and is expected to fade, even as it becomes well placed for observing, becoming circumpolar. By late September, it will be in the bowl of the Big Dipper, and perhaps 12th magnitude. It is uncertain what "SOHO number" this comet will be given, but after several recent finds, it looks like SOHO's total has climbed to 1012.

Yesterday, Hua Su reported a C3 Kreutz comet, still far from the Sun. It turned out that Steve Farmer, Jr. had submitted an earlier e-mail claim, so he will get credit for it. Bo Zhou found another C3 comet today, which trailed Steve's comet; both became moderately bright but were apparently not visible in C2.

Last night (or early this morning, UT), I reported a fairly faint non-Kreutz comet entering C2 as a Marsden comet. On close examination, though, the comet was moving much faster than the average Marsden comet (~100 pixels/hour, compared to about 66 pixels/hour that Rainer Kracht cites for a Marden comet entering C2 in August). Also, its trajectory was a little below the nominal track for a Marsden comet at this date. I soon realized that both of these characteristics--as well as a rapid fading-- were shared by a C2 comet I reported on August 20, 2003; originally thought to be a Marsden comet, its orbital elements make its relationship with the group uncertain; its perihelion distance is considerably less than other Marsdens (.032 AU, compared to a mean of .048 for the group), and its other orbital elements (except inclination) are divergent enough from any Marsdens to make it an anomaly. I wonder, though, if my new comet might not be closely related to it. I look forward to its orbit; unfortunately, it's only visible in 7 or 8 positions.

August 25, 2005

Yesterday, Steve Farmer, Jr. found a C3 Kreutz comet when it was still fairly far from the Sun; it brightened, though it remained fairly condensed in appearance. This morning, Hua Su found a Meyer comet, this one almost hugging the very edge of the C2 field in the upper right corner. It was visible in 7 positions altogether. This should bring the SOHO comet total to 1008.

August 23, 2005

Early this morning (just after midnight, local time), I reported a Meyer comet in C2. Although it was moderately bright (perhaps magnitude 6.5, Karl says), it was difficult to find and to confirm, as C2 was covered with spots of noise ("snow") from a particle storm. It was visible, though, from the image where it entered the field (it cut upwards across the upper right corner) to to the one in which it left, only covered in a single (of 10) image by a cosmic ray hit. This should be Meyer comet no. 60.

August 21, 2005

Early on August 19, Hua Su found a fairly faint non-group comet in C2. I reported it 30 seconds later, and Maik Meyer about 2 minutes after me. The comet emerged from the lower right corner of C2 and headed towards the bottom of the Sun, moving quickly and fading.

August 17, 2005

Today, at last, came the official announcement of the discovery of SOHO-1000; it was the second and fainter C3 Kreutz comet reported by Toni Scarmato on August 5. Congratulations to Toni on finding the two comets in quick succession, with so many other people looking. Here's the NASA press release. \ Karl Battams put up a page on the Sungrazer site about SOHO-1000. The latest SOHO Hot Shot contains an animation of SOHO-999 and SOHO-1000 approaching the Sun, and also congratulations from the SOHO team to all the hunters who have participated in finding its horde of comets. The SOHO operations team, the designers of the spacecraft and especially the LASCO coronagraphs, the professionals who have processed the claims and done the astrometry, and calculated the orbits for these comets, are equally deserving of praise. Finding comets was an afterthought in SOHO's missioon to study the Sun, which was launched nearly 10 years ago, and no one imagined the enormous number of tiny comets, most of them fragments of some of the brightest comets known, while others represent hitherto unknown groups of comets, which before SOHO were forever hidden in the solar glare. The spacecraft has survived far beyond its original two-year operational life, weathering several crises that could have destroyed it. The count is now up to 1004, thanks to a C3 Kreutz comet that Steve Farmer, Jr. found tonight, his second SOHO comet. Let's hope that SOHO will continue to both do its amazing work in studying the Sun and facilitate the finding of sungrazing comets far into the future.

August 15, 2005

Hua Su has found two more C3 Kreutz comets, a relatively faint one yesterday and a slightly brighter one on August 12. This will bring the SOHO comet count to at least 1003. Still no official word on SOHO-1000; I expect a press release, and perhaps an MPEC, will come before Karl posts any more confirmations. I know who found SOHO-1000 for sure now, but I'll leave it to the official announcement to make it public.

August 10, 2005

Tonight I found a Kreutz comet, about halfway across the C3 field; it is small and round and faint. We'll see how it develops. This should be at least SOHO-1001.

Earlier today, Karl Battams confirmed SOHO comets 991-995, with "more to come sometime soon."

Toni Scarmato's brighter comet of August 5 was visible in one C2 image, but must have faded out immediately thereafter, which is common at this time of year for C2 Kreutz comets.

August 5, 2005

Today, Toni Scarmato found two C3 Kreutz comets in delayed realtime images. He reported them about five minutes apart, first a brighter one and then a fainter one preceding it. This should bring the SOHO comet count to at least 1000! Due to several unretracted claims of faint C3 Kreutz comets by veteran SOHO hunters in first few days of August, the identity of SOHO-1000 (and of its discoverer) is still uncertain, but it was most likely one of Toni's two finds today, probably the second. Soon enough, though, Karl Battams will let us know, and there will undoubtedly be a press release forthcoming as well.

It was just a year ago today that the esteemed and masterful SOHO hunter XingMing Zhou died of injuries suffered in a motorcycle accident, and he has been in the thoughts of many of us. Toni dedicated his discoveries to XingMing, and this morning, a number of the Chinese hunters posted a tribute to XingMing on the Yahoo Sohohunter mailing list . "Although he has gone, he will live in our heart forever," they concluded. I am sure that XingMing's example helped inspire the tremendous success of so many Chinese SOHO hunters over the past year.

July 26, 2005

The SOHO comet count has jumped to at least 998, with two comets I found overnight. (I say at least 998 because there is one outstanding claim for a faint Kreutz with reasonable positions, but I can't tell if there's anything there.) Just after midnight, I found a C3 Kreutz, round and fuzzy, nearly halfway from the edge of the field. It was readily visible after a gap due to a defective image. Shortly thereafter, I reported a faint Meyer comet threading its way among spots of noise in the upper right corner of C2. It brightened as it approached the edge of the field. This leaves us no more than two comets shy of SOHO-1000.

In an impressive piece of archival work of the sort he has become reknowned for, Rainer Kracht has found three more SOLWIND comets, two of them Kreutz (which have been announced on IAUC 8573) and one, a non-group, which is still pending. (SMM images are being checked for it as well.) All are about 2nd or 3rd magnitude. Rainer has created a special section of his Web site for SOLWIND discoveries.

July 23, 2005

Tonight I found a faint Kreutz comet about halfway across the C3 field. It was reported by John Sachs just over a minute after me. In the 5 hours since discovery, it has remained a small, faint pointas it advances towards the Sun. This should be SOHO-996. Karl Battams hasn't confirmed any comets since SOHO-990, and if true to his earlier world, won't until the 1000th SOHO comet is found. It is possible that there are other SOHO comets among the outstanding claims, but unlikely as none have been confirmed by other hunters nor look particularly suspicious. So my count is unofficial, and subject to possible revision when Karl Battams finally processes the claims.

After a nice, bright trek across C3, Rob's comet was seen in C2 earlier today in about 9 images. It was bright when it entered C2, but it faded quickly, showing a long, faint (nearly half a degree) tail.

July 21, 2005

Tonight, Rob Matson found what is presumably SOHO's 995th comet, a faint C3 Kreutz that has brightened steadily and has the potential to become relatively bright, as it was still near the edge of the C3 field when discovered. Only 5 more comets to SOHO-1000!

July 14, 2005

Three more Kreutz comets were found in C3 over the past few days, bringing SOHO's total to 994. On July 12, Bo Zhou found a fainter comet trailing Rob's by a few hours; it got obscured by a coronal mass ejection and apparently was never visible in C2. Just after midnight on July 13, Rob Matson reported another C3 Kreutz comet about halfway across the field; this one brightened nicely and was later visible in C2. Later on the 13th, Bo Zhou reported another, this one preceding Rob's by a few hours. It was considerably fainter, though, and was never reported in C2. There were numerous duplicate reports of several of these comets; also, it seems that a lot of newcomers are signing up and have made their first reports. We're just 6 comets away from SOHO-1000 now.

Rainer Kracht has discovered a Kreutz comet in SOLWIND images from November 20, 1981, it was reported on IAUC 8566. The comet was perhaps magnitude 2 or 3, and showed a small tail. SOLWIND was a precursor to SOHO, an orbiting observatory designed to study the Sun and the solar wind. Using a coronagraph, similar to SOHO's yet less sensitive, it detected seven comets between 1979 and 1984; the others were discovered by project scientists. Rainer did his own astrometry, hampered by the absence of visible stars in the field of view. The comet has been designated C/1981 W1 (SOLWIND).

July 11, 2005

Today Rob Matson found the 991st SOHO comet, about halfway across the C3 field en route to the Sun, a small point that is steadily brightening.

The latest SOHO Hot Shot is called "Family Ties Among a Thousand Comets" and discusses the periodicity of Marsden comets, the relationship between the Marsden and Kracht groups and Comet 96P/Machholz, and the Kreutz subgroups.

July 6, 2005

Today, Tao Chen found a faint C2 Kreutz comet, visible in just 5 or 6 images. This is Tao's first SOHO comet, and should be SOHO's 990th.

Karl Battams confirmed comets 985-990 today, from Sebastian Hönig's comet of June 25 to Tao Chen's comet of today. We're just 10 comets away from SOHO-1000 now. Today, NASA issued a press release announcing the approach to SOHO-1000 and saying that it would be found by the end of the summer, though nowhere in the release does it mention how many comets have been find. There is a table with the dates of discovery of milestone comets (SOHO-100, 200, 300, etc.); the last milestone listed, strangely enough, is 897.

June 29, 2005

Today, Kazimieras Cernis reported a C2 Kreutz comet; it was very faint and diffuse. This should be SOHO-989.

June 28, 2005

Yesterday, Rob Matson found two Kreutz comets, a faint C2 comet and a very faint one in C3, which later was obvious in C2 as a round object with a short tail. This should boost the SOHO count to 988.

June 26, 2005

Congratulations to Xavier Leprette , who yesterday became just the third person to reach 100 SOHO comet discoveries, when he found a fairly faint C3 Kreutz comet approaching the Sun from the lower right. It was well seen in C2 as well, round and with a hint of a tail. On June 24, Sebastian Hönig found a small, faint C2 comet. These should bring the SOHO count to 986. The window is closing, though, on the C2 "comet storm" season; virtually no C2-only Kreutz comets are found from July through September. This may slow down the rush to SOHO-1000.

June 20, 2005

On Friday, Karl Battams confirmed both his comet and Xavier's, bringing the SOHO count to 981. Three more comets have been found since then. Yesterday, Hua Su found a non-group comet, cutting across the lower right corner of the C2 field. It was obvious, and elongated in the direction of motion. Tonight I reported a C2 Kreutz comet, which Hua Su reported 24 seconds later. It was clearly visible, round and a little diffuse, with a bit of a tail. Then Jinao Zhang reported a comet in delayed C2 images; it was small, condensed, and moderately bright. It it Jinao's first SOHO comet.

June 17, 2005

An article called "The Booming Science of Sungrazing Comets", co-written by me and Brian Marsden, is the cover story in the August issue of Sky & Telescope. I just got my advance copies today, and one friend has already received a subscriber copy. I'm very pleased at the way it turned out.

June 16, 2005

Karl Battams managed to find one more SOHO comet before LASCO's doors closed. It was a moderately bright, small and round C2 comet, visible after a gap in images. At first he thought it was Xavier's comet entering C2, but that turned out not to be the case. Karl's comet was also visible in C3; this should be SOHO-981.

June 15, 2005

Even as we gear up for the "SOHO-1000 watch", it's now time for the Xavier Leprette watch. Xavier found his 99th comet today (and SOHO's 980th), an obvious C3 comet with a short tail that became visible after a gap in images about halfway across the field of view. Hopefully Xavier will soon become the third SOHO hunter to reach 100.

At around 15:30 UT June 16, LASCO will close its doors in preparation for the SOHO spacecraft being rolled. It will reopen Saturday, June 18, at about 18:00 UT.

June 13, 2005

Three more SOHO Kreutz comets were found in delayed images yesterday. Karl Battams confirmed them today, bringing the count up to 979. Hua Su found what was probably a Subgroup II Kreutz, coming from the lower right corner of the C2 field. It was obvious and diffuse and teardrop-shaped. Then I found a comet that was moderately bright, round, with a trace of a tail, coming from a point about 15 degrees clockwise of Hua Su's. Mine was visible in C3 as well as C2. Later, I found a very faint and small C2 comet. Although it was visible in more than 20 positions, none of the regular SOHO hunters confirmed it before Karl did.

June 11, 2005

Two more SOHO Kreutz comets were found on June, a very faint C2 comet found by Kazimieras Cernis and a faint C3 comet found by Bo Zhou that later appeared as a small, bright spot in C2. Karl Battams confirmed both comets, briging the SOHO total to 976. This was comet number 20 for both Kazimieras and Bo.

An article that I wrote, titled "Discover a Comet Online", has been published in DigitaLife , a special publication of PC Magazine (for which I am employed as a staff editor). The article gives a brief overview of SOHO and sungrazing comets, as well as pointers for newcomers. It is accompanied by an article on hunting for near-Earth asteroids in Spacewatch images for the FMO Project. As far as I know, the magazine is only available on newsstands, and only in the United States.

SOHO has gone into a "keyhole period" ; image coverage will be reduced for the next couple of weeks, and there will be gaps in images. The spacecraft will be flipped in about a week.

June 7, 2005

Karl Battams confirmed four comets today, the three mentioned in the previous report plus a fragment of my C3 comet, which Bo Zhou reported; it was visible in both C2 and (faintly) in C3. The four comets bring SOHO's total to 974; two of them let me reach and pass the 50-comet milestone. Karl gave Sebastian Hönig and me joint credit for the comet that Sebastian found 5 seconds before me; that was my 50th SOHO comet, and Sebastian's 40th. My 51st was the C3 comet of June 5, which brightened very nicely as it approached the Sun; it was visible right up to the occulting disk, and put on a fine show in C2, with Bo Zhou's fragment trailing it to the lower left.

June 5, 2005

It was a busy day for SOHO comets. A fairly faint, round C2 Kreutz comet was visible as new images came in after a gap; Sebastian Hönig reported it first, then I reported it 5 seconds later. Xavier Leprette and Rainer Kracht also reported it within about 2 minutes. Later, I found a Kreutz comet climbing slowly towards the Sun, about halfway across the C3 field of view. Then Hua Su reported a C2 Kreutz comet after a gap in images, in images of June 6 UT.

In the past four days, four new (night-sky, not SOHO) comets discovered by Rob McNaught of the Siding Spring Survey have received official designation. This brings Robs's total to 20, placing him 5th on the all-time list of credited comet discoverers.

June 2, 2005

Two more SOHO comets were recently found; this should bring the SOHO total to 970. On May 31, Karl Battams found a C2 Kreutz comet in delayed images from the previous day. He reported it before the images were released to the public; there was still a problem with the Goddard Space Flight Center image flow. (Just don't do that with SOHO-1000, Karl--unless you want a riot on your hands.) Yesterday, Hua Su found a C2 realtime Kreutz comet, in images with a lot of noise; with the hour's gap between images that persists, it was harder to confirm (though still clearly visible). Karl's was somewhat brighter. These should be Karl's 10th SOHO comet, and Hua Su's 30th SOHO comet. (Hua Su's have all been found in less than 10 months--very impressive.)

May 29, 2005

Yesterday morning, Rainer Kracht found a Meyer comet in C2 images that had been posted the night before. Due to a peculiar image cadence, only one new image ws posted each hour, so it took the comet only about 7 images to cross from above the Sun to the edge of the field. There was a lot of noise in the images, and that coupled with the comet's fast motion made it difficult to detect; I had scanned the same images looking for Meyer comets and had missed it--but it was no problem for Rainer, the reigning comet king.

May 26, 2005

Today Karl Battams confirmed three SOHO comets, bringing the total to 967. One is a small, faint fragment to the left of Hua Su's C2 Kreutz of May 20; the other two are C3 archive comets found by Rainer Kracht; one is from August 16, 2001, the other from September 28-29, 2001.

Today, two MPECS covering a total of nine SOHO comets were released. The circulars, MPEC 2005-K43 and MPEC 2005-K44, cover a Kreutz comet from September 2000 and eight comets from April 2005, six Kreutz, one Meyer, and one non-group.

May 20, 2005

It was a busy week for SOHO comet hunting; with eight new comets confirmed by Karl Battams today. All were C2-only comets, seven Kreutz and one Meyer. John Sachs found a very faint, tailed Kreutz in images of May 14; it appeared as a long, thin streak slightly brighter than the background. Bo Zhou found two Kreutz comets on May 15, one very faint one in delayed images from the previous day, and a obvious (though not bright) one in May 15 images. That evening, I found a small and very faint Kreutz entering C2; I could only make it out in 4 images On May 17, Rainer Kracht found a faint Meyer comet visible in about a dozen images from the previous day. On May 18, Hua Su reported a faint Kreutz with a trace of a tail. Last night, I found a very faint Kreutz with a short tail; there seemed to be a trailing fragment or two condensations, but that was visible only in the first three images. Today, Hua Su found yet another faint Kreutz; there may be a fragment accompanying it, but that has yet to be confirmed.

The spate of new comets brings the SOHO count to 964, which spells the closing of the SOHO 1000th Comet Contest . I chose a date around August 12, but it is looking increasingly like the date will be on the early side; I wouldn’t be surprised if it is in mid-to-late July.

May 15, 2005

On May 10, Bo Zhou discovered two Kreutz comets in C3; one was very stellar in appearance and the other had a bit more of a tail. They both showed up nicely in C2. On May 12, Hua Su found a faint, globular C2 Kreutz comet. Those 3 comets have been confirmed by Karl Battams, bringing SOHO's total to 956. Early on May 14 UT, John Sachs found a very faint and diffuse, tailed Kreutz comet in C2 that appeared as a streak; hopefully Karl will be able to get enough good positions for it to make it official.

May 8, 2005

Three new Kreutz comets were found this week. On May 2, Chong Liang reported a diffuse C2 comet with a bit of a tail. On May 5, Maik Meyer found a very faint and diffuse comet in C2. Tonight, I found an obvious, teardrop-shaped Kreutz comet as it entered C2. It was bright enough to be visible in the first few b/w images as well (unusual for C2 b/w these days because of darkening at the edges of these images); it also proved faintly visible in C3 as well.

Asteroid 2005 HC4, discovered by the LONEOS project on April 30, has a perihelion of only 0.0574 AU, the smallest perihelion distance of any known minor planet. Its orbit is highly eccentric (e = .971).

April 30, 2005

Yesterday, Karl Battams confirmed Rainer's non-group and Bo's Meyer comets, bringing the SOHO tally to 950. Now begins the push to SOHO-1000. After SOHO-960 is confirmed, the SOHO 1000th Comet Contest will be closed to new entries. After SOHO-985, Karl will stop confirming archive claims until after SOHO-1000 is discovered, so as to prevent someone from holding an archive claim in reserve, only to post it after SOHO-999.

April 28, 2005

Tonight, Bo Zhou reported a C2 Meyer comet; it was moderately bright and elongated in the direction of motion.

The Marsden comet that Brian Marsden suspected might return at around this time hasn't been sighted yet, and may well be too faint even if it's survived. Or maybe it will show up tomorrow...

April 26, 2005

Three new comets were confirmed today, bringing the SOHO tally to 948. On April 24, I reported a C2 comet; it was moderately bright, with a short tail. There was speculation that it might be the same as an object reported earlier in C3 by Bo Zhou, but it turned out not to be, as Karl Battams demonstrated. Bo did find a C2 comet today, a small, teardrop-shaped Kreutz. Rainer Kracht found a C2 Kreutz yesterday; it was fairly faint, with a trace of a tail, and came from nearly the bottom of the C2 field; it was probably Subgroup II. Today Rainer reported a non-group C2 comet in yesterday's images; it was round and fairly faint, and traveled to the upper left across the upper right quadrant of the field of view. It has yet to be included in the tally of SOHO comets.

In MPEC 2005-H24, Brian Marsden noted the possibility that Marsden comet C/1999 P6 may be returning within the next few days, assuming that it was part of a fragmentation event that is believed to have occurred around the November 1993 perihelion passage of a Marsden comet whose split presumably created C/1999 N5 and C/1999 J6. He further suggested that C/1999 P8 and P9 may be returning around May 18.

April 22, 2005

Yesterday, Hua Su reported a C3 Kreutz comet; at first, it was up against the pylon and barely visible, but it became clearer and brighter once it cleared the pylon. In C2 it was bright, with a slightly curved tail, and it remained visible for more than 4 hours in that instrument. Chong Liang also reported a Kreutz comet early yesterday, in C2. Karl Battams has confirmed them both; the SOHO comet count is now up to 945.

Rob Matson reported today that Comet 21P/Giacobini-Zinner is faintly visible in SWAN images; Maik Meyer adds that this would make it at least magnitude 10.5 - 11.

April 17, 2005

Today Hua Su reported a Meyer comet in C2. It was readily visible, and slightly elongated. This should be SOHO's 943rd comet, and Hua Su's 25th, all found in an amazing 8-month period.

April 16, 2005

Karl Battams confirmed five comets yesterday, including Bo Zhou's discovery of April 11, mentioned below. The others were a C2 Kreutz and a Marsden comet, both found by Hua Su on April 14. The Marsden comet was in C3, tracking vertically to the left of the Sun. It was then located in C2 images from earlier in the day. The other two comets were archival discoveries by Rainer Kracht (bringing his SOHO total to 150); a Kreutz from September 2000 and a non-group comet from November 10, 2000. Rainer has noted similarities in the trajectories of this non-group comet and C/2001 T5. On the MPEC for the discovery, Brian Marsden notes that the two comets appear to be related, though Maik Meyer cautions that for many of the non-group comets there are several possible orbital solutions, and there's no guarantee that the two are linked.

April 11, 2005

Three C2 Kreutz comets were found in recent days; all were rather condensed in appearance. Hua Su found the faintest of the bunch, in images of April 8. It looked like a small, dim, starlike point as it approached the Sun; it was probably Subgroup II. On April 9, Chong Liang found a somewhat brighter Kreutz; this was Chong's first SOHO comet discovery. Today, Bo Zhou reported a Kreutz, condensed, with a very short tail. Today Karl Battams confirmed the first two of these comets, bringing the SOHO count to 937.

April 6, 2005

I'm sorry there were no updates for a while; I was out of town. On the morning of April 4, Xavier Leprette reported a C3 Kreutz comet in delayed images; it was also visible in C2. It moved below the pylon and presumably belongs to Subgroup II. This should be Xavier's 98th SOHO comet, and the project's 935th. On March 28, three Kreutz comets were found, one each by Maik Meyer, Hua Su, and Bo Zhou. Hua Su's was visible in both C3 and C2, the others just in C2.

March 23, 2005

SOHO completed its roll, and the LASCO doors reopened at 2200 UT this evening. The pylon will interfere with comet discovery in C3 for a few weeks, so most of the Kreutz comets found between now and mid-April are likely to be only visible in C2. Fortunately, a new "comet storm" period in which it will be easier to find C2 Kreutz comets is beginning.

The SOHO comet count is now up to 931, thanks to seven confirmations by Karl Battams over the past two days. Two were of comets found by Hua Su, visible in both C3 and C2, which were found on March 17 and 18, respectively, bringing Hua Su's comet total to 20. The rest of the comets were archive claims e-mailed to Karl; one C3 Kreutz from October 1998 was reported by Xavier Leprette, his 97th comet; four other comets were reported by Rainer Kracht, making him the all-time SOHO comet-hunting leader with 148 finds. His latest include a Kreutz and a non-group from 1997 and a Meyer and Marsden from 1996; all were visible in C3 and the Meyer--from July 3-4, 1996--in C2 also. It is by far the earliest Meyer comet yet reported. The non-group, the Marsden, and a non-group from the last batch have already been MPEC'd.

March 15, 2005

It's been a very busy week, cometwise (especially for March, which is usually a slow period for SOHO comets). Today Karl issued a round of confirmations, bringing SOHO's total to 924. Michael Oates's comet was made official, but thanks to 5 discoveries, including 4 archival C3 Kreutz comets from 1997, Rainer Kracht has drawn into a tie with Mike for the all-time lead with 144 discoveries each. (One of Rainer's archive finds was a non-group comet; there's a small possibility that it could be an already-known comet. The astrometry should let us know for sure.) Rainer's fifth find was a bright Marsden comet from March 10, seen first in C3 and also in C2. Today, Brian Marsden issued MPEC 2005-E87, which suggests that Rainer's comet, C/2005 E4, is identical with C/1999 N5, which came to perihelion on July 11 of that year. He also suggests that C/1999 U2 and the aforementioned comet may have split from each other when near perihelion around Nov. 20-22, 1993, in which case C/1999 U2 should have a period of about 5.95 years and should reach perihelion around this October 8.

Among this week's other discoveries, Hua Su found a C3 comet on March 11, then Bo Zhou reported a C3 comet around March 13 while it was near the very edge of the C3 field. It brightened nicely, and was visible in delayed C2 images from March 14-15 this morning. Bo Zhou also found a faint fragment trailing it. (This brings Bo's total to 10.) On March 14, Xavier Leprette found a faint C2 comet, probably Kreutz Subgroup II (it came from below where most of the Kreutz comets have been entering C2). This is Xavier's 96th SOHO comet. Kazimieras Cernis also reported it in C3, though it was extremely faint and I couldn't really make it out. I did find a C2 comet this morning; it was entering C2 on the 13:36 image (the first after a gap), and when I saw it in the next image I reported it. Xavier then reported a comet in C3 from earlier images, but apparently it was the same as my comet.

March 7, 2005

Yesterday, Michael Oates reported a faint, diffuse, tailed comet in C2, the first Kreutz comet to be found in C2 this year. It was only visible in about 4 positions, so it may be difficult to confirm; Karl is submitting the astrometry to Brian Marsden. A solar storm (CME) hindered its ability to be found in C3.

February 27, 2005

Yesterday, Bo Zhou found two C3 comets. The first was faint; it traveled along the edge of a coronal streamer. The second one, that followed the first by about 12 hours, was found near the very edge of the C3 field. It became rather bright, and showed a straight, thin tail. It was also visible in C2. This brings SOHO's tally to 913.

February 24, 2005

Yesterday, Hua Su found a non-group comet, obvious though not bright, in delayed C2 images. Xing Gao also reported it, less than a minute later. The comet cut upward across the lower right corner of the field. It is SOHO-911; Karl Battams confirmed it and the previous two comets today.

February 22, 2005

Last night, I found a rather faint Kreutz comet, about halfway from the edge of the C3 field from the Sun. The comet grew a short tail and appeared as a small streak in some of the images. This morning, Kazimieras Cernis found another C3 Kreutz comet, slightly brighter than mine and more stellar in appearance. It faded out abruptly. These should be SOHO-909 and 910.

February 13, 2005

Today, Rainer Kracht found a non-group comet in delayed C2 images from February 12-13. The spherical comet brightened as it arced to the upper left across the lower left corner of C2. This is Rainer's 139th SOHO comet.

February 7, 2005

This morning, Xavier Leprette reported a Kreutz comet near the very edge of the C3 field, in delayed images. The comet developed rapidly, becoming teardrop-shaped and quite bright for a SOHO comet. It is now about halfway across the C3 field. This is Xavier's 95th comet, and SOHO's 907th.

February 4, 2005

Karl Battams has now confirmed the four comets mentioned yesterday and given them SOHO numbers. Xavier's archive is SOHO-903, Bo Zhou's and Hua Su's Meyer comets are 904 and 905, respectively, and Hua Su's C3 Kreutz is SOHO-906.

Rainer Kracht's discovery of SOHO-900 is featured in a news note from Sky & Telescope that appeared on the magazine's Web site on February 1.

February 3, 2005

In the past few days, several SOHO comets have been confirmed (though not "in red ink"), bringing SOHO's tally to 906. On January 30, Bo Zhou reported a faint Meyer-group comet in C2 images. On February 2, Hua Su found another faint C2 Meyer comet in delayed images from earlier that day and--less than an hour later--a very faint C3 comet, also in delayed images. Today, Karl Battams confirmed an archival C3 Kreutz comet found by Xavier Leprette in images from March 5, 1997. This is Xavier's 94th SOHO comet find.

January 28, 2005

Karl Battams confirmed two new comets today, bringing SOHO's total up to 602. On January 25, Kazimieras Cernis found an extremely faint Kreutz comet in C3. The next day, Xavier Leprette reported a C3 Kreutz of average brightness, and rather condensed. Kazimieras's comet was so faint that Karl Battams submitted the astrometry before confirming it, just to be sure, so the MPEC with its orbit on it (which also contained an orbit for my non-Kreutz comet of December 28 and two other late-December comets) was released at about the same time that Karl confirmed it.

January 25, 2005

The SOHO-1000 Comet Contest has begun. The object is to predict the perihelion date and time of the 1000th SOHO comet to be discovered; the winner will be the one whose guess is the closest. It will be open until SOHO's comet count reaches 960, still some months away. The first prize will be "a package of goodies that will include the SolarMax DVD, a SOHO T-shirt, solar viewing glasses, and a selection of SOHO materials. Second and third place entries will receive the same package without the DVD." More information, as well as the entry submission form, can be found at the SOHO 1000th Comet Contest page on the SOHO website. Of course, there will be a second, informal contest among SOHO hunters: who will be the one to discover it? Will it be in C2 or C3? Large images or black-and-whites? Kreutz, Meyer, Kracht, Marsden, Kracht2, or non-group? Time will tell.

January 16, 2005

On January 15, Rainer Kracht found a small, faint comet in C3. Congratulations to Rainer; it would seem to be SOHO-900. It is also his 138th comet, putting him just 5 comets away from tying Michael Oates for the all-time SOHO comet lead. On January 13, Hua Su found a C3 comet. It looked small and condensed, stellar, as it approached the Sun.

Comet 2004 V13 (SWAN) survived its passage through LASCO C3 to emergee into the morning sky, though greatly dimmed. David Seargent observed it with a 25cm reflector on January 5, 6, and 7, when he estimated it as magnitude 11.7, 11.6, and 11.9, respectively. Fittingly, it showed up better in a Swan-band filter, indicating that it was still an active comet, producing gas. Michael Mattiazzo, who had been the first to report the comet in SWAN images, also observed the comet on January 6, and created this animation of the comet's motion.

January 9, 2005

On January 6, Hua Su reported a fairly faint C3 Kreutz comet, which was soon after reported by Kazimieras Cernis and David Johnson as well. It remained small, round, and condensed as it approached the Sun.

January 3, 2005

This morning, Yuan-Tseng Tsai found a relatively faint C3 comet. Karl Battams confirmed it, as well as numbering it and other recent discoveries, bringing the total to 897. This includes a comet from October 4, 2004, faintly visible in both C3 and C2, which Hua Su reported on New Year's Day. He also gave a faint Kreutz comet found by Rob Matson on December 28 an X-Comet designation (comet is presumed real but positional data is inadequate to establish an orbit). Karl also recently classified my non-group claim of November 8 and another C3 Kreutz claim from Rob (from December 9) as X-Comets.

January 2, 2005

Early on December 31, I found a C3 Kreutz comet near the edge of the field. New images weren't available for more than a day, and then only in trickles, but they showed the comet brighten significantly and grow a narrow tail of up to 1/3 degree in length as it approached the Sun. It also showed up nicely in C2.

In 2004, a record number of SOHO comets were found. Excluding my latest (which reached perihelion in 2005), 171 comets were discovered, about 142 of which were Kreutz sungrazer fragments. The number of Kreutz fragments has been steadily increasing, from 70 in 1999 to 78 in 2000, 83 in 2001, 106 in 2002, and 128 in 2003 to last year's 142. (These are approximate totals, and include archival comets in their year of perihelion rather than discovery.) See my entry for November 28, and John Bortle's synopsis of Zdenek Sekanina's article on this subject, for more information. Another notable 2004 occurence was the spate of Kracht comets found in May, particularly the 6 found between May 12 and 15. And then, the tentative confirmation of the periodicity of several Kracht and Marsden comets, with periods of 5+ years. Presumably the coming year will see more Marsden/Kracht comets that can be paired with earlier appearances in 1999-2000.




E-mail to tonyhoffman [at] earthlink [dot] net