BAA Comet Section : Comets discovered in 2006

Updated 2014 May 1

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 new comets are given in ICQ format. More recent ones may be available in TA format from the main page.

Full details of recently discovered objects will not appear until they are available on the CBAT web pages, which is usually a fortnight after the publication of the IAUC.

Karl Battams has put together a probable family tree for the fragments.

For further information on the discovery of these objects see this year's SOHO discoveries.

In June 2006 the Committee on Small Bodies Nomenclature agreed to name and number the comet, although the asteroidal designation will be used for archiving any astrometry.

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 Committee on Small Bodies Nomenclature has agreed to give the comet P/2000 EC_98 (cf. IAUC 8656, 8660) the same name as the centaur minor planet (60558), Echeclus (cf. MPC 55988), which has been assigned also the permanent comet number 174P (MPC 55911). [IAUC 8677, 2006 February 22]

Observations made since December 2005 appear to indicate that the main source of activity is a secondary body moving independently of the primary, possibly on a hyperbolic orbit. The object was at maximum elongation from the primary around February 25. It may be an escaped satellite or a debris fragment.

Michael Mattiazzo imaged the comet on January 7 and estimated the magnitude as 10.5 in his 20cm reflector. It seems to be brightening quite rapidly as Michael estimated it as 7.9 in 25x100B on January 23.5, with a 3' DC5 coma. I was able to observe the comet on Feb 8.05 from on board the Fishery Protection Vessel MV Sigma at 54S 39W with 10x50B and made it 6.1. For the next three weeks I was at Bird Island, a notoriously cloudy location, but on February 17/18 the skies remained clear and I estimated the comet at 5.6 in 10x50B, DC8 on February 18.21. Observations in late February put the comet at around 5.5. Once in view from the UK, observers reported a 5 degree ion tail in early March. By early April it had faded to around 8.5. Observations by Seiichi Yoshida in early May suggest that further rapid fading occurred as the comet was around 12th magnitude.

Brian Marsden notes on MPEC 2006-E43 [2006 March 11] that

The "original" and "future" barycentric values of 1/a are +0.000798 and +0.000800 (+/- 0.000011) AU^-1, respectively.

107 observations received so far suggest a preliminary light curve of m = 11.2 + 5 log d + 17.9 log r

Observations in ICQ format, last observation 2006 April 4, updated 2006 April 10.

Brian Marsden notes on MPEC 2006-U81 [2006 October 30] that

The "original" and "future" barycentric values of 1/a are +0.000672 and +0.000753 (+/- 0.000014) AU^-1, respectively.

The Committee on Small Bodies Nomenclature has announced that P/2000 C1 = P/2006 A3 (Hergenrother) has been assigned the number 175P (cf. IAUC 8664). [IAUC 8677, 2006 February 22]

Brian Marsden notes on MPEC 2006-G45 [2006 April 13] that

The "original" and "future" barycentric values of 1/a are +0.001020 and +0.001009 (+/- 0.000046) AU^-1, respectively.

The object was recovered in late August, after solar conjunction. It showed no sign of cometary activity and the observations confirmed the 30 year period.

Brian Marsden notes on MPEC 2006-G46 [2006 April 13] that

The "original" and "future" barycentric values of 1/a are +0.004702 and +0.005327 (+/- 0.000038) AU^-1, respectively.

The initial orbit suggested that it would reach perihelion at 1.9 AU in 2007 May, when it might reach 13th magnitude. Further observations however show that it is in a periodic orbit [as first suggested by Hirohisa Sato], period 10 years, with perihelion at 4.1 AU in February 2008. The comet appears to have had a recent close encounter with Jupiter.

Perhaps as expected subsequent observations with a large telescope have revealed a faint coma. Alan Fitzsimmons observing with the 2.0-m Faulkes North telescope on June 4.3 noted a 3" coma. The new orbit is parabolic, but still with perihelion at 2.3 AU in late September.

Brian Marsden notes on MPEC 2006-N10 [2006 July 7] that

The "original" and "future" barycentric values of 1/a are +0.000015 and +0.000058 (+/- 0.000019) AU^-1, respectively.

Subsequent observations have confirmed my suggestion that this was a possible cometary candidate. Observations by S Lowry and Alan Fitzsimmons with the ESO 3.5m NTT telescope and by M Hicks and K Lawrence with the 5m Palomar telescope both show a coma.

The cometary characteristics seem to have been fleeting, and the object reverted to essentially asteroidal nature. Images by Martin Mobberley in December show it at around 14th magnitude.

Further observations changed the preliminary orbit completely and the new estimate is for perihelion at 4.4 AU in July 2007.

Brian Marsden notes on MPEC 2006-P39 [2006 August 11] that

The "original" and "future" barycentric values of 1/a are +0.000016 and +0.001057 (+/- 0.000019) AU^-1, respectively.

Brian Marsden notes on MPEC 2006-S43 [2006 September 22] that

The "original" and "future" barycentric values of 1/a are +0.000005 and -0.000178 (+/- 0.000025) AU^-1, respectively.

Brian Marsden notes on MPEC 2006-Q46 [2006 August 29] that

The "original" and "future" barycentric values of 1/a are +0.000927 and +0.000889 (+/- 0.000050) AU^-1, respectively.

34 observations received so far suggest an uncorrected preliminary light curve of m = 6.7 + 5 log d + 15.8 log r

Observations in ICQ format, last observation 2007 January 20, updated 2007 January 25.

Brian Marsden notes on MPEC 2006-Q47 [2006 August 29] that

The "original" and "future" barycentric values of 1/a are +0.000052 and -0.000057 (+/- 0.000018) AU^-1, respectively.

Brian Marsden notes on MPEC 2006-P16 [2006 August 4] that

The "original" and "future" barycentric values of 1/a are +0.006872 and +0.006441 (+/- 0.000004) AU^-1, respectively.

As is often the case, early magnitude estimates by CCD observers were approximating to m2 rather than the published m1 and by mid July the comet was reported at around 10th magnitude. It was however very diffuse, so much harder to see than the magnitude suggests. It seems to have peaked at around 8th magnitude in August and is now fading.

David Storey recovered the comet from the Isle of Man on September 15. His image showed the comet close to the predicted track, well condensed and about 8th magnitude. Martin McKenna observing from Northern Ireland on September 26 reports a naked eye observation, and a 30' tail in binoculars during a morning observing session. Observing with 20x80B from near Dorchester in Oxfordshire on October 4.80 I noted the comet as 5th magnitude, appearing much like a globular cluster. This appears to have been a short lived outburst as a few nights later it was back to 6th magnitude. A second outburst occurred around October 24, and that evening I was surprised to find it at around mag 4.5 with a short tail. Infra-red observations on November 7, made with the MMT suggest the presence of a secondary condensation, perhaps originating in the October 24 outburst.

Brian Marsden notes on MPEC 2006-S89 [2006 September 29] that

The "original" and "future" barycentric values of 1/a are +0.000106 and +0.000658 (+/- 0.000072) AU^-1, respectively.

43 observations made during November suggest a light curve since the October outburst, corrected for aperture of m = 5.2 + 5 log d + 12.6 log r

Observations in ICQ format, last observation 2006 November 21, updated 2006 November 22.

Following recovery it was numbered 178P.

As suggested above the object eventually grew a coma, which was detected by Carl Hergenrother on CCD frames taken with the 1.54m reflector at Catalina on 2006 September 20.11. The latest orbit is slightly hyperbolic with perihelion at 2.4 AU in 2008 September. It emerged from solar conjunction in 2008 June as a 12th magnitude object and is likely to peak at 10th magnitude in November. It is circumpolar for northern hemisphere observers when brightest during the autumn of 2008 and will remain visible until 2009 May.

CCD observations made it 16th magnitude in 2007 May, and it was around 14th magnitude in August. It was at peak brightness at around 10.5 in 2008 October and is slowly fading.

Brian Marsden notes on MPEC 2007-K71 [2007 May 31] that

The "original" and "future" barycentric values of 1/a are +0.000014 and -0.000672 (+/- 0.000008) AU^-1, respectively.

72 observations received so far suggest a preliminary visual light curve of m = 6.7 + 5 log d + 6.7 log r

It came within visual range in September, with visual observations continuing into November, by which time it had reached 9th magnitude. Twilight images into December suggested that the brightening was continuing.

David Moore reports that he was able to observe the comet from Dublin on the evening of January 1st, estimating it at about 1st magnitude when allowance is made for extinction. Haakon Dahle imaged the comet on January 3 from Fjellhamar, Norway (1s exposure, taken with a Nikon D70 SLR (300mm f/5.6 lens, ISO 800). Nick James imaged the comet on the morning of January 4 from Chelmsford and estimated it at 2.0: from the CCD image. I viewed it on the morning of January 8, estimating it at -1.4, with the comet remaining easily visible until the Sun was 5 degrees below the horizon. Rob McNaught reports a telescopic daylight sighting from Australia on January 9. I attempted daylight observation with the Northumberland and Thorrowgood refractors at Cambridge University Observatory on January 10, but failed to see the comet. It was probably fainter than -3. It was widely observed across the UK on January 10 as shown in my image, with magnitude estimates between -1 and -2. The tail was very prominent. Clouds came in during an observation on January 11, however I provisionally estimated the comet at -2.0:, with a 2 degree tail, although as the sky was brighter it appeared fainter.

Globally, there were many reports of daylight sightings around January 13/14. Richard Miles made daylight photometric measurements of the comet from the UK on January 14, when it was -4.85. It was visible in the SOHO LASCO C3 field from January 12 to 15 and in the STEREO SECCHI HI-1A field from January 11 to 18. From the UK it is no longer visible, although a few observers saw the tail striae around January 18 - 21, before the moon became too bright. The peak brightness of the comet is estimated to have been around -5.5. The enhancement due to forward scatter was around 2 magnitudes, although it seems to be slightly brighter post perihelion than it was before. It is now fading quite quickly, however remains significantly brighter than expected from the pre-perihelion behaviour. There were many reports of daylight sightings around January 13/14. It was visible in the SOHO LASCO C3 field from January 12 to 15 and in the STEREO SECCHI HI-1A field from January 11 to 18. The STEREO images led to the discovery of a neutral iron tail from the comet.

Post perihelion it has shown fantastic tail structure, which is seen in some of the images below.

ESO have observed the comet with the NNT and made observations of sodium in the coma along with spiral jets.

When submitting images please name your image using the format 2006p1_200701dd_name.jpg where dd is the day and name is your name. If you are unsure look at the image names below or see the Comet Image Naming Convention for examples.

Images:

January  3 Haakon Dahle from Fjellhamar, Norway (1s exposure, taken with a Nikon D70 SLR (300mm f/5.6 lens, ISO 800).  
January  4 Nick James from Chelmsford, England
January  5 John O Neill from Rush, Ireland
January  6 Alan Tough from Elgin, Scotland  
January  7 Toni Scarmato from Calabria, Italy
           Vince Tuboly & T Horvath from Hungary
January  8 Nick James
           Martin Mobberley from Cockfield, England  
           Jon Shanklin from Cambridge, England
January  9 Toni Scarmato
           Ian Brantingham from Keith, Scotland
           Derek Ryan from Tarves, Scotland
           Martin McKenna from Maghera, Northern Ireland
           Ken Kennedy from Dundee, Scotland
January 10 Jon Shanklin
           Nick James
           Martin Mobberley
           James Lancashire from Bristol, England
           Arthur Missira from Alston, England
           John Owen from Aberdeen, Scotland
January 11 Jon Shanklin
           Nick James comparison between 10th and 11th
January 14 Richard Miles daylight from Dorset, England
           Russell Cockman from Melbourne, Australia
January 16 Peter Thomas from Darlington, Western Australia
           John Thorpe from Perth, Western Australia
January 19 Rudi Vavra from Lake Illawarra, New South Wales, Australia
           Rolando Ligustri from Avaglio, Italy
January 20 Rudi Vavra from Robertson, NSW, Australia
           Rudi Vavra
           John Thorpe
           Helen Taylor from King Edward Point, South Georgia (54 S)
January 22 Russell Cockman
January 23 Russell Cockman
           Rudi Vavra
           Giovanni Sostero & E Guido from RAS Australia, Melbourne
January 26 Rudi Vavra

161 observations received so far suggest a preliminary light curve of m = 4.4 + 5 log d + 9.4 log r

Observations in ICQ format, last observation 2007 April 15, updated 2007 April 16.

Brian Marsden notes on MPEC 2007-E02 [2007 March 2] that

The "original" and "future" barycentric values of 1/a are +0.000037 and +0.000497 (+/- 0.000003) AU^-1, respectively.

Brian Marsden notes on MPEC 2006-V21 [2006 November 8] that

The "original" and "future" barycentric values of 1/a are -0.000002 and +0.000657 (+/- 0.000048) AU^-1, respectively.

21 observations received so far suggest an uncorrected preliminary light curve of m = 5.5 + 5 log d + 9.0 log r

Donna Burton is being trained as a new observer for the Siding Spring Survey, initially as a replacement for Gordon Garradd who is on 2 months sick leave following a cycling accident. Sep 01 was Donna's first time alone at the telescope. When she found 6R6F4D3 she phoned me so I went to the telescope to check on the detection and show how to schedule follow up. The first follow up was involved with a star, but the next was good. All the data was submitted. It was only with a second call later in the night with her detection of 6R6F50C that I noticed that some of the 6R6F4D3 images looked a bit soft and checking back through the other images confirmed that all images had the same appearance of diffuseness. This was confirmed for certain on images taken the following night. Thus Donna discovered the object and I noted that it was a comet, hence "Siding Spring".

It is still possible that the orbital period P is somewhat longer than the best-fit value of 16 years (which would be the shortest for a comet having a retrograde orbit).

Brian Marsden notes on MPEC 2007-K72 [2007 May 31] that

The "original" and "future" barycentric values of 1/a are +0.000055 and -0.000049 (+/- 0.000009) AU^-1, respectively.

91 observations received so far suggest a preliminary light curve of m = 8.2 + 5 log d + 0.0028 abs(t - T + 323)  

Brian Marsden notes on MPEC 2007-O19 [2007 July 19] that

The "original" and "future" barycentric values of 1/a are -0.000210 and -0.000255 (+/- 0.000244) AU^-1, respectively.

Brian Marsden notes on MPEC 2007-Q05 [2007 August 18] that

The "original" and "future" barycentric values of 1/a are +0.010056 and +0.010546 (+/- 0.000008) AU^-1, respectively.

Calculations by Hirohisa Sato suggested a periodic orbit, and an MPEC was issued on October 7 confirming this. The period is 5.2 years, which perhaps suggests that it was discovered in outburst. Several people, including Cédric Bemer, have suggested the possibility of a meteor shower from the comet around December 31/January 1. The orbit is however still a little uncertain, so it is not clear how much meteoric material is likely to be present. At its next return in 2011 the comet makes a close approach to the Earth. Calculations by Andrew Lowe suggest an approach to 0.024 AU, with the comet perhaps visible to the naked eye. If the comet is fragmenting it may be more likely to have a significant dust trail present.

On MPEC 2006-X54 [2006 December 13] Brian Marsden notes

Further observations of this comet are desirable.

The object was at perihelion at 1.0 AU on October 7. Initial visual and CCD observations suggested that the comet was perhaps a magnitude brighter than the discovery magnitude.

Maik Meyer has suggested a possible link with C/1743 C1. The orbit is rather chaotic, but further observations at the 2011 return may help refine the orbit.

Calculations by Kenji Muraoka suggested that it was a periodic comet, with perihelion at 2.4 AU in late 2006 November and period 7.8 years. Further observations refined the period to 6.6 years, with perihelion at 2.3 AU in mid 2007 January.

Brian Marsden notes on MPEC 2007-P27 [2007 August 10] that

The "original" and "future" barycentric values of 1/a are +0.000542 and +0.000528 (+/- 0.000006) AU^-1, respectively.

An orbit determination by Hirohisa Sato suggests that the orbit may be periodic, with period around 40 years. This was confirmed by a new orbit published on MPEC 2006-W18, and the latest orbit gives perihelion at 4.4 AU in 2007 March.

Brian Marsden notes on MPEC 2006-X07 [2006 December 1] that further [astrometric] observations of this comet are desirable.

Gareth Williams notes on MPEC 2008-P41 [2008 August 8]

   This dynamically-interesting object approached Jupiter to 0.334 +/- 0.001 AU
on 1938 Apr. 14.3 and 0.129 +/- 0.001 AU on 1855 July 31.8 +/- 0.1.  Future
approaches within 1.0 AU of Jupiter occur on 2039 Jan. 22.1 (0.765 AU), 2049
Nov. 11.8 +/- 0.7 (0.911 +/- 0.002 AU), 2056 May 27.8 (0.310 +/- 0.001 AU),
2061 Dec. 12.0 +/- 0.5 (0.521 +/- 0.005 AU) and 2144 Sept. 4.6 +/- 1.0
(0.282 +/- 0.001 AU).

   Heliocentric orbital elements at various epochs, based on the nominal orbit
given above, are as follows:

Epoch           M        Peri.     Node      Incl.       e          a       P
1853/12/13   37.45362   88.01680 147.82346  19.44165 0.0485023  5.1497069 11.69
1857/03/27  284.94642  339.24053 141.52451  18.95632 0.2040891  4.3998660  9.23
1936/08/20  137.93276  340.77339 138.18839  19.10577 0.2004750  4.4222824  9.30
1941/07/25  356.41138  303.56849 133.01257  19.74002 0.1302070  4.9687231 11.08
2008/05/14   94.13335  301.78272 131.79370  20.01894 0.1259691  4.8367248 10.64
2037/05/22    1.61684  301.91593 130.99384  19.96721 0.1244694  4.9129380 10.89
2044/07/04  240.89941  296.13889 126.46441  19.78995 0.1479854  5.0493259 11.35
2052/09/20  167.33962  267.13401 122.89822  19.76945 0.1601488  4.9734302 11.09
2059/04/17   48.69737  229.32296 117.01855  20.14496 0.1081528  5.2125073 11.90
2063/09/03  225.62558  200.15306 113.69874  19.70149 0.1623270  4.8013703 10.52
2142/07/11   78.92772  202.23186 109.70009  19.55345 0.1626978  4.8175254 10.57
2146/05/11  258.76718  174.95910 104.75968  18.15842 0.2101710  4.5661230  9.76

   A plot of the motion of 2006 UG185 over the time period 1900-2100, in a
Jupiter-fixed reference frame, is available at:

       http://www.cfa.harvard.edu/iau/plot/K06UI5G.gif

Also available, for comparison, are plots of the motion of a (588) Achilles
(a routine Jupiter Trojan) and 39P/Oterma (a comet that underwent two close
encounters with Jupiter in the last century):

       http://www.cfa.harvard.edu/iau/plot/00588.gif
       http://www.cfa.harvard.edu/iau/plot/0039P.gif

   Observations with large-aperture telescopes at the forthcoming opposition
are strongly encouraged.

Brian Marsden notes on MPEC 2008-F27 [2008 March 24] that

The "original" and "future" barycentric values of 1/a are +0.004496 and +0.006531 (+/- 0.000002) AU^-1, respectively.

Richard Miles suggestion was confirmed by Carl Hergenrother using the University of Arizona's 1.54-m Kuiper reflector at the Catalina station on December 1st and 2nd. The new orbit is parabolic, with perihelion at 1.02 AU in mid August 2007. The comet came into visual range in 2007 June and reached 8th magnitude in July. The BAA imaged the comet with the Liverpool telescope during the Exhibition Meeting on June 30.

Cédric Bemer notes that the Earth passes 0.005 AU inside the comet orbit on 2008 May 27.1 (solar longitude 66 degrees) and that there may be a possibility of a meteor shower. The radiant is around RA 330 +16. Interestingly Peter Jenniskens lists the gamma Delphinid shower, which has a broadly similar orbit and is active from June 1 - 20 from a radiant around RA 320 +12. Jenniskens gives a possible outburst on 2013 June 11.

84 observations received so far suggest an uncorrected preliminary light curve of m = 8.3 + 5 log d + 11.3 log r

It was a small well condensed object during the northern autumn. I was able to observe it on October 22.8, estimating it at 10.7 in my 0.33-m Dobsonian x45.

228 observations received so far suggest an uncorrected preliminary light curve of m = -0.7 + 5 log d + 14.6 log r.

Following further observations in 2007 September and December, and the publishing of new elements on MPEC 2007-X14 [2007 December 3], S. Foglia, R. Matson, and M. Tombelli identified images of the comet on two UK Schmidt plates from 1993 and 1994. The linked orbit has a period of 16.5 years.

The object was confirmed as a comet in May 2007, when remote observations by Ernesto Guido and Giovani Sostero showed clear evidence of a coma. The comet remains relatively close to the Sun and is poorly placed for observation. It will brighten by a further magnitude to mid May and is best seen from tropical latitudes. The latest orbit gives perihelion at 0.6 AU in late April 2007 and a high eccentricity retrograde orbit.

They provide the following background to there confirmation:

Here is the story. It was clear since its very discovery, that 2006_WD4 was a good candidate to be a comet, since even its preliminary orbital elements were pretty suspicious:

http://www.cfa.harvard.edu/mpec/K06/K06W61.html

Apparently, the object didn't show any significative cometary feature till the end of December, when it was lost in the Sun glare (we now know from CBET nr.952, that some astronomers imaged it with a 2.2m scope under good seeing from Hawaii on Dec.25.4, possibly detecting some traces of a very small coma). We tried its recovery at the end of April, when 2006_WD4 was emerging from the solar conjunction, by means of a robotic scope of the RAS network located near Brisbane. However, due to the bad weather conditions, we could get it only on April 30.8: blinking two series of stacked images, just a few arcmin away from the predicted position, a faint fuzzy "something" was moving with the expected speed and PA. When we performed the co-adding of all the frames we had, a small spiral-like coma emerged (perhaps similar to what is observed frequently on 29P/Schwassmann-Wachmann shortly after one of its outbursts):

http://tinyurl.com/26gzyh

The central condensation appeared pretty sharp (m2 close to 15.3-15.4), surrounded by a faint halo, spanning on average almost 20 arcsec (m1 ~14.2). We wanted to collect a second night of observations, but on May 1 the weather wasn't good enough, so we alerted a few other southern fellow observers asking for some follow-up. Finally we get it again remotely from MPC#E26 on May 2.8; at that time the observing conditions were less favourable compared to a couple of days before (high humidity) anyway an oval coma some 12 x 18 arcsec was detected, with m1 and m2 similar to those found on April 30.8. The preliminary Afrho parameter we derived from our observations, seems to point toward a comet of an overall modest activity (~30 cm), if we consider that we observed it just a few days after perihelion (r~ 0.6 AU). This sounds to be compatible with the fact that it might have "switched-on" effectively only close to the Sun.

We are grateful to H. Sato, M. Mattiazzo and A. Hale, that from time to time reminded us through this mailing-list about the opportunity to perform a check on this interesting target.

We also wanted to thank H. Raab and M. Nicolini for, respectively, their amazing software "Astrometrica" and "Astroart": without their effort, this and most of other cometary confirmation we did would have been simply impossible.

Brian Marsden notes on MPEC 2007-K73 [2007 May 31] that

The "original" and "future" barycentric values of 1/a are +0.002247 and +0.001790 (+/- 0.000002) AU^-1, respectively.

Brian Marsden notes on MPEC 2006-C32 [2007 February] that further [astrometric] observations of this comet are desirable.

Brian Marsden notes on MPEC 2007-E03 [2007 March 2] that

The "original" and "future" barycentric values of 1/a are +0.003833 and +0.004455 (+/- 0.000024) AU^-1, respectively.

Most of the additional observations were located by A. Doppler. The orbit has a Uranus MOID of 0.34 AU, but in the time-frame 1800 to 2100 the closest approach of 2006 XQ51 to Uranus is 6.85 AU in 1979. The closest approach to any of the outer planets during 1800-2100 is an approach to 3.62 AU to Saturn in 1942.

Brian Marsden notes on MPEC 2007-E04 [2007 March 2] that

The "original" and "future" barycentric values of 1/a are +0.000028 and +0.000420 (+/- 0.000018) AU^-1, respectively.