BAA Comet Section : Comets discovered in 2009

Updated 2013 November 14

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.

Brian Marsden notes on MPEC 2009 O22 [2009 July 21]

It seems rather likely that the two Kracht group comets C/2009 L8 and C/2009 L13 were previously observed as one (or maybe two) of the Kracht members of May 2004 (C/2004 J4, 2004 J12, 2004 J13, 2004 J15, 2004 J16, 2004 J17, 2004 J18 and 2004 J20; see MPEC 2004-M71, 2004-N04, 2004-N05 and 2007-K65). Identity with comets C/2004 A3 or C/2004 B3 (suggested by K. Battams) or with C/2004 L10 (which itself was perhaps a return of comet C/1999 M3) seems a less likely prospect. Given the poor quality of the observations, the computation of a definite linkage is further complicated by the fact that there would have been an approach to within some 1.2 AU of Jupiter in 2008.

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

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.

Brian Marsden published a linked orbit on MPEC 2009-H56 [2009 April 26] and notes:

The above computation, using nongravitational parameters A1 = +0.0002, A2 = -0.0002, is based on work by R. Kracht. Despite the poor quality of the SOHO observations, a purely gravitational computation from the four apparitions appears to leave significantly systematic residuals.

Brian Marsden notes on MPEC 2009-G11 [2009 April 4] that

The "original" and "future" barycentric values of 1/a are +0.024104 and +0.024593 (+/- 0.000001) AU^-1, respectively.

In September, Maik Meyer detected the comet on two SERC-J plates taken in September and October 1994. The two trails appeared slightly diffuse.

Numerous attempts were made to detect cometary appearance in March, but none succeeded [IAUC 9035, 2009 April 7]

The comet was at perihelion in early April at 0.6 AU. At discovery it was visible in the early evening sky, but was too close to the Sun for observation by the end of March. After perihelion UK observers may recover it in June, however by then it will have faded to around 13th magnitude. An early orbit by Hirohisa Sato suggested an ellipse with a period of around 200 years and the latest orbit gives 250 years.

Brian Marsden notes on MPEC 2009-L10 [2009 June 3] that

The "original" and "future" barycentric values of 1/a are +0.025613 and +0.025159 (+/- 0.000007) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-K68 [2009 May 29] that further [astrometric] observations of this comet are desirable.

Brian Marsden notes on MPEC 2009-L11 [2009 June 3] that

The "original" and "future" barycentric values of 1/a are +0.002783 and +0.003054 (+/- 0.000032) AU^-1, respectively.

18 visual and electronic observations received so far suggest a preliminary light curve of m = 5.7 + 5 log d + 5.2 log r

Brian Marsden notes on MPEC 2009-L12 [2009 June 3] that

The "original" and "future" barycentric values of 1/a are -0.000078 and -0.000016 (+/- 0.000101) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-L13 [2009 June 3] that

The "original" and "future" barycentric values of 1/a are +0.012472 and +0.012849 (+/- 0.000041) AU^-1, respectively.

With such a bright object it is surprising that patrol images did not pick it up earlier. One reason is its location in the Milky Way, which is often avoided by the professional search programmes and its orbit is almost exactly along the plane of our galaxy. At least one amateur imager did locate the comet:

Stanislav Korotkiy (Ka-Dar obs., Moscow, Russia) reports that during the patrol photographic survey of the Milky Way he photographed a comet C/2009 F6 on 2009 March 25, 01:26 UT (one day before discovery). He used Canon EOS 20D digital camera + 50-mm f/4 lens. Limiting magnitude was about 13m. During first processing of images no new objects was detected. After a publication of MPEC 2009-G21 that announced an orbit for a new comet C/2009 F6, the images was processed again and a comet was found near the calculated position.

Brian Marsden notes on MPEC 2009-S14 [2009 September 17] that

The "original" and "future" barycentric values of 1/a are +0.001440 and +0.002210 (+/- 0.000016) AU^-1, respectively.

Hirohisa Sato notes that the best fit orbit is slightly elliptical and the latest orbit has a period of nearly 10,000 years.

Brian Marsden notes on MPEC 2009-N14 [2009 July 6] that

The "original" and "future" barycentric values of 1/a are +0.002337 and +0.002432 (+/- 0.000057) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-P11 [2009 August 3] that

The "original" and "future" barycentric values of 1/a are +0.001106 and +0.001305 (+/- 0.000020) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-N15 [2009 July 6] that further [astrometric] observations of this comet are extremely desirable.

Computations by Hirohisa Sato suggest that a long period orbit is also possible and this was confirmed by later orbits.

Brian Marsden notes on MPEC 2009-P12 [2009 August 3] that

The "original" and "future" barycentric values of 1/a are +0.023510 and +0.023929 (+/- 0.000000) AU^-1, respectively.

84 observations received so far suggest a preliminary light curve of m = 7.0 + 5 log d + 0.0172 (T - t - 32)

Observations in ICQ format, last observation 2010 October 18, updated 2010 November 3.

Brian Marsden notes on MPEC 2009-P13 [2009 August 3] that

The "original" and "future" barycentric values of 1/a are +0.000020 and +0.000485 (+/- 0.000039) AU^-1, respectively.

Although it had brightened to around 11th magnitude by early March, observations on March 12 showed a much more diffuse coma than they had on March 5. It has a relatively faint absolute magnitude of 11, so it is possible that the comet is disintegrating, on the other hand the orbit suggests that it has survived previous perihelion passages. The comet has remained at around 11th magnitude into April, but remains diffuse.

Brian Marsden notes on MPEC 2010-G63 [2010 April 9] that

The "original" and "future" barycentric values of 1/a are +0.000348 and +0.004119 (+/- 0.000003) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-S146 [2009 September 30] that

The "original" and "future" barycentric values of 1/a are +0.000080 and -0.000037 (+/- 0.000030) AU^-1, respectively.

Visual observations were reported in 2010 August, with the comet already 13th magnitude. It had reached 8.5 by 2011 July, although the rate of brightening was relatively slow. It reached a first peak of around 7.5 towards the end of August, though some observers continued to record it brightening for another month or two. This perhaps implies that not all observations are independent, and there is a certain amount of “following the trend”. It was widely observed during the first half of 2012, reaching 6th magnitude at its brightest.  It is now poorly placed for observation and fading.

433 observations received so far suggest an aperture corrected preliminary light curve of m = 4.4 + 5 log d + 7.0 log r

Brian Marsden noted on MPEC 2009-S147 [2009 September 30] that

The "original" and "future" barycentric values of 1/a are +0.000446 and +0.000192 (+/- 0.000389) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-R29 [2009 September 9] that

The "original" and "future" barycentric values of 1/a are +0.000021 and +0.000048 (+/- 0.000006) AU^-1, respectively.

Rob Matson found images of the comet on three Heleakala-NEAT images from 1996, which in turn allowed him to find it in two more nights from 1998. It was very bright in the 1996 images showing obvious coma, but barely detectable in 1998.

Reiner Stoss notes the following discovery story on behalf of the LSSS team

Exactly one year ago fellow asteroid hunter Patrick Wiggins posted on MPML his joy about his latest asteroid discovery. You can find the thread in the MPML archive (subject: "It's still possible"). His conclusion was that it is still possible for amateurs to find "bright" asteroids, despite the huge sky coverage by the NASA NEO surveys.

In an attempt to underline this and to motivate other fellow observers I had then posted some experiences made in the first few months of our own sky survey. After just three months of permanently scanning the skies we had received around one thousand designations from MPC and the sky seemed to be full of unidentified asteroids, some of them as bright as magnitude 17.

Now, exactly one year later, the situation has not changed significantly. At J75 we keep scanning with the 45-cm and we find lots of new stuff ranging from magnitude 18 to 20. Sometimes as many as a few hundred possibly new objects per night. It shows that finding new asteroids is not a matter of luck, just a function of search area and limiting magnitude... and more or less the same applies to comets I guess.

We have missed a few of them in the past, either because they were just outside the search area. Or because of some other "constraints" (see below). Now we finally scored one and this one would have gone unnoticed too if MPC wouldn't have linked it to other survey observations so that it showed a cometary orbit and drew special attention therefore. Finding one is way more difficult than finding an asteroid, even a NEO. But I guess it comes too more or less guaranteed after a lot of searching, like with asteroids.

Definitely the times are much harder now compared to the age when Dennis di Cicco wrote his famous "Hunting Asteroids From Your Backyard" article 15 years ago. At that time nearly every mover on the sky was a new one, even at magnitude 16. The big surveys are now in operation since more than 10 years and the number of objects that have been discovered and have received orbits has virtually exploded, from around 29,000 in early January 1996 to more than 460,000 objects now (out of these were 6,800 numbered then vs. 220,000 numbered objects now).

I am not into visual comet hunting, but I think to remember that these folks invested on average hundreds of hours per discovery. Clearly their work was very difficult, learning all those faint galaxies to distinguish them from possible comets without using star maps and a light to not destroy the adaption of the eyes. Today's work is rather different. Being outside with the telescope under the sky was replaced by endless sessions on the computer screen watching CCD images scroll by. Judge yourself what is easier and more pleasurable :o)

I am therefore not able to tell how many hours it took us to score the first one, but here are a few numbers that might help evaluate how much "asteroid work" was done (=sky was scanned) until the first new comet showed up. They are from more or less one year of LSSS operations.

Earlier this month I did extract some numbers for J75 LSSS from the MPC observations database and I noticed that we had meanwhile published more than 500,000 observations for a total of 75,000 individual objects. Thirty percent of all numbered asteroids to date were observed by J75. And the number of designations received from the MPC is now at 3300.

And still, compared to the numbers delivered by Catalina, LINEAR and Spacewatch ours are rather humble. We know that we can't compete with them and it isn't our goal at all. LSSS is working different than the big surveys. It is an amateur survey done entirely remotely. Only one operator is permanently at the observatory, while all others are up to several thousand kilometers away. As all of us have day jobs, it is only possible to run this survey by using every free minute, being connected remotely no matter where we currently are.

My LSSS colleague Jaime Nomen is sometimes working via laptop and 3G card while he is travelling in a high-speed train (AVE) between Barcelona and Madrid. If you ever happen to use that train and you see someone getting anxious when the 3G signal is getting weak in one of the tunnels, you know who it is and what some people do at over 300km/h :o)

Anyway, no matter if you are after asteroids or comets, I think that the closing sentence of Dennis di Cicco's 1996 article is still true:

"There's a lot of stuff out there waiting to be discovered, and it doesn't take long to find it!"

... except with some comets :o)

P.S.: As mentioned above, here is one sure way to lose a comet discovery: Travel to a remote island without taking a 3G card with you! Some of us were on the island of Lastovo in the Adriatic Sea around New Year's Eve 2008/2009, unfortunately without Internet. When we returned on Jan. 2, I checked my email inbox to see the detections made of possibly new asteroids by our telescopes in the past days. I ran them through MPChecker just to find this: ----- The following objects, brighter than V = 23, were found in the 5.0-arcminute region around the following observation:

      8CTB133  C2008 12 30.16450 10 03 12.59 +20 00 29.2          18.3 V      J75
  Object designation         R.A.      Decl.     V       Offsets     Motion/min 
Orbit  Further observations?
                            h  m  s     °  '  "        R.A.   Decl.  Mot.   PA
Comment (Elong/Decl/V at date 1)
     P/2008 Y2 (Gibbs)    10 03 12.6 +20 00 30         0.0W   0.0N    0.6 128.6
cmt  (r =   1.65 AU)

----- We had a comet in the inbox waiting to be reported, right when we were out of town for a couple of days without Internet. And then of course comes what must come... Catalina picks it up, reports it and gets the credit in IAUC 9008 from Jan. 1 Sometimes you lose, sometimes you win :o)

17 observations received so far suggest a preliminary light curve of m = 6.7 + 5 log d + 5.3 log r

Observations in ICQ format, last observation 2010 May 17, updated 2010 ?? [not yet available].

Brian Marsden notes on MPEC 2009-S152 [2009 September 30] that

The "original" and "future" barycentric values of 1/a are +0.000064 and -0.000569 (+/- 0.000035) AU^-1, respectively.

Following publication of the new orbit, Maik Meyer was able to locate images of the comet on Siding Spring images taken on 1995 October 29.

Brian Marsden notes on MPEC 2009-W94 [2009 November 24] that further [astrometric] observations of this comet are desirable.

Following publication of the new orbit, Maik Meyer was able to locate images of the comet on Haleakala-NEAT images taken on 1997 January 15. Due to the mediocre quality of the images a decision on whether the object showed cometary activity was not possible. The magnitude was around 19.

Brian Marsden notes on MPEC 2009-Y10 [2009 December 16] that

The "original" and "future" barycentric values of 1/a are +0.000878 and +0.000942 (+/- 0.000038) AU^-1, respectively.

Reiner Stoss provides the following discovery information

The big surveys didn't miss it. As can be seen in the discovery MPEC and IAUC, Catalina did detect it several times before we did, but it went unnoticed into the huge batch of asteroid ONS data.

MPC then did not link the individual nights because they were not too close together *and* because you can't link them if you assume any realistic "asteroid orbit".

The question could be rather why Catalina missed the cometary nature. I can not answer this question, but I know that it is very easy to miss it. It almost happened to us too this time and for sure many times in the past.

First of all surveys (including us) do not make dozens of images per field to stack them, to see if any object could show a faint coma/tail. They make just relatively short exposures, to maximize sky coverage and to minimize trailing losses for fast-movers. P/2009 T2 did not show a coma or a tail on our survey images from the 45-cm despite the "fast" optics of f/2.8 . It was the pure brightness of this apparently new "asteroid" that made me suspicious, so we quickly scheduled follow-up on our 40-cm tracking telescope. Only those images then showed the tail (already on 90s exposures) and it became more obvious after some stacking.

We pick up sometimes hundreds of new V 19.x movers in one night. We pick up a dozen new V 18.x movers per night and some on the faint end of V 17 too. But it is highly unusual to find a new V 17.0 mainbelt asteroid. The NEOR score was low for what became P/2009 T2 later and its brighness was the only hint that the object could be unsual.

Contrary to what other surveys do (I think most of them check only high NEOR objects visually before posting them to the NEOCP) at LSSS we *do* check each and every new mover visually. "New" means it can't be IDed with the MPCORB. But depending on the quality of the night and several other factors, it is often impossible to tell from survey images if an object is cometary or not, except it shows a big coma and/or a long tail or you are Rob McNaught :o)

I am therefore sure we missed a few comets at LSSS in the past two years or so. They were reported together with thousands of other unidentified asteroidal movers as ONS to the MPC and will get linked eventually as precovery observations to future comets.

Brian Marsden notes on MPEC 2009-Y11 [2009 December 16] that

The "original" and "future" barycentric values of 1/a are +0.000611 and +0.000375 (+/- 0.000076) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-X21 [2009 December 8] that further [astrometric] observations of this comet are extremely desirable.

Brian Marsden notes on MPEC 2009-Y12 [2009 December 16] that

The "original" and "future" barycentric values of 1/a are +0.006289 and +0.005921 (+/- 0.000065) AU^-1, respectively.

Brian Marsden notes on MPEC 2009-Y57 [2009 December 29] that further [astrometric] observations of this comet are desirable.

Brian Marsden notes on MPEC 2009-Y42 [2009 December 22] that

The "original" and "future" barycentric values of 1/a are +0.000042 and -0.000228 (+/- 0.000039) AU^-1, respectively.

Following improved astrometry S. Nakano identified observations of the comet among single-night data from NEAT at the two preceding apparitions in 1997 and 2002, with it being assigned the identifications 1997 A2 and 2002 Q15. Rob Matson independently located the images corresponding to these observations, together with some additional ones and provided measurements. The comet's approach to a distance of 0.88 AU from Jupiter in September 2007 means that the orbital period, currently 6.27 years, was previously 6.48-6.49 years, with the comet's previous two perihelion passages occurring on 2003 Mar. 3 and 1996 Sept. 4.

In April 2010 further observations confirmed that it did have cometary characteristics and the designation was accordingly changed. Perihelion was at 3.9 AU in 2010 December. Gareth Williams notes on MPEC 2010-H68 [2010 April 28]

The orbit indicates an approach to Jupiter within 0.50 AU in 2009 September 24. Before this approach the heliocentric orbit varied between elliptical and hyperbolic. With respect to the solar-system barycenter, the original and future 1/a are +0.00016198 and -0.00143359, respectively.

F. Manca, Bosisio Parini (LC), Italy, has suggested that the comet was observed at its previous perihelion passage as 1999 XO188, the observations of which, all by LINEAR, were given on MPS 9249 and 82876. An orbit was published on MPO 50446. [CBET 2083, 2009 December 17]

Brian Marsden notes on MPEC 2010-B46 [2010 January 27] that

The "original" and "future" barycentric values of 1/a are +0.000427 and +0.000469 (+/- 0.000084) AU^-1, respectively.

The comet was then identified with asteroid 2005 JR71 by Gareth Williams.

9 observations received so far suggest a preliminary light curve of m = 10.1 + 5 log d + 2.7 log r

Brian Marsden notes on MPEC 2010-D88 [2010 February 27] that further [astrometric] observations of this comet are desirable.