BAA Comet Section : Comets in 2000

Updated 2017 September 16

The equations for the light curves of comets that are currently visible use only the raw observations and should give a reasonable prediction for the current brightness. If the comet has not yet been observed or has gone from view a correction for aperture is included, so that telescopic observers should expect the comet to be fainter than given by the equation. The correction is about 0.033 per centimetre. Values for the r parameter given in square brackets [ ] are assumed. The form of the light curve is either the standard m = H0 + 5 log d + K0 log r or the linear brightening m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion, t the present and D0 an offset, if L0 is +ve the comet brightens towards perihelion and if D0 is +ve the comet is brightest prior to perihelion.

Observations of individual comets are given below in ICQ format.

A few observers have spotted the comet in early August, estimating it at around 11th mag. Pepe Manteca imaged the comet on August 10 and August 14. The comet was visible in the SOHO C3 coronagraph, but was fainter than expected and was only 8.8 on September 7.1. It suddenly brightened on September 14 around 15:00 to 6.5.

Observations in ICQ format , last observation 2000 October 4, updated 2000 November 22.

Comet 9P/Tempel 1 is the target for the Deep Impact mission and observations are requested. It will be a very difficult target for amateur observation and may be around 17th magnitude. There were special observing efforts over the weekends of July 8/9, August 5/6 and September 2/3 and from September 26 to October 1.

Observations in ICQ format , no observations, updated 2000 June 1.

Traditionally the light curve is regarded as highly asymmetric with a late turn on. There is a rapid rise in brightness as perihelion approaches, which continues more slowly for a couple more weeks after perihelion, followed by a slow decline until activity switches off. An alternative view is that the light curve is linear with a peak about a month after perihelion, which at this return occurs in early September.

With a 5.5 year period alternate returns are favourable and this was one of them. It was closest to the Earth in July (0.65 AU).

David Strange obtained an image of the comet on July 10. Jose Carvajal estimated it at 10.6 in 32cm L on August 5.9, but I was unable to see it with 20cm R on the same night. On Aug 10.9 Andrew Pearce and I observed it with 14x100B from just outside Penzance, Cornwall, my estimate was 8.7 (HS) and Andrew made it a little fainter. Back in Cambridge it was a very difficult object in the 0.20-m refractor, though it was observed during the IWCA. Andrew Pearce now back in Australia reports that the comet has faded to near 10th mag at the end of August. It is fading very slowly and it was still 12th mag in December.

111 observations received give an uncorrected preliminary light curve of m = 10.4 + 5 log d + 0.0295 abs(t-T-18.1) or 6.1 + 5 log d + 29.3 log r.

Observations in ICQ format , last observation 2000 January 30, updated 2000 August 16.

This annual comet has frequent outbursts and over the past couple of years seems to be more often active than not, though it rarely gets brighter than 12m. It is possible that its pattern of behaviour is changing. In the first half of 1998 it was in outburst on several occasions and this also occurred in 1999. The randomly spaced outbursts may be due to a thermal heat wave propagating into the nucleus and triggering sublimation of CO inside the comet. This comet is an ideal target for those equipped with CCDs and it should be observed at every opportunity.

Jose Aguiar reported as possibly being in outburst on July 1

Observations in ICQ format , last observation 2000 July 1, updated 2000 November 7.

Michael Mattiazzo recovered the comet at 14.0 on July 4.

7 observations received give an uncorrected preliminary light curve of m = 2.1 + 5 log d + 25.9 log r.

Observations in ICQ format , last observation 2000 November 1, updated 2000 November 22.

Observations in ICQ format, last observation 1999 November 30, updated 2000 February 25.

Observations in ICQ format, last observation 2000 February 5, updated 2000 August 16.

It was a difficult object of 14th mag on January 5.

9 observations give an uncorrected preliminary light curve of 5.6 + 5 log d + [25] log r

Observations in ICQ format, last observation 2000 March 5, updated 2000 August 16.

A. Nakamura, Kuma, Ehime, Japan, reports that a CCD image taken low in the morning sky by K. Kadota (Ageo, Saitama, 0.18-m reflector) on Nov. 4.84 UT shows this comet unexpectedly bright at m_1 = 13.2, with coma diameter 0'.5 and a 0'.8 tail in p.a. 310 deg. [IAUC 7518, 2000 November 10]

12 observations give an uncorrected preliminary light curve of 3.8 + 5 log d + [15] log r

Observations in ICQ format, last observation 2000 January 15, updated 2000 January 29.

It reached 14th magnitude last autumn.

Observations in ICQ format, last observation 2000 January 26, updated 2000 August 16.

Observations in ICQ format, last observation 1999 June 12, updated 1999 July 7.

This was its third observed return and it remained at 13th - 14th magnitude from late October into January.

Observations in ICQ format, last observation 2000 February 27, updated 2000 August 16.

29 observations received give an uncorrected preliminary light curve of 9.7 + 5 log d + [25] log r

Observations in ICQ format, last observation 2000 February 27, updated 2000 May 29.

Donald Machholz discovered P/Machholz 2 (1994 P1) with his 0.25-m reflector at 10m in August 1994. It proved to have multiple components, first reported by Michael Jager (Vienna, Austria). The four secondary components could all be described by the same orbit, but with perihelion delayed by up to half a day from the primary. At times there seemed to be a faint trail of material linking the components. The comet has a short period of 5.2 years with a perihelion distance of 0.75 AU and aphelion just inside the orbit of Jupiter. The orbit has been slowly evolving, with progressive changes occurring about every 50 years, thanks to approaches to Jupiter. The most recent close approach was in 1982. With a relatively stable perihelion distance, which is slowly increasing, it is perhaps surprising that the comet was not discovered earlier. There was a favourable return in autumn 1978 when it might have reached 8th magnitude and very favourable returns in the autumns of 1920, 1937 and 1957 when it might have reached 6th magnitude. The fact that it was not discovered at any of these returns suggests either that the orbital evolution is slightly inaccurate, or that the absolute magnitude at the 1994 return was not typical. At present the earth passes about 0.25 AU outside the descending node and the orbital evolution will slowly decrease this distance, raising the possibility of meteor shower from the comet in a few hundred years time.

Robert H. McNaught recovered component A of the comet on CCD images obtained with the 1.0-m f/8 reflector at Siding Spring on 1999 August 3.55.

This return was moderately favourable with the comet moving rapidly eastwards, through Aquarius, Cetus, Eridanus and Orion as it fades. The A component brightened significantly in the last week of 1999 and is now around 10th mag, though it is beginning to fade and become more diffuse. The D component is several magnitudes fainter and is unlikely to be seen. The comet is still several magnitudes fainter than expected. Martin Mobberley imaged the comet on December 29.75. and January 9 . David Strange also imaged it on January 9 . Visually it is a rather diffuse object and I made it 9.7 in my 0.33-m Dobsonian on January 9.74. By mid February it is unlikely to be observable.

42 observations give an uncorrected preliminary light curve of m = 11.7 + 5 log d + 0.0511 abs(t-T-20.6).

Observations in ICQ format , Last observation 2000 February 8, updated 2000 August 16.

Observations in ICQ format, no positive observations, updated 2001 July 24.

Carl Hergenrother provides a story about the recovery:

The naming or not of recovered comets reminds me of a story. Back on 2002 [sic] March 1, Tim Spahr and I were working for the Catalina Sky Survey. He was on the Catalina schmidt surveying for NEOs while I was next door at the Catalina 1.5-m doing my usual comet and asteroid observations.

During the course of the night, Tim would send me interesting objects to observe including a few objects that moved at rates indicative of high eccentricity and hence might be comets. I observed all of them but one which was low in the west. For some reason, we didn't follow it up the next night.

A month later LINEAR finds an object that is linked to a previously designated LINEAR find from March, 2000 ET90. The object is placed on the NEOCP since it has an obvious cometary orbit. Tim noted that the object is one and the same with his suspected comet candidate which I failed to observe.

Feeling bad for Tim and Catalina and for handing LINEAR yet another comet, I tried to find a way to prevent LINEAR from getting this one. I produced an orbit from the published astrometry and the NEOCP ephemeris. A quick search showed 2000 ET90 to be a return of Comet Kowal-Mrkos. Since an announcement had not been made yet, the ID prevented the LINEAR name from being attached to Kowal-Mrkos. So sometimes IDs are made out of spite. :)

Of course, even if I had observed it with the 1.5-m it probably would not have made a difference. There were some big scopes looking at 143P that apparition and no one observed any cometary activity, as far as I know. So I doubt we would have been able to say it was a comet. It's cometary nature was based solely on the orbit at the time.

The case seems similar to that of Chiron, which is (2060) 95P/Chiron, so the object should receive a cometary number. Roll on comet Pluto!

The comet was moved into its present orbit in February 1987 when an encounter to within 0.15 AU of Jupiter made significant changes to the elements.

The comet could potentially have an associated meteor shower. This would be maximum around March 30 and the meteors would appear to radiate from 5h 08m -16.

Observations in ICQ format, last observation 2000 August 27, updated 2000 November 22.

Observations in ICQ format , last observation 2000 September 30, updated 2000 November 22.

The orbit was finally published on MPEC 2000-Q09 [2000 August 19], after Brian Marsden returned to the USA following the IAU meeting in Manchester. It seems that the IAU had commanded all three senior members of the CBAT to attend the meeting. The comet had been at perihelion on July 30.94 at a perihelion distance of 0.054 AU. Potentially observable from the ground it is at an elongation of 50 degrees in late August, though at a magnitude of near 20. The orbit shows that it passed on the far side of the sun, so phase effects do not explain the fading.

Further to IAUC 7472, D. Hammer has provided measurements of a comet detected by the SOHO C2 and C3 instruments and found by J. D. Shanklin via the SOHO website. The reduced measurements and orbits by B. G. Marsden, together with a search ephemeris, are given on MPEC 2000-Q09. G. J. Garradd, Loomberah, N.S.W., reports that his search for this object around Aug. 21.4 UT, out to about 0.5 deg ahead of its predicted position, yielding nothing to mag about 18. [IAUC 7479, 2000 August 21]

     2000 UT           R.A. (2000) Decl.        MPEC
     July 30.221       8 21.5      +19 08       2000-Q09

Observations in ICQ format, no positive observations, updated 2001 July 11.

R. H. McNaught, Siding Spring Observatory, reports observations of a comet found in Sept. 1986 by K. S. Russell on a 90-min exposure taken by F. G. Watson earlier that month with the U.K. Schmidt Telescope. Unsuccessful attempts were made by Russell, and later by McNaught, to locate the comet on the 30-min follow-up exposure by M. Hartley obtained on Sept. 25. T. B. Spahr, Minor Planet Center, has recently identified the comet with 2000 QD_181, an apparently asteroidal object observed by LINEAR on 2000 Aug. 31 and Sept. 5 (cf. MPS 18353), and itself linked by Spahr (MPO 9348) to another LINEAR discovery 2000 XV_43 (observations Nov. 2000-Jan. 2001 on MPS 23109 and 25364), as well as to 1993 WU, recorded by C. S. Shoemaker et al. with the 0.46-m Palomar Schmidt telescope on 1993 Nov. 19 and 20 (MPS 397), the appearance again being evidently asteroidal. With the knowledge of the clearly cometary orbit, McNaught and M. A. Read have now located and measured the object on the Hartley follow-up plate. The 1986 observations were given the designation P/1986 R1. [IAUC 8118, 2003 April 19]

Comet P/2000 QD_181 = 2000 XV_43 = 1986 R1 = 1993 WU (Russell- LINEAR), announced on IAUC 8118, has been given the permanent number 156P (MPC 48317). [IAUC 8128, 2003 May 3]

An encounter with Jupiter in November 2003 makes significant changes to the angular elements and pushes q out to 1.46 AU. Subsequent enounters will further increase q.

Observations in ICQ format , last observation 2000 September 27, updated 2000 November 22.

The IAU Committee on Small Bodies Nomenclature has agreed upon the names for the following five comets: C/2000 S3 (LONEOS); 150P/2000 WT_168 (LONEOS); C/2000 Y2 (Skiff); C/2001 G1 (LONEOS); C/2001 HT_50 (LINEAR-NEAT). [IAUC 7674, 2001 July 30]

The IAU Committee on Small Bodies Nomenclature has given to comet P/2000 S4 (cf. IAUC 7502) the name LINEAR-Spacewatch. [IAUC 7553, 2000 December 31]

82 observations received give an uncorrected preliminary light curve of m = 8.0 + 5 log d + 3.9 log r.

Observations in ICQ format, Last observation 2002 September 12, updated 2002 October 1.

S. Nakano, Sumoto, Japan, reports his identification of comet P/2000 SO_253 (cf. IAUC 7524) with P/1963 W1 = 1963 IX (cf. IAUC 2013), which had been recorded on four Palomar Schmidt plates taken 1963 Nov. 22-25. The resulting orbital elements for the earlier apparition are T = 1963 Oct. 28.5 TT, q = 1.985 AU, i = 4.5 deg, P = 7.89 yr. The comet made approaches of 0.10 and 0.40 AU from Jupiter in 1961 Aug. and 1985 Apr., respectively. [IAUC 7548, 2000 December 23]

This is how the comet was discovered:
On November 18 UT Japanese comet hunter Syogo Utsumoniya saw a possible comet in Vela, very low in his southern sky. Utsunomiya watched the eighth magnitude comet through his 25 x 150 mm binoculars for 40 minutes as dawn approached. During that time the comet moved southeastward about 10 minutes of arc, one third of a full-moon's diameter. Utsunomiya passed the information onto the International Astronomical Union's Central Bureau. They asked a few southern hemisphere observers (none in NZ!) to confirm the discovery. They were unable to locate the comet.

A week later, on Sunday morning Nov. 26 NZ date, Albert Jones of Nelson found the sky had cleared. He got out his 78 mm refractor with the 30x eyepiece and aimed it at the variable star T Apodis. He had intended to observe T Aps two mornings earlier but "ran out of dark sky" before he got to it. Just 50' northwest of the variable Albert saw a hazy spot which he instantly recognised as a comet. He made position and magnitude estimates as dawn came up and phoned them to the University of Canterbury's Mt John Observatory. We immediately emailed Albert's discovery position to the IAU Bureau.

At the Bureau Brian Marsden and Dan Green surmised that the two fast-moving eighth magnitude comets were one and the same object. Brian fitted a parabolic orbit to the two positions and emailed search ephemerides to a few southern hemisphere observers. (The Bureau is very cagey about a suspected comet lest an unscrupulous person 'discovers' it.)

As luck would have it, Mt John had a CCD camera on its 1m telescope. Glen Bayne was taking direct images of Magellanic Cloud eclipsing binary stars as part of his PhD project. (The same CCD is in frequent use on the 1m but attached to a large spectrograph, not available for direct picture taking.) Glen was happy to get pictures of the comet in the twilight.

Using a 15 cm finder 'scope on one of Mt John's other telescopes, Alan Gilmore located the comet in the twilight. This allowed quick setting of the 1m onto the comet and CCD images to be taken. Alan measured these and sent the results off to the IAU Bureau. Three hours later another set of CCD images were obtained by Glen and Alan and the futher positions sent off.

Brian Marsden was then able to fit a semi-accurate orbit to the three nights' observations and show conclusively that the comets seen by Utsunomiya and Jones were indeed the same object. IAU Circular 7526 appeared a few hours later, announcing the discovery and designating the comet 2000 W1. Numerous CCD measurements over the next four days allowed a more accurate orbit to be calculated. This appeared in Minor Planet Electronic Circular 2000-W62 on Nov. 30.

At 80 years old, Albert Jones is the oldest person ever to discover a comet. The next nearest was Lewis Swift who was 79 when he found his last comet in 1899. Albert also holds the record for the longest interval between comet discoveries. His previous comet, also found in a variable star field, was 1946 P1 found in October 1946.

At discovery Comet Utsunomiya-Jones was about 50 million km from earth, hence its rapid movement across the sky. Perspective slows the apparent movement as the comet moves directly away from us and on toward the sun. The angle between the comet and the sun will shrink, causing the comet to sink into the south-west evening twilight. Counterbalancing this, to a greater or lesser degree, is the comet's expected increase in brightness as it nears the sun. So nobody can predict how long the comet will remain visible. It is likely to have disappeared by December 22 when it will be just 19 degrees from the sun.

Comet Utsunomiya-Jones passes closest to the sun on December 26.6 UT. It will remain hidden in the sun's glare till mid January when it will start climbing up the dawn sky. If it behaves like a 'normal' comet then it should have a total magnitude (m1) around nine, visible in medium-sized telescopes.
-- Alan Gilmore & Pam Kilmartin

Albert described his discovery thus:
On the morning of November 26, I was up early (as I do on clear mornings) observing variable stars before dawn, then as I was pointing the telescope to view a faint variable star south of the Southern Cross and Pointers, I noticed a fuzzy object that was new to the region and recognising that it was a comet and not permanent celestial scenery like a nebula, star cluster or galaxy, I noted its position and other details. Then I phoned Alan Gilmore at the Mount John University Observatory (by Lake Tekapo) and told him about it and asked he if he knew about it and its name, but he had no information about it so he e-mailed a message to the International Central Bureau for Astronomical Telegrams (CBAT) at Cambridge, Mass. USA. At breakfast that morning Carolyn wondered why I did not get back to bed before bright daylight - I replied that I had been on the phone to Alan about a comet asking about whether it was a known one. After breakfast a message came from the CBAT saying that it might be the same object that a Japanese comet hunter had seen a week beforehand but which had not been seen again because it was moving south so fast and was thus unconfirmed Using the Japanese positions for the comet and mine, they determined that it was the same object to be known as Comet 2000 W1 Utsunomiya-Jones It has quickly moved towards the west and is moving north again. December 5 was the last evening that I saw it, as it was too low in the sky and behind trees the next night. Next January when the comet's motion brings it into the eastern sky before dawn, it will be much fainter as it races away to the outer reaches of the Solar System. Over 50 years ago, I spent some time looking for unknown comets, and now I find one while pointing the telescope to a variable star ! The moral of the story is to keep looking and you never know what you might see. You just need to be lucky enough to look at the right place at the right time ! By the way, I am told that I am the oldest person to have discovered a comet.

C. W. Hergenrother, Lunar and Planetary Laboratory, reports that this comet has undergone a rapid fading, with R-band photometry showing m_1 about 16.5 for a 1'.7 coma on a co-added 2400-s CCD exposure taken on Feb. 12.6 UT with the Catalina 1.5-m reflector. No nuclear condensation was visible to a limiting mag of 21.0. Earlier visual m_1 estimates: Jan. 17.86, 10.1 (Y. Nagai, Yamanashi, Japan, 0.32-m reflector); 22.88, 10.5 (K. Yoshimoto, Yamaguchi, Japan, 0.25-m reflector); 28.77, 12.0: (M. Mattiazzo, Wallaroo, S. Australia, 0.20-m reflector); 30.28, 11.6 (P. M. Raymundo, northwest of Salvador, Brazil, 0.25-m reflector). [IAUC 7586, 2001 February 22]

Further to the report on IAUC 7586, A. C. Gilmore reports that 3-min unfiltered CCD images taken on Mar. 3.61 UT with the University of Canterbury's Mount John Observatory 1-m f/7.7 telescope showed only a diffuse parabolic glow at the comet's expected position. The glow was brighter and about 1' across at the 'head' end. The 'tail', in p.a. 80 deg, was at least 10' long and widened to about 2' across at the frame's edge. No stellar central condensation was found, though anything brighter than red mag 20 should have been detected. [IAUC 7594, 2001 March 6]

Michael Mattiazzo observed it with 7x50B on November 28.52, estimating it at 7.0, DC4, diameter 5'. It displayed a faint ion tail in 25x100B. I was in the Southern Ocean on board the RRS Ernest Shackleton and made several attempts at observing the comet. These were generally foiled by bright skies or cloud, but I successfully glimpsed it in 10x50B on December 6.09 when it was 6.3 and again the following night.

32 observations received give an uncorrected preliminary light curve of m = 10.8 + 5 log d + 12.7 log r.

Observations in ICQ format, last observation 2001 January 28, updated 2001 May 2.

Brian Marsden notes on MPEC 2001-U43 [2001 October 23], which gives the latest orbit for the comet, that 'The "original" and "future" barycentric values of 1/a are +0.000500 and -0.000266 (+/- 0.000002) AU**-1, respectively.' The original value is greater than 10E-04, hence the comet is probably not a new arrival from the Oort cloud and has made at least one previous visit to the inner solar system.

Schleicher adds that his narrowband photometry of comet C/2000 WM_1, obtained as above on Sept. 18 and 19 (at r = 2.33), yields the following averaged results: log Q(OH) = 27.87; equivalent log Q(water; vectorial) = 27.87; log Af(rho) = 2.42. No temporal or aperture variations were observed. [IAUC 7722, 2001 September 21]

J. Watanabe, National Astronomical Observatory (NAO) of Japan, reports the following antitail lengths and position angles for this comet from I-band CCD images taken by H Fukushima with the NAO 0.50-m f/12 reflector (noting the earth's passage through the orbital plane of the comet on Nov. 20.18 UT): Nov. 16.503, > 8'.5, 283 deg; 17.542, > 6'.5, 300 deg; 18.526, > 7'.9, 302 deg; 19.555, > 6'.2, 317 deg; 22.372, > 4'.7, 1 deg. Small scale jet-like structure near the nucleus was also recognized on these images. [IAUC 7762, 2001 November 29]

Further selected total-visual-magnitude and coma-diameter estimates: Nov. 14.27 UT, 7.2, 12' (C. S. Morris, Fillmore, CA, 10x50 binoculars; 1.1-degree tail); 19.95, 6.3, 18' (R. Haver, Frasso Sabino, Italy, 10x50 binoculars); 22.91, 5.8, 20' (B. H. Granslo, Fjellhamar, Norway, 7x50 binoculars); 30.78, 5.7, 15' (J. J. Gonzalez, Asturias, Spain, 7x50 binoculars); Dec. 3.38, 5.4, 21' (Y. Nagai, Yamanashi, Japan, 7x35 binoculars); 3.79, 5.3, - (Gonzalez). [IAUC 7766, 2001 December 5]

The comet will be visible until August 2002.

I observed it on October 9 under relatively poor conditions, using the Northumberland refractor x230. The comet was surprisingly easy to see and I estimated it at around 12th magnitude. An observation with the Thorrowgood refractor on October 23 put the comet at 10.3, generally diffuse but with a small star-like condensation.

By the end of November 2001 the comet had reached 5th magnitude and was an easy object. It then slowly faded and observations by Southern Hemisphere observers in mid January put the comet at 6th magnitude, about a magnitude fainter than suggested by the preliminary light curve.

Andrew Pearce reports an outburst as follows: 2002 Jan 27.85UT: m1=4.6, Dia=3.5', DC=8...20x80B...Andrew Pearce (Nedlands, Western Australia)[Comet has clearly undergone a significant brightness increase in the last 24 hours or so. Surface brightness of the coma has increased significantly. Faintly visible to the naked eye even at only 10 deg altitude. Tail visible 0.5 deg long in PA 195 deg. Estimate made in 8x40B at the same time: m1=4.6, Dia=4', DC=8. I suspected something may be up the previous morning but the observation was hampered with the comet only 1' away from a 6th mag star. Quick examination of the comet through a 20cm reflector (90x) revealed an intense central condensation which appeared distinctly non stellar. No evidence of any split, however the telescope probably lacked the degree of resolution required to confirm this.]

752 visual observations received give an uncorrected preliminary light curve of m = 7.1 + 5 log d + 10.6 log r which does not take into account the outburst, though the comet is currently close to the indicated magnitude.

Observations in ICQ format, last observation 2002 August 8, updated 2002 October 1.

R. M. Stoss, Starkenburg-Sternwarte, Heppenheim; and R. H. McNaught, Siding Spring Observatory, report the identification with P/2000 WT_168 of two asteroidal trails appearing on U.K. Schmidt plates taken by M. R. S. Hawkins and P. R. Standen on 1978 Mar. 6 and 1986 Mar. 14. Astrometric measurements by McNaught, M. Read, and Stoss appear on MPEC 2001-F17, together with orbital elements by B. G. Marsden from 190 observations spanning 1978-2001 (T = 1978 Jan. 21, 1985 Oct. 22, 1993 July 18, and 2001 Mar. 23). [IAUC 7600, 2001 March 20]

The IAU Committee on Small Bodies Nomenclature has agreed upon the names for the following five comets: C/2000 S3 (LONEOS); 150P/2000 WT_168 (LONEOS); C/2000 Y2 (Skiff); C/2001 G1 (LONEOS); C/2001 HT_50 (LINEAR-NEAT). [IAUC 7674, 2001 July 30]

Observations in ICQ format, last observation 2001 February 17, updated 2002 April 2.

The IAU Committee on Small Bodies Nomenclature has agreed upon the names for the following five comets: C/2000 S3 (LONEOS); 150P/2000 WT_168 (LONEOS); C/2000 Y2 (Skiff); C/2001 G1 (LONEOS); C/2001 HT_50 (LINEAR-NEAT). [IAUC 7674, 2001 July 30]

Additional astrometry, including prediscovery observations by LINEAR on Nov. 29 and Dec. 21 identified by B. G. Marsden, appear on MPEC 2000-Y47, together with the following orbital elements showing this to be a short-period comet. The elements indicate an approach to within 0.05 AU of Jupiter in Sept. 1998. Further to IAUC 7552, J. V. Scotti notes that the comet showed a 7" coma and a 1'.16 tail in p.a. 270 deg on a Spacewatch CCD image taken on Dec. 31.174 UT. An image obtained at Klet on Dec. 30.79 shows a coma diameter of 8" and m_1 = 17.5. [IAUC 7553, 2000 December 31] The comet will fade.

   Comet         2000 UT           R.A. (2000) Decl.
   C/2000 Y6     Dec. 20.454      17 48.7      -23 20
   C/2000 Y7          20.463      17 48.8      -23 19

Observations in early January 2009 showed a coma, and so with observations over two returns and a secure orbit it was numbered 212.