Updated 2022 November 2
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, but if you want to view the latest observations of all comets, here are the ones I've received recently in TA format (note that observations received in ICQ format are in the individual files only). All observation lists are given in ICQ format.
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.
Orbital calculations by Maik Meyer tend to confirm the identity of the object with D/1783 W1. Nakano has computed a linked orbit:
If the comet has made 33 revolutions from 1783 to 2003, this provides a good linkage between D/1783 W1 and P/2003 A1. Because the period of the comet is not certain, the number of revolutions of the comet could be between 37 and 29. Furthermore, in the case of 33 revolutions, the comet made close approaches to Jupiter: on 1923 9 16.0 to 0.35 AU, on 1864 6 1.5 to 0.57 AU, and on 1852 7 3.0 to 0.98 AU with an approach to 0.67 AU on 1793 4 7.5. The closest approach to the earth during this time was at the appearance of 1783.
An apparently asteroidal LINEAR object discovered on January 5.07 with m2 18.4), posted on the NEO Confirmation Page, has been found to be diffuse by CCD observers elsewhere, including at Haleakala (1.2-m reflector, with K. Lawrence reporting the object as slightly diffuse on NEAT images taken on Jan. 7.3 UT, and again somewhat diffuse on Jan. 8.3), at Klet (where M. Tichy found a coma diameter of 8" on images taken on Jan. 8.7 with the 1.06-m KLENOT reflector), and at Ondrejov (where P. Pravec found a faint, small coma that was "marginally apparent", on images taken close to the moon on Jan. 8.8 with the 0.65-m f/3.6 reflector). The object is likely of short period, with the angular orbital elements quite similar to those of D/1783 W1. [IAUC 8044, 2003 January 8]
The name was finally confirmed in 2004 November.
The IAU Committee on Small Bodies Nomenclature has decided to name three comets as follows: C/1996 R3 (Lagerkvist), P/2003 A1 (LINEAR), P/2004 A1 (LONEOS). [IAUC 8430, 2004 November 6]
Observations in ICQ format, last observation 2003 January 15, updated 2003 January 20.
the assumed perihelic parabolic orbit is very tentative. It seems likely that the object is a Centaur, showing cometary activity as (2060) = 95P/Chiron has shown near perihelion.A revised orbit [MPEC 2003-C47, 2003 February 8], including prediscovery observations by Palomar/NEAT (found and measured in NEAT data by Sebastian Hoenig and R Stoss), confirms these general circumstances. The latest orbit [MPEC 2003-G50, 2003 April 9] puts perihelion in 2003 November at 11.4 AU, with the comet currently 11.5 AU from the Sun. The perihelion distance is the largest on record.
Arianna E. Gleason, Lunar and Planetary Laboratory, reports her discovery of a slow-moving comet of 20th mag on Jan. 10.39 UT with the Spacewatch II telescope at Kitt Peak; J. V. Scotti adds that there was a more-or-less symmetrical coma about 20" across. On making follow-up observations on Jan. 11.3 (after placement on The NEO Confirmation Page), D. T. Durig and H. H. Fry (Sewanee, TN, 0.3-m f/5.75 Schmidt-Cassegrain reflector) confirmed a coma 15"-18" in diameter, and F. B. Zoltowski (Edgewood, NM, 0.3-m f/3.3 Schmidt-Cassegrain reflector) noted that the coma/tail structure had the appearance of a broad fan from p.a. 20 deg northward through p.a. 200 deg. On Jan. 12.0, J. Ticha and M. Tichy (Klet Observatory, 1.06-m KLENOT Telescope) indicated a coma diameter of 8"-10", with m_1 = 20.2 and m_2 = 21.0. The object's cometary nature was also noted by T. Gehrels (Spacewatch II) on Jan. 11-13 and by J. G. Ries (McDonald Observatory, 0.76-m reflector) on Jan. 14.3. [IAUC 8049, 2003 January 15]
Brian Marsden notes on MPEC 2003-G49 [2003 April 9] that the "original" and "future" barycentric values of 1/a are +0.000059 and +0.000152 (+/- 0.000016) AU**-1, respectively, suggesting that this is a "new" comet from the Oort cloud. The current orbit is now strongly hyperbolic.
In October 2022 Michael Kelley reported that it showed a tail in ZTF images taken on September 27. Sam Dean then noted that images since at least 2018 showed considerable variation in brightness. It was subsequently designated 2022 B5.
The initial orbit on MPEC 2003-E27 [2003 March 7] was not particularly unusual, apart from a high inclination, however further observations have given a higher eccentricity. Peter Jenniskens has noted a close similarity to the orbit of the Quadrantid meteors. It is worth further study to see if it shows any cometary activity. The orbit is typical of a Jupiter family comet and it can approach within 0.3 AU AU of Jupiter and the Earth. The object is in a 5.53 year orbit, with perihelion at 1.19 AU and an eccentricity of 0.62. It was at perihelion in late February and will fade.
P. Jenniskens, NASA Ames Research Center, has pointed out that 2003 EH_1 (cf. MPEC 2003-E27) would seem to be a very strong candidate for the parent of the Quadrantid meteor stream. The later orbits, from arcs of up to 48 days (MPO 48330), indicate that frequent approaches within 0.2-0.3 AU of Jupiter occur, those during the past century or two evidently increasing q from just under 1 AU (with other orbital elements also very similar to those of the Quadrantids) to the present 1.19 AU. The current theoretical radiant for 2003 EH_1 (R.A. = 229.9 deg, Decl. = +49.6 deg; V_inf = 41.7 km/s at solar longitude 282.94 deg, equinox 2000.0) is at the center of the Quadrantid radiants measured by photographic means, the narrow dispersion implying a young (about 500 years) shower age. From that dispersion, Jenniskens et al. (1997, Astron. Astrophys. 327, 1242) suspected that the parent was still among the meteoroids, hiding as a minor planet. On computing a parabolic orbit for C/1490 Y1, Hasegawa (1979, Publ. Astron. Soc. Japan 31, 257) introduced that comet as the likely Quadrantid parent. In attempting to link the 2003 observations to those of 1490-1491, Jenniskens, and also B. G. Marsden (Center for Astrophysics), have found that most of the potential solutions with the required Jan. 1491 perihelion date yield 0.5 < q < 0.6 AU in 1491, and this is probably too small to fit the data used by Hasegawa. Values in the more acceptable range of 0.7 < q < 0.8 AU (and 0.80 > e > 0.75) certainly arise for 1488 < T < 1494, however, the desired date being clearly attainable with the help also of a close approach to the earth or -- more likely -- the presence of nongravitational forces. Further light could be shed on the problem by the recognition of precovery and/or recovery observations of 2003 EH_1, which is presumably a comet and that should in any case be considered a high-priority object for further study. [IAUC 8252, 2003 December 8]
Additional observations of the object were made at the end of December 2003 and early January 2004 from ESO, La Silla and these, together with a revised orbit appeared on MPEC 2004-N22 [2004 July 5]. Brian Marsden notes
This is the presumed parent of the Quadrantid meteors (cf. IAUC 8252). The recovery observations are still insufficient to shed much light on the suggested identity with comet C/1490 Y1.It is currently a southern hemisphere object and approaching aphelion, so a difficult object to observe at 24th magnitude.
An apparently asteroidal object of 18th magnitude, discovered by the LINEAR project on March 23.43, and posted on the NEO Confirmation Page, has been found to have cometary appearance by numerous CCD observers on Mar. 24-25 (who have reported diffuseness, a coma diameter of up to 10", and a tail of length 7"-40" in p.a. 300-330 deg), including A. R. Apitzsch (Wildberg, Germany); S. Sanchez, R. Stoss, and J. Nomen (Mallorca, Spain); M. Froehlich (Essen, Germany); G. Hug (Eskridge, KS; m_1 = 16.7); J. E. Arlot (Observatoire de Haute Provence); H. Mikuz (Crni Vrh, Slovenia); and L. Buzzi (Varese, Italy; m_1 = 17.7). Available astrometry, very preliminary parabolic orbital elements (q = 3.9 AU, T = 2002 July 31), and an ephemeris appear on MPEC 2003-F35. [IAUC 8098, 2003 March 25]
An apparently asteroidal object of 20th magnitude, found by the NEAT project on March 27.20, and posted on the NEO Confirmation Page, has been reported as faintly cometary by a few observers. G. Masi reports that CCD observations in good conditions (0".9 seeing) with the Danish 1.54-m telescope at the European Southern Observatory on Mar. 28.3 and 29.1 UT show the object to be nonstellar, with a slight elongation toward p.a. 315 deg, such that a nuclear condensation appears on the southeast side of a coma that has size 5".5 along a southeast-northwest axis and 4" along a northeast-southwest axis. Images taken with the 1.06-m KLENOT telescope at Klet on Mar. 31.9 by M. Tichy and M. Kocer show the object as slightly diffuse with a coma diameter of 6". [IAUC 8104, 2003 April 1]
An apparently asteroidal object of 17th magnitude, discovered by LINEAR on April 8.45, and posted on the NEO Confirmation Page, has been found to be cometary by several CCD observers, including L. Sarounova and P. Kusnirak (Ondrejov), A. Galad (Modra), P. Birtwhistle (Great Shefford, U.K.), G. Hug (Eskridge, KS), P. R. Holvorcem (0.81-m Tenagra II telescope; m_1 = 15.4 on Apr. 9.46 UT), and M. Tichy (Klet). The general description of the comet gives a coma of diameter 8"-15" and a straight tail about 40"-90" long in p.a. 210-225 deg during Apr. 9.1-10.0. The available astrometry, preliminary parabolic orbital elements (T = 2003 Feb. 7, q = 4.9 AU, i = 67 deg), and ephemeris appear on MPEC 2003-G56. [IAUC 8115, 2003 April 10]
Brian Marsden notes on MPEC 2003-P15 [2003 August 6] that the "original" and "future" barycentric values of 1/a are +0.000014 and -0.000372 (+/- 0.000005) AU**-1, respectively, suggesting that this is a "new" comet from the Oort cloud.
L. Manguso, Lincoln Laboratory, Massachusetts Institute of Technology, reports the LINEAR discovery of a comet with a 13" coma visible on Apr. 9-10 (discovered on April 8.38 at 18th magnitude). Following posting on the NEO Confirmation Page, the object was also reported to have cometary appearance by G. Hug (Eskridge, KS, 0.3-m reflector; diffuse with m_1 = 16.6 on Apr. 9.4 UT and m_1 = 17.3 on Apr. 10.4) and by A. C. Gilmore and P. M. Kilmartin (Mt. John University Observatory, 0.6-m reflector; diffuse on Apr. 11.6). [IAUC 8116, 2003 April 11]
An apparently asteroidal 17th magnitude object reported by LINEAR on April 24.38, and posted on the NEO Confirmation Page, has been reported to be cometary on Apr. 25 CCD frames taken by H. Mikuz (Crni Vrh, 0.60-m reflector + R filter; strongly condensed with coma diameter about 20" and m_1 = 15.9), P. Kusnirak (Ondrejov, 0.65-m reflector; "seems to be slightly diffuse"), and T. Spahr (Mount Hopkins, 1.2-m reflector; faint fan-shaped tail about 5" long toward the south). [IAUC 8122, 2003 April 25]
Brian Marsden notes on MPEC 2003-P16 [2003 August 6] that the "original" and "future" barycentric values of 1/a are +0.000745 and +0.000450 (+/- 0.000008) AU**-1, respectively, suggesting that this is not a "new" comet from the Oort cloud.
Observations in ICQ format, Last observation 2004 April 17, updated 2004 September 19.
Another apparently asteroidal object of 19th magnitude reported by LINEAR on April 24.40, and posted on the NEO Confirmation Page, has also been reported to be cometary on CCD frames taken on Apr. 25 by Mikuz (diffuse with condensation and coma diameter about 20"), M. Tichy (Klet, 1.06-m reflector; diffuse with faint tail in p.a. 270 deg), and Kusnirak (coma diameter about 10"). [IAUC 8122, 2003 April 25]
Further to IAUC 8122, J. McGaha (Tucson, AZ) reports that six stacked 2-min CCD exposures taken on Apr. 25.3 UT (0.30-m reflector) show a 6" coma and a 10" tail in p.a. 50 deg. [IAUC 8125, 2003 April 30]
Brian Marsden notes on MPEC 2003-P17 [2003 August 6] that the "original" and "future" barycentric values of 1/a are +0.026849 and +0.026146 (+/- 0.000000) AU**-1, respectively, confirming that this is not a "new" comet from the Oort cloud.
S. H. Pravdo, Jet Propulsion Laboratory, reports the NEAT discovery on Haleakala images of a 17th magnitude comet on April 30.45 with a coma diameter of about 14" and an unresolved core of diameter about 4" or less. Following posting on the NEO Confirmation Page, other observers have also reported the cometary appearance from CCD images, including J. E. McGaha (0.30-m reflector, Tucson, AZ; fainter outer coma of diameter about 10" with a brighter core of diameter about 5"); J. Young (0.6-m reflector, Table Mountain; coma diameter about 8", and 16" tail in p.a. 250 deg, affected by cirrus clouds), and P. R. Holvorcem and M. Schwartz (Tenagra IV 0.36-m telescope, near Nogales, AZ; coma diameter 28" and m_1 = 15.4-15.7 on May 1.47). [IAUC 8126, 2003 May 1]
Brian Marsden notes on MPEC 2003-P18 [2003 August 6] that the "original" and "future" barycentric values of 1/a are +0.000438 and -0.000114 (+/- 0.000005) AU**-1, respectively, suggesting that this is not a "new" comet from the Oort cloud.
M. Bezpalko, Lincoln Laboratory, Massachusetts Institute of Technology, reports the discovery by LINEAR of a comet with a tail in p.a. 270 deg on images taken on Apr. 29.3 UT. Following posting on the NEO Confirmation Page, other CCD observers have also reported the object as cometary, including G. J. Garradd (Tamworth, N.S.W., 0.45-m reflector; slightly diffuse on most images taken on Apr. 30.6), J. E. McGaha (Tucson, AZ, 0.30-m reflector; faint coma of size 5" x 10" and m_1 = 17.7-17.9, aligned north-south, with uniform brightness and no apparent nuclear condensation or core on May 2.2), and J. G. Ries (McDonald Observatory, 0.76-m reflector; 20" tail pointing slightly south of west on May 2.3; m_1 = 17.7-18.0). [IAUC 8127, 2003 May 1]
Orbital elements on MPEC 2003-K34, indicate that this comet passed 0.07 AU from Jupiter in June 1929, before which q and P were larger. [IAUC 8135, 2003 May 24]
An apparently asteroidal object reported by LINEAR (discovery observation published on MPS 78496; prediscovery LINEAR observations published on MPS 80247; orbital elements on MPO 48372) has been found cometary by C. Hergenrother, who reports a diffuse coma of diameter 15" (and mag 18.6 within an aperture of radius 8") and a broad tail 60" long in p.a. 115 deg on co-added 900-s R-band images taken on June 24.3 UT with the Mount Hopkins 1.2-m reflector. [IAUC 8156, 2003 June 25]
K. J. Lawrence, Jet Propulsion Laboratory, reports the discovery by NEAT of a comet on May 13.59. Following posting on the NEO Confirmation Page, other CCD observers reported the following total magnitudes and coma diameters: May 14.5 UT, m_1 = 16.4-17.0, 10" (P. Holvorcem, Tenagra II 0.81-m telescope; three co-added 120-s exposures); 15.5, 17.5, 8" (J. Young, Table Mountain, CA, 0.6-m reflector). [IAUC 8133, 2003 May 17]
Brian Marsden notes on MPEC 2003-O37 [2003 July 30] that the "original" and "future" barycentric values of 1/a are +0.001841 and +0.001804 (+/- 0.000077) AU**-1, respectively, suggesting that this is not a "new" comet from the Oort cloud.
It was refound as 2008 JL14, also at Kitt Peak. The linked orbit has a period of 5.0 years, with perihelion at 1.28 AU. The earth MOID is 0.46 AU. [MPEC 2008-O29, 2008 July 26]
An object of 20th magnitude initially reported as asteroidal by J. A. Larsen on CCD images obtained with the 0.9-m Spacewatch reflector on May 23.38 was posted on the NEO Confirmation Page. CCD images taken by A. Lopez and R. Pacheco (Mallorca, 0.41-m reflector) on May 23.9 UT showed cometary appearance (and m_1 = 18.2-18.6). A. E. Gleason found the coma to be quite obvious on May 24.3 images taken with the 1.8-m Spacewatch II reflector at Kitt Peak, and Larsen found a 10" coma on Spacewatch I images taken on May 24.4. [IAUC 8135, 2003 May 24]
Eric Christensen, Lunar and Planetary Laboratory, reports the discovery of a 15th magnitude comet on May 26.18 by the Catalina Sky Survey on CCD images taken with the 0.7-m Schmidt telescope. Following posting on the NEO Confirmation Page, many observers noted the obvious cometary nature of the object on CCD images taken during May 27.1-27.2 UT, including R. Elliot (Fall Creek, WI; coma diameter about 10"), P. R. Holvorcem and M. Schwartz (near Nogales, AZ; coma diameter about 35", with a 30" tail in p.a. 106 deg), J. Young (Table Mountain, CA; 10" coma and a very faint 40" tail in p.a. 115 deg with a slight curve halfway along its length to p.a. 130 deg), and J. McGaha (Tucson, AZ; coma diameter 12", with slight nuclear condensation and a 6" tail). [IAUC 8136, 2003 May 27]
It has been noted by numerous individuals that the preliminary orbital elements of comet C/2003 K2 (cf. IAUC 8136) place it close to the position of an unconfirmed object found on SWAN ultraviolet SOHO website images and reported to the Central Bureau on Apr. 14 by X.-m. Zhou (Bo-le, Xin-jiang, China). Measurements of the object on six dates, Apr. 5-19, were forwarded to the Central Bureau by Zhou (via D. H. Chen), by M. Mattiazzo, and by S. Hoenig; the positions differed considerably, due to the poor resolution of SWAN (uncertainty on the order of 1 degree). Two search ephemerides based on various positions were circulated by the Bureau to numerous visual and CCD observers in the hopes of optical confirmation, but the searches (undertaken during the last week of April by Zhou, A. Hale, Mattiazzo, Y. Kushida, and Y. Ezaki) revealed nothing to as faint as mag 14.5. The following improved parabolic orbital elements for C/2003 K2 (from MPEC 2003-K49) indicate that the search-ephemeris positions in late April for the SWAN object were no closer than about 2.5 degrees from C/2003 K2. The comet might be of short period. [IAUC 8138, 2003 May 30]
By early August 2003 it had brightened to 16th magnitude (CCD). The first visual observations were made in February 2004. Initially it only brightened slowly and reached 10th magnitude at the end of May. During June it has brightened quite rapidly and reached 8th magnitude mid month and was approaching 7th magnitude by the end of the month. It has passed its most northerly declination and is now heading south. On July 15 Juan José González observing from Leon in Spain reported glimpsing the comet with the naked eye. During the rest of July and up to mid August there was little change in brightness, with the comet remaining at around 6.5. As it got lower in northern skies it become harder to observe, however I managed to make a final observation of it on September 1.9, estimating it at around 6.5.
It passed through the SOHO LASCO fields as a 7m object from 2004 September 27 to 2004 October 13, rather fainter than was expected. Alexandre Amorim recovered it at 7.3 in 20x80B on October 26.11. Andrew Pearce reports detecting an anti-tail on November 13.80, when the comet was 7.2 in 20x80B. The orbital plane crossing was on October 11.7 according to calculations by Akimasa Nakamura. The comet remained fainter than expected, but fading only very slowly until 2005 January, when it seemed to resume fading on the previous light curve.
An apparently asteroidal object found by the LINEAR survey on May 28.38, posted on the NEO Confirmation Page, has been found to show a round coma of diameter 5"-7" (m_1 = 17.5) on CCD images taken by J. Young on May 29.5 and 30.4 UT with the 0.6-m reflector at Table Mountain. J. McGaha, Tucson, AZ, reports that three stacked, 2-min CCD images, taken on May 29.4 with a 0.30-m reflector, show a 3" nuclear condensation and a 6" coma that is offset to the northeast. [IAUC 8139, 2003 May 30]
Further to IAUC 8358, R. W. Russell, D. L. Kim, M. L. Sitko, and W. J. Carpenter report 3-13-micron spectrophotometry of comet C/2003 K4, obtained on June 20.3 UT at Mt. Lemmon (integration times 90 min on the comet; reference star alpha Boo): "A continuum, smooth to within the signal-to-noise, was seen to rise from 3.5 to 8 microns, beyond which a weak silicate emission band may have been observed. An underlying blackbody continuum with a temperature of about 235 +/- 10 K was fit to the continuum fluxes at 8.4 and 12 microns. This grain temperature is about 22 +/- 5 percent higher than that of an equilibrium blackbody at the comet's heliocentric distance. Using the same wavelength region (10.34-10.71 microns) as for other, brighter comets in order to calculate a silicate- feature-to-continuum ratio, the possible silicate feature was about 1.10 +/- 0.05 times higher than the continuum, with the silicate- feature-to-continuum ratio > 1. The comet showed the following narrowband (about 0.25 micron) magnitudes and combined random errors: [8.0 microns] = 4.25 +/- 0.10; [10.5 microns] = 2.41 +/- 0.06; [12 microns] = 1.76 +/- 0.06. Due to the low flux level of the comet and the weakness of its silicate feature, no structure due to crystalline material was discernible." [IAUC 8361, 2004 June 24]
C. E. Woodward and M. S. Kelley, University of Minnesota; and D. H. Wooden, Ames Research Center, NASA, report 8-13-micron spectrophotometry of comets 2001 Q4 and 2003 K4 using the NASA Ames HIFOGS spectrometer at the Infrared Telescope Facility 3-m reflector: "Weak silicate-feature emission (cf. IAUC 8360, 8339) is present in the 10-micron spectra of C/2001 Q4 on July 28.24 UT, when the observed N-band magnitude (3" circular aperture) was 3.7 +/- 0.4. Preliminary analysis of the featureless 10-micron spectra of C/2003 K4 suggests that large amorphous carbon and silicate grains (radius approximately > 0.7 micron) dominate the coma. Further to IAUC 8361, no structure attributable to crystalline silicates was evident. The observed N-band magnitudes (3" circular aperture) of C/2003 K4 were: July 26.24, 3.6 +/- 0.4; 27.24, 3.4 +/- 0.2." [IAUC 8378, 2004 August 3]
M. L. Sitko, University of Cincinnati; R. W. Russell, D. K. Lynch, and D. L. Kim, Aerospace Corporation; and R. B. Perry, Langley Research Center, NASA, report on further infrared spectrophotometry of comet C/2003 K4 (cf. IAUC 8361, 8378), obtained on Aug. 5.3 and 6.3 UT using the Aerospace Corporation's BASS spectrograph at the Infrared Telescope Facility 3-m reflector. A smooth continuum was seen between 8 and 13 microns, with a possible weak silicate emission band superimposed. Underlying blackbodies with temperatures of 250 +/- 5 K and 245 +/- 5 K were fitted to the continuum fluxes at 8.4 and 12 microns on Aug. 5 and 6, respectively. These grain temperatures are about 8-10 percent higher than that of an equilibrium blackbody at the comet's heliocentric distance. Using the 10.2-10.7-microns region to calculate a silicate feature-to-continuum ratio, this ratio was 1.09 +/- 0.03 on Aug. 5, and 1.03 +/- 0.03 on Aug. 6. On Aug. 5, a weak feature due to crystalline olivine may have been present at 11.2 microns. Scattered solar radiation was evident at wavelengths shorter than 4 microns. The observed magnitudes determined between 10.2 and 10.7 microns, using the instrument's 3".4 aperture and 18" nod, were 2.8 and 2.7 on Aug. 5 and 6, respectively (+/- 0.03 mag, the errors being dominated by the presence of variable sky transparency during the observations). [IAUC 8391, 2004 August 18]
Brian Marsden notes on MPEC 2003-R44 [2003 September 9] that the "original" and "future" barycentric values of 1/a are +0.000020 and -0.000199 (+/- 0.000014) AU**-1, respectively, suggesting that this is a "new" comet from the Oort cloud.
550 observations received so far give a preliminary light curve of m = 4.0 + 5 log d + 11.1 log r, though this does not fit the observations made close to conjunction very well.
Observations in ICQ format, Last observation 2005 February 15, updated 2005 March 1.
Another apparently asteroidal LINEAR object found on May 23.16, announced on MPEC 2003-K27 as 2003 KV_2 (see also MPEC 2003-K38 and 2003-K47), has been found cometary on R-band images taken by C. Brinkworth and M. Burleigh on May 28.9 and 29.9 UT with the 1-m Jacobus Kapteyn Telescope on La Palma (communicated by A. Fitzsimmons), in which the object shows a tail about 4"-5" long in p.a. 125 deg and a small coma that is somewhat larger than the surrounding field stars. The preliminary orbit shows a passage 0.55 AU from Jupiter in Jan. 2001, before which the perihelion distance was somewhat larger. [IAUC 8139, 2003 May 30]
Observations in ICQ format, No positive observations, updated 2003 October 25.
J. V. Scotti, Lunar and Planetary Laboratory, University of Arizona, reports the discovery of a 20th mag comet on CCD images taken with the Spacewatch 0.9-m f/3 reflector at Kitt Peak on June 4.21, showing a coma of diameter 6" and a faint tail about 0'.62 long in p.a. 273 deg. Images taken by A. S. Descour on June 5.3 UT with the 1.8-m f/2.7 Spacewatch reflector also show a tail, and June 7.2 images by Scotti with the larger instrument show the tail 0'.30 long in p.a. 273 deg. [IAUC 8145, 2003 June 7]
Clearly diffuse NEAT images of this comet, taken with the Palomar 1.2-m Schmidt telescope on three nights in 2002 April, were identified and measured by M. Meyer. Additional astrometry and the following orbital elements (MPEC 2003-M21) confirm the suspicion (cf. IAUC 8145) that this is a short-period comet. [IAUC 8153, 2003 June 19]
An apparently asteroidal object found by LINEAR, and posted on the NEO Confirmation Page, has been found to be cometary on CCD images taken by S. Sanchez, R. Stoss, and J. Nomen (Mallorca, 0.30-m f/9 reflector; 10" coma on June 12.95 UT) and by S. Gajdos (Modra, 0.6-m f/5.5 reflector; diffuse with coma diameter about 5" on June 13.97; m_1 = 18.0). [IAUC 8151, 2003 June 14]
Brian Marsden notes on MPEC 2003-R45 [2003 September 9] that the "original" and "future" barycentric values of 1/a are +0.006356 and +0.006809 (+/- 0.000011) AU**-1, respectively, and the eccentricity is 0.9814155 showing that this is not a "new" comet from the Oort cloud.
An apparently asteroidal object reported by LINEAR, and posted on the NEO Confirmation Page, has been found to have cometary appearance on CCD images taken by P. Kusnirak (Ondrejov; 0.65-m f/3.6 reflector; well-condensed condensation and a faint 20" tail toward the southeast) and by P. Birtwhistle (Great Shefford, U.K.; nuclear condensation of diameter about 6" with a faint, short, broad tail about 15" long in p.a. 139 deg; mag 17.3-18.2). [IAUC 8170, 2003 July 30]
Brian Marsden notes on MPEC 2003-R09 [2003 September 2] that the "original" and "future" barycentric values of 1/a are +0.000225 and +0.000217 (+/- 0.000018) AU**-1, respectively, suggesting that this is probably not a "new" comet from the Oort cloud.
Further observations confirm the short period nature of the orbit, with perihelion at 1.5 AU in early September and a period of 8.8 years. It will not get much brighter than at present.
M. Bezpalko, Lincoln Laboratory, reports the LINEAR discovery of a comet, showing a tail approximately 42" long in p.a. 230 deg. Other CCD observers report mag 16.9-17.9 and a tail of up to 6' long in p.a. 245-250 deg on July 30-31 (including S. Sanchez, R. Stoss, and J. Nomen at Mallorca; R. Trentman and R. Frederick at Louisburg, KS; and P. Birtwhistle at Great Shefford, U.K., who also noted a 9" central condensation of mag 17.9, adding that the tail was very diffuse and wide). [IAUC 8172, 2003 July 31]
An apparently asteroidal object reported by LINEAR, and posted on the NEO Confirmation Page, has been found to be apparently cometary on CCD images taken by P. Birtwhistle (Great Shefford, U.K., 0.30-m reflector; very faint tail about 10" long in p.a. approximately 270-280 deg on July 31.10 and Aug. 2.08 UT; mag 18.1 and coma diameter about 5" on Aug. 2.08), by J. Ticha and M. Tichy (Klet, 1.06-m KLENOT telescope; diffuse with a wide tail in p.a. 260 deg on Aug. 3.01), and by J. McGaha (near Tucson, AZ; possible tail spike 5" long in p.a. 300 deg on Aug. 3.38 with a 0.30-m reflector; possible fan-shaped tail 5" long in p.a. 260 deg on Aug. 5.33 with a 0.62-m reflector). The preliminary orbital elements indicate that the comet passed 0.3 AU from Jupiter in Nov. 1979. [IAUC 8174, 2003 August 5]
An apparently asteroidal object reported by NEAT (Palomar discovery observation originally posted on the NEO Confirmation Page, then assigned the designation 2003 QX_29 on MPEC 2003-Q33; observations on MPS 93475-93476) has been found to have cometary appearance on CCD images taken by I. Griffin and S. G. Huerta (Cerro Tololo 0.9-m reflector, Aug. 31.1 UT; visible coma of red mag 18.0-19.4 with FHWM = 2".3-2".6 in raw 300-s images, while stacked 10-exposure image shows a fan-shaped tail at least 17" long in p.a. 58 deg) and by J. Young (Table Mountain 0.6-m reflector, Sept. 1.2; 3" coma, slightly elongated in p.a. 260 deg, with a 16" curved tail starting in p.a. 243 deg; possible slight brightening in the tail at a point 4"-5" from the coma edge). J. Ticha subsequently reports that Klet images from Aug. 23.9 show the object to be slightly diffuse, while on Aug. 24.9 it exhibited a 8" coma. Astrometry, orbital elements (T = 2002 Oct. 17.3 TT, Peri. = 37.1 deg, Node = 264.9 deg, i = 11.4 deg, equinox 2000.0, e = 0.445, q = 4.311 AU, P = 21.6 yr), and an ephemeris appear on MPEC 2003-R14. [IAUC 8192, 2003 September 2]
An apparently asteroidal object reported by LINEAR, and posted on the NEO Confirmation Page, has been reported to have cometary appearance on CCD images obtained by J. Ticha and M. Tichy (Klet, 1.06-m KLENOT telescope; slightly diffuse object with a 6" coma on Sept. 5.08 UT, and asymmetric coma to the northwest on Sept. 6.05); and by J. E. McGaha (Tucson, AZ, 0.30-m f/10.0 Schmidt-Cassegrain reflector; 3" coma with a fan- shaped tail 8" long in p.a. 320 deg on Sept. 6.39). [IAUC 8195, 2003 September 6]
M. Hicks, Jet Propulsion Laboratory (JPL), reports the discovery of a comet on CCD images obtained via the NEAT project with the Haleakala 1.2-m telescope on September 23.60, noting the object to be slightly diffuse with a slight elongation to the west on images taken on Sept. 23.6 and 24.5 UT. Following posting on the NEO Confirmation Page, P. Birthwhistle, Great Shefford, U.K., reported that his CCD images taken with a 0.30-m reflector on Sept. 24.0 show a coma with diameter about 10" offset toward the southwest with a possible 30" tail in p.a. approximately 250 deg. J. Mahony, Lafayette, IN, communicates that his images with a 0.30-m Schmidt-Cassegrain reflector on Sept. 24.2 show a diffuse coma and a tail about 10" long in p.a. 250 deg. S. D. Gillam, JPL, obtained confirming images with the 0.6-m telescope at Table Mountain on Sept. 24.2, showing a coma of diameter approximately 10" with mag R = 18.3. Images taken with the 1.06-m KLENOT telescope at Klet by M. Tichy on Sept. 24.9 show a tail in p.a. 260 deg. [IAUC 8208, 2003 September 24]
Further to IAUC 8208, M. Hicks reports the NEAT discovery of another comet on images obtained at Haleakala on September 24.61, noting a coma diameter of 5" and a 15" tail in p.a. 255 deg. Following posting on the NEO Confirmation Page, numerous observers have reported cometary activity from CCD images obtained on Sept. 24.9-25.0 UT, including R. Apitzsch (Wildberg, Germany; 2" coma), P. Birtwhistle (not 'Birthwhistle', as given on IAUC 8208; 8" coma with a broad tail at least 20" long in p.a. 250 deg and a thin tail 20" long in p.a. 330 deg), F. Hormuth (Heppenheim, Germany; 40" tail in p.a. 260 deg), and S. Gajdos and A. Galad (Modra, Slovakia; coma diameter about 15" and tail extending in p.a. 255-260 deg). The available astrometry (including prediscovery LINEAR observations from Sept. 19.4), preliminary orbital elements (T = 2003 July 10.0 TT, Peri. = 259.6 deg, Node = 91.5 deg, i = 7.3 deg, equinox 2000.0, q = 2.294 UT, e = 0.454, P = 8.6 yr), and an ephemeris appear on MPEC 2003-S65. [IAUC 8209, 2003 September 25]
M. Bezpalko, Lincoln Laboratory, Massachusetts Institute of Technology, reports the LINEAR discovery of a comet on September 27.38, their images showing a tail in p.a. 260 deg. Following web-posting on the NEO Confirmation Page, J. Young reported that CCD images taken with the 0.6-m reflector at Table Mountain on Sept. 28.4 and 29.4 UT reveal a 5" coma and a straight, narrow tail 20" long in p.a. 65 deg and 57 deg, respectively. [IAUC 8211, 2003 September 29]
Nakano has identified a LINEAR asteroid 2002 XM113 with the comet.
An apparently asteroidal object discovered by LINEAR on September 26.17, and posted on the NEO Confirmation Page, has been found to have cometary appearance by several CCD observers, including J. Young and A. Grigsby (Table Mountain, 0.6-m reflector; 5" round coma and faint 10" outer shell on Sept. 30.1-30.2 UT, possibly slightly extended in p.a. 145 deg on Oct. 1.1-1.3); H. Mikuz (Crni Vrh, Slovenia; 0.60-m f/3 Deltagraph; diffuse coma of diameter about 10" on Sept. 30.8-30.9; mag 18.1-18.2), and J. E. McGaha (Tucson, AZ, 0.62-m f/5.1 reflector; 2" coma elongated to the southeast on Oct. 1.2). [IAUC 8213, 2003 October 1]
The comet has split into two components. Brian Marsden notes on MPEC 2004-U10 (2004 October 18) that The "original" and "future" barycentric values of 1/a for C/2003 S4-A are +0.025071 and +0.025582 (+/- 0.000004) AU^-1, respectively; those for C/2003 S4-B are +0.025069 and +0.025579 AU^-1.
Z. Sekanina, Jet Propulsion Laboratory, writes: "Application of my comet fragmentation model (Sekanina 1982, in Comets, Univ. of Arizona Press, p. 251) to this comet's observed duplicity (MPECs 2004-T44 and 2004-U10) shows that component B is the principal nucleus. This result is supported by the location of component A between components B and C, a suspected third fragment, on an image taken by R. Ferrando on 2004 Oct. 9 (see http://www.aerith.net/comet/catalog/2003S4/pictures.html). The astrometric observations made in Sept.-Oct. 2004 allow one to determine four of the model's five parameters for component A. The radial component of its separation velocity from B is indeterminate. Solutions with this velocity component assumed to point away from the sun provide marginally better data matches. When it is limited to a range from 0 to 2 m/s, the time of splitting comes out to be between 2004 May 23 and June 17 (3 days before to 22 days after perihelion) at 3.86 AU from the sun, with the differential nongravitational deceleration decreasing from 140 to 90 units of 10**-5 solar attraction and with the transverse and normal components of the separation velocity near 0.8 m/s in the direction opposite the orbital motion and 0.2 m/s pointing below the orbital plane, respectively. The high deceleration of the companion (nucleus A) indicates that it is a short-lived fragment with an estimated lifetime of 12-33 equivalent days. At a heliocentric distance of about 4 AU this means that the secondary can possibly be observed for several more months, unless the comet's rapid fading, apparently triggered by this nucleus fragmentation, continues. Predicted separations and position angles of A relative to B are as follows (0 TT, equinox 2000.0): 2004 Nov. 11, 12".9, 289 deg; Dec. 1, 13".9, 296 deg; Dec. 21, 14".7, 301 deg; 2005 Jan. 10, 15".5, 304 deg; Jan. 30, 16".5, 305 deg; Feb. 19, 17".8, 304 deg; Mar. 11, 19".6, 301 deg." [IAUC 8434, 2004 November 10]
An apparently asteroidal object reported independently by the NEAT (on September 24.18) and LONEOS (on September 27.16) projects has been found to show a nonstellar appearance in individual 30-s R-band images taken by A. Fitzsimmons and C. Snodgrass, Queen's University of Belfast, and O. Hainaut, European Southern Observatory (ESO), on 2004 Jan. 19.0 UT at the ESO 3.6-m New Technology Telescope (+ SUSI-2 camera). Fitzsimmons adds that co- addition of the frames shows an asymmetric coma of total mag 20.3 extending 1".7 in p.a. 130 deg. [IAUC 8274, 2004 January 23]
Keith Tritton provides the following information about the original disovery:
I'm amazed (and delighted) it's been recovered. It's quite a story - it was very faint on discovery in 1978 (I think it may even have been the faintest comet ever discovered at that time), when I was working on the Southern UK Schmidt Sky Survey. The orbit was observed over only a very short arc. The first return was very unfavourable, so it couldn't be seen, and the orbital inaccuracy was so large that the predictions for the second return had huge uncertainties. Nevertheless I got some plates taken at the Schmidt (this was about 1990) and sent to me in Cambridge for searching. But I never got them, they were lost in transit from Australia!
So I never expected to hear anything more about it. It must be rather rare to pick up a lost comet on its fourth return, mustn't it?
P. Holvorcem, Campinas, Brazil, has reported that the co- addition of three 45-s unfiltered CCD images of a fast-moving object found by C. Juels, Fountain Hills, AZ, with a 0.12-m f/5 refractor and a 0.5-m f/4.8 reflector on October 6.44 show a coma of diameter 2' and a hint of a 1'.5 tail at p.a. roughly 257 deg. Following posting on the NEO Confirmation Page, additional CCD observers noted the object's cometary appearance, including R. Trentman (Louisburg, KS, 0.75-m reflector; mag 13.1 and very faint evidence of a tail approximately 10" long in p.a. approximately 280 deg on Oct. 7.4 UT), D. T. Durig (Sewanee, TN, 0.30-m f/5.86 reflector; teardrop-shaped coma of mag 10.1 with a tail at least 2'-2'.5 long in p.a. about 285 deg on Oct. 7.4), and J. Young (Table Mountain, CA, 0.6-m reflector; 36" coma elongated to 48", with a 3' tail in p.a. 289 deg with a very straight and extremely thin jet of length about 1'.5 in its center on Oct. 7.5).
Following a suggestion by S. Hoenig (Dossenheim, Germany) from orbital computations by M. Meyer (Kelkheim, Germany), B. G. Marsden (Smithsonian Astrophysical Observatory) has shown that this comet is identical to the lost comet 1978d = 1977 XIII = D/1978 C2 (Tritton), which was observed for only a month (cf. IAUC 3175, 3186, 3194, 3198). The available astrometry, including Sept. 22 prediscovery observations, and the orbital elements by Marsden appear on MPEC 2003-T37. [IAUC 8215, 2003 October 7]
Observations in ICQ format, last observation 2003 October 8, updated 2003 October 25.
An apparently asteroidal object reported by LINEAR on October 13.44, and posted on the NEO Confirmation Page, has been found to show cometary appearance by several CCD astrometric observers, including R. Apitzsch (Wildberg, Germany, 0.24-m reflector; Oct. 14.0 UT, diffuse coma of diameter about 10"), J. E. McGaha (Tucson, AZ, 0.62-m reflector; Oct. 14.4, bright compact coma of diameter 4" with a fainter outer coma of diameter 10" and a broad tail 20" long in p.a. 30 deg), G. R. Jones (Tucson, AZ, 0.32-m reflector; Oct. 14.4, coma diameter about 6" and a possible tail at p.a. 35 deg), P. R. Holvorcem and M. Schwartz (Tenagra 0.81-m reflector at Nogales, AZ; Oct. 14.5, co-addition of three 120-s exposures shows a coma of diameter about 15" and total mag 15.1-15.6), and A. Knoefel and T. Payer (Essen, Germany, 0.32-m reflector; Oct. 14.9, short tail). [IAUC 8222, 2003 October 14]
Brian Marsden notes on MPEC 2004-A07 [2004 January 3] that the "original" and "future" barycentric values of 1/a are -0.000065 and +0.000653 (+/- 0.000024) AU**-1, respectively, suggesting that this is a "new" comet from the Oort cloud.
Vello Tabur, Australian Capital Territory, reports his discovery of a somewhat-condensed comet with a 30" coma on unfiltered CCD images taken with a 140-mm f/2.8 camera lens on Oct. 14.481 UT. T. Lovejoy (Thornlands, Queensland, 0.16-m reflector) reports that a CCD exposure taken on Oct. 15.5 shows a 0'.7 coma of total mag 11.6 and a fan-shaped tail about 1' long in p.a. 90 deg. [IAUC 8223, 2003 October15]
The latest MPEC and orbits by Hirohisa Sato give perihelion at 1.48 AU towards the end of April 2004. Sato's orbit suggests that the comet passed through the SOHO C3 coronagraph field between 2004 February 20 and 2004 March 25, though there were no conclusive observations reported. It emerged from solar conjunction as a 9th magnitude object in early May, however it was low in the summer twilight and not easy to observe. I glimpsed it in mid June, estimating it at around 10th magnitude. Observers in mid September estimated it at around 11.5. It will slowly fade through to the end of year, but remains in the morning sky.
Brian Marsden notes on MPEC 2004-A08 [2004 January 3] that the "original" and "future" barycentric values of 1/a are +0.000176 and +0.000878 (+/- 0.000043) AU**-1, respectively, suggesting that this is probably not a "new" comet from the Oort cloud.
31 observations received so far give a preliminary light curve, not corrected for aperture, but where possible corrected for systematic observer differences of m = 6.6 + 5 log d + 6.9 log r Observations in ICQ format, last observation 2004 September 19, updated 2004 December 30.
An apparently asteroidal object reported by LINEAR on October 13.45, and posted on the NEO Confirmation Page, has been found to show cometary appearance by several CCD astrometric observers, including J. E. McGaha (Tucson, AZ, 0.62-m reflector; Oct. 14.4 UT, coma diameter 6" with a fan-shaped tail 12" long in p.a. 75 deg), P. R. Holvorcem and M. Schwartz (Tenagra 0.81-m reflector at Nogales, AZ; Oct. 14.4 and 15.4, co-addition of three 180-s exposures on each night shows a coma of diameter about 5" and total mag 17.7-18.3), G. R. Jones (Tucson, AZ, 0.32-m reflector; Oct. 15.4, coma diameter 2", slightly elongated toward p.a. 40 deg), and J. Young (Table Mountain, CA, 0.6-m reflector; Oct. 15.5, 6" diffuse coma surrounding a very small central core). [IAUC 8224, 2003 October 15]
Brian Marsden notes on MPEC 2004-A09 [2004 January 3] that the "original" and "future" barycentric values of 1/a are +0.000169 and -0.000827 (+/- 0.000069) AU**-1, respectively, suggesting that this is probably not a "new" comet from the Oort cloud.
Brian Marsden further notes on MPEC 2005-G28 [2005 April 5] that the orbit is problematic. He gives non-gravitational parameters Y1 = +8.83 +/- 0.06, Y2 = -0.34 +/- 0.03. and comments:
For the past several weeks it has been evident that the "usual" procedure for handling orbital nongravitational effects is not working for this comet, if the desire is to obtain a consistent representation of the observations and some degree of future predictability. A fit to the observations since Oct. 2004, when water-ice vaporization could be expected to become significant, seems quite satisfactory but still gives the unusually large value of A1 = +12; on the other hand, as is rather to be expected, the observations during the previous twelve months are fully compatible with gravitational motion. The orbit provided above has been computed by S. Nakano using a formulation by S. Yabushita (1996, MNRAS 283, 347) that presumes more nongravitational activity at greater heliocentric distances and is based on carbon-monoxide vaporization.
I tentatively estimated
it at 13.4 on September 18.93. By November it was becoming easier to see, and had
brightened to 12.5.
Seiichi Yoshida noted that images taken by Giovanni Sostero on November 21 show a
61 observations received so far give a preliminary light curve of m = 7.8 + 5 log d + 6.6 log r Observations in ICQ format, last observation 2005 May 12, updated 2005 June 1.
Brian Marsden notes on MPEC 2004-K33 [2004 May 21] that "It is possible that C/2003 T12 has a short period and somewhat smaller perihelion distance, but the latter is limited by the minimum solar elongation of 5.3 deg. The object seems to have been too faint to show on SOHO-SWAN frames. Maike Meyer has calculated the periodic orbit, which has a period of 4.34 years and a perihelion distance of 0.46 AU.
Jim Danaher has set up a web page devoted to comet 2003 T12.
L. Manguso and H. Stange, Lincoln Laboratory, Massachusetts Institute of Technology, report the discovery of a comet with a definite halo but no tail on LINEAR images on October 19.38. Following posting on the NEO Confirmation Page, two other CCD observers have also commented on the cometary appearance: J. E. McGaha (Tucson, AZ, 0.30-m reflector; faint 10" coma elongated in p.a. 240 deg on Oct. 20.3 UT) and J. Young (Table Mountain, CA, 0.6-m reflector; coma of diameter 6" and mag 17.5 with a tail about 16" long in p.a. 276 deg). [IAUC 8227, 2003 October 20]
F. Shelly, Lincoln Laboratory, Massachusetts Institute of Technology, reports the discovery of a comet with a diffuse coma and a very wide, fan-shaped tail in p.a. 85 deg on LINEAR images on October 19.09. Following posting on the NEO Confirmation Page, other CCD observers have also commented on the cometary appearance on Oct. 21.1-21.2 UT, including J. Young at Table Mountain (0.6-m reflector; 5" coma without central condensation and with a fan-shaped tail about 25" long spanning p.a. 70-95 deg) and R. Fredrick and T. Medlock at Louisburg, KS (0.75-m reflector; 30" tail in p.a. 80 deg). [IAUC 8229, 2003 October 21]
K. Lawrence, Jet Propulsion Laboratory, reports the discovery by the NEAT project of a 19th magnitude comet on 2003 October 22.29. Observations by J. Young at Table Mountain on Oct. 23.2 UT show a 3" coma with a short, broad, fan-shaped tail about 8" long spanning p.a. 255-285 deg. [IAUC 8230, 2003 October 23]
An apparently asteroidal object with not-unusual motion, found by LONEOS on October 16.40 (the discovery observation together with other astrometry appeared on MPS 88336, 90581, and 91035 with the designation 2003 UD_16; initial orbit on MPO 53844), has been found by C. W. Hergenrother to show a circular, condensed 11" coma and no tail on co-added 900-s R-band CCD exposures taken on Nov. 30 with the Mt. Hopkins 1.2-m reflector (astrometry below measured by T. B. Spahr). [IAUC 8248, 2003 December 3]
Maik Meyer has found images of the comet on Palomar plates taken in 1989 and 1991, thus allowing a secure orbit to be determined. The comet was therefore numbered 159P.
Images of comet P/2003 UD_16 (cf. IAUC 8248) were identified and measured by M. Meyer from Palomar Sky Survey photographs taken on 1989 Dec. 17 and 1991 Feb. 19. [IAUC 8263, 2004 January 7]
An apparently asteroidal object discovered by the LINEAR project on 2003 October 29.32 has been found to show cometary appearance on CCD images taken with the Mt. Hopkins 1.2-m reflector on Nov. 30.25 UT by C. W. Hergenrother; his co-added 1200-s R-band exposures show a highly condensed 16" coma and a narrow tail 100" long in p.a. 280 deg (mag 18.5 determined by T. B. Spahr). Also, R. S. McMillan noted the object as diffuse in Spacewatch incidental observations made on Nov. 30.4. [IAUC 8247, 2003 December 2]
A. Milner, Lincoln Laboratory, Massachusetts Institute of Technology, reports the LINEAR discovery of a comet with a tail in p.a. 330 deg on 2003 November 4.47. Following posting on the NEOCP, other CCD observers recognized the object as a comet, reporting additional physical data: Nov. 5.2 UT, 12" coma (mag 16.5) and 40" tail (A. Knoefel, Essen, Germany, 0.32-m reflector); Nov. 5.5, 7" coma (mag 16.5) with a broad tail a little more than 70" long spanning p.a. 290-310 deg, including two or three streamers, the brightest of which is 30" long in p.a. 295 deg (J. Young, Table Mtn., CA, 0.6-m reflector); Nov. 5.5, coma diameter about 10", with 10" tail in p.a. 310 deg (P. R. Holvorcem and M. Schwartz, Nogales, AZ, 0.81-m reflector; three 180-s exposures); Nov. 6.4, soft coma of diameter 6", broad tail 9" long in p.a. 310 deg (J. E. McGaha, Tucson, AZ, 0.30-m reflector). [IAUC 8236, 2003 November 6]
Brian Marsden notes on MPEC 2004-B51 [2004 January 26] that the "original" and "future" barycentric values of 1/a are +0.001411 and +0.002242 (+/- 0.000035) AU^-1, respectively, suggesting that this is not a "new" comet from the Oort cloud.
An apparently asteroidal object reported by LINEAR on 2003 November 16.08 was posted on the NEO Confirmation Page and has been found to show cometary appearance by several CCD observers, including J. Young (Table Mountain, CA, 0.6-m reflector; Nov. 17.1 UT, very round coma of diameter 8" and mag 17.5 with a faint, featureless tail 50" long in p.a. 42 deg), R. Fredrick and R. Trentman (Louisburg, KS, 0.75-m reflector; Nov. 17.1, very diffuse tail approximately 4" long in p.a. 20 deg), J. E. Rogers (Camarillo, CA, 0.30-m reflector; Nov. 17.1, diffuse), and J. Lacruz (Madrid, Spain, 0.30-m reflector; Nov. 17.8, diffuse coma extending some 50" to the north). [IAUC 8239, 2003 November 17]
An apparently asteroidal object was discovered by the LINEAR project on 2003 Nov. 18 (observed on only two nights) and given the designation 2003 WC_7 (MPS 91151). The object was discovered independently on Jan. 31 by the Catalina Sky Survey and then posted on the NEO Confirmation Page. As a result, it has been found to show cometary appearance on CCD exposures taken by J. Young (Table Mountain, 0.6-m reflector, Feb. 1.15 UT; very diffuse coma of mag 17.5 and diameter 5", very little central condensation, and a straight, narrow 10" tail in p.a. 345 deg) and by G. J. Garradd and R. H. McNaught (Siding Spring, 1.0-m f/8 reflector, Feb. 1.46; coma diameter 3".5 in 2".5 seeing; no obvious tail visible in five co- added 40-s frames). [IAUC 8280, 2004 February 1]
As noted above the preliminary announcement of this asteroid suggested that it could be a Jupiter family comet, and this has proved to be the case. M Micheli (Italy) and Peter Jenniskens both suggested an identity with the lost periodic comet Blanpain (D/1819 W1), and Brian Marsden has now conclusively linked the asteroid with the comet. Harold Ridley has also tentatively linked the comet with the Phoenicid meteor shower of 1956 December 5. [IAUC 8485, 2005 February 13]
At discovery the comet was around 6.5, with a coma of 6 - 7 ' diameter. It was observed for 59 days. Although Vsekhsvyatskij gives an absolute magnitude of 8.5, this doesn't fit the ephemeris very well and 10.5 is more likely.
The original orbit for comet Blanpain appears to have been relatively good, however the period was around a month out. Since its discovery apparition it made a further 34 returns prior to its recovery as an asteroid in 2003. Perihelion distance has varied between 0.87 and 1.04 AU, and it passed 0.31 AU from Jupiter in 1995. There were close approaches to the Earth at the discovery in 1819 (0.11 AU in October before discovery), 1866 (0.08 AU in November), 1919 (0.06 AU in November/December). It will make future close approaches in 2020 (0.09 AU in January) and 2035 (0.09 AU in November). [Orbits calculated by Kenji Muraoka and myself]
Already more than a year ago, S. Foglia, Milan, Italy, reported a suggestion by M. Micheli that backward integration of the orbit of 2003 WY25 given on MPEC 2003-Y78 (Catalina Sky Survey discovery announcement on MPEC 2003-W41) suggested possible identity -- though showing discordances extending up to 17 deg in the argument of perihelion (Peri.) -- with the lost comet D/1819 W1 = 1819 IV, which was itself tentatively shown by H. B. Ridley (1957, BAA Circ. No. 382) to be related to the one-time Phoenicid meteor shower of 1956 Dec. 5. P. Jenniskens, NASA Ames Research Center, has now independently suggested the 1819-2003 identity with a Peri. discordance of 0.2 deg. Computations by B. G. Marsden, Harvard- Smithsonian Center for Astrophysics, that included reexamination of the 1819-1820 observations confirm a best-fit gravitational linkage with Peri. discordance 0.2 deg. He also showed that the discordances in all three angular elements can be reduced to 0.01 deg by starting from the following orbital elements for 2003 WY25 (which had H = 21.1 and was consistently of stellar appearance despite a passage only 0.025 AU from the earth on 2003 Dec. 12):
Epoch = 2003 Dec. 27.0 TT T = 2003 Dec. 11.5776 TT Peri. = 9.0695 e = 0.675583 Node = 69.3827 2000.0 q = 1.000069 AU Incl. = 5.9292 a = 3.082662 AU n = 0.1821022 P = 5.412 yearsAlthough backward integration of this orbit gives T too late in 1819, adjustment by Delta(T) = -4.28 days and modification of the angular elements within the range indicated above yield the result
Epoch = 1819 Nov. 22.0 TT T = 1819 Nov. 20.27 TT Peri. = 349.65 e = 0.7028 Node = 80.02 2000.0 q = 0.8893 AU Incl. = 9.23 a = 2.9928 AU n = 0.19036 P = 5.18 yearswhich satisfactorily represents 10 of the 13 observations made at Paris, Bologna, and Milan during 1819 Dec. 14-1820 Jan. 15 within 90 arcsec. The integrated orbital elements at the time of the Phoenicid shower are T = 1956 Oct. 25.32 TT, Peri. = 0.14 deg, Node = 74.37 deg, i = 9.60 deg (equinox 2000.0), q = 0.9914 AU, e = 0.6767, a = 3.0669 AU, P = 5.37 years. [IAUC 8485, 2005 February 13]
Observations in mid January 2004 demonstrated the presence of a coma, confirming the object as a comet. The latest orbit is hyperbolic, but perihelion remains a distant one at 5.19 AU in mid April 2006.
The Central Bureau has received word that a weak coma has been imaged for 2003 WT_42, an object originally reported as asteroidal by LINEAR (cf. MPEC 2003-W48, MPS 92017), by R. P. Binzel (at the Kitt Peak 4-m telescope) and by J. Licandro, M. Serra-Ricart, J. de Leon Cruz, and N. Pinilla-Alonso (at the 3.56-m Telescopio Nazionale Galileo + Near Infrared Camera- Spectrograph and the 2.5-m Nordic Optical Telescope + Andalucia Faint Object Spectrograph and Camera). Binzel reports that, in 1".5 seeing on 2003 Dec. 29.1-29.2 UT with the TV guider, 2003 WT_42 appeared distinctly more diffuse than stars of similar brightness, with a coma diameter of about 2"; broadband (500-900 nm) images showed larger north-south FWHM profiles when compared to stars of similar brightness. Licandro et al. report that a coma diameter of about 6"-10" (total mag R = 17.4 +/- 0.1; R-J = 0.8 +/- 0.15, which is close to the solar color) was clearly seen on simultaneous infrared and visible (broadband R and J_s) images of 2003 WT_42 obtained on 2004 Jan. 14.9. [IAUC 8270, 2004 January 16]
Brian Marsden notes on MPEC 2004-E05 [2004 March 1] that the "original" and "future" barycentric values of 1/a are +0.000207 and +0.000362 (+/- 0.000120) AU^-1, respectively, suggesting that this could be a "new" comet from the Oort cloud.
An apparently asteroidal object with not-unusual motion reported on Dec. 4 and 5 by the LINEAR project, and designated 2003 XD_10 on MPS 92917, was independently discovered with the NEAT 1.2-m Schmidt telescope at Palomar on Dec. 14.4 and reported then to be cometary (with a faint short tail toward the east-southeast) by K. J. Lawrence. Following posting on the NEO Confirmation Page, several other CCD observers have also noted the object's cometary nature, including P. Birtwhistle (Great Shefford, Berkshire, England, 0.30-m reflector; on Dec. 14.9, from co-added images totaling 15 min exposure, diffuse coma of diameter 10", extended in p.a. about 260 deg, surrounding a central condensation of mag 19.4; on Dec. 15.9, 8" coma and 45" tail in p.a. 255 deg), J. E. McGaha (Tucson, AZ, 0.36-m reflector; on Dec. 16.3, three co-added 1-min frames show a small starlike condensation with a 8" coma), J. Young (Table Mountain, CA, 0.6-m reflector; on Dec. 17.3, 3" asymmetric coma with a hint of tail about 12" long in p.a. 250-260 deg), and R. Fredrick and R. Trentman (Louisburg, KS, 0.75-m reflector; on Dec. 17.4, broad fan-shaped tail 20" long in p.a. 240 deg). [IAUC 8257, 2003 December 17]
The Catalina Sky Survey has reported observations of two short-tailed comet suspects on four CCD frames obtained over a 39-min span on Nov. 10.5 UT (observer R. Hill; 0.68-m Schmidt telescope). The head of the slightly fainter of the two was situated about 102" west and 33" north of that of the brighter and close to end of the latter's tail. Assuming that the two orbits differed only in T, B. G. Marsden, Harvard-Smithsonian Center for Astrophysics, found that the objects -- if real -- had to be intermediate-period comets some 4.3-4.4 AU from the earth. The assumption also revealed likely LINEAR observations of a single asteroidal object on Oct. 8 and 24, and a three-night linkage then showed identity with the LINEAR asteroidal object 2003 YM_159, observed on 2003 Dec. 17 and 30 (see MPS 109905) -- the identity clearly being with the brighter 2004 Nov. 10 object, now designated component A. T for component B will occur about 0.23 day later than for component A. [IAUC 8433, 2004 November 10]
The comet was originally named LINEAR-Catalina, however Brian Marsden notes on MPEC 2004-V79
Consultation with the IAU Committee on Small-Body Nomenclature has yielded the decision to introduce for this comet (cf. IAUC 8433, MPEC 2004-V52) the new principal designation P/2004 V5 and to replace the name LINEAR- Catalina with LINEAR-Hill. The components A and B are defined as before, although the opportunity has also been taken to reprint here the previously tabulated Nov. 10.5 observations with their new coded designations. The orbital elements and ephemeris refer to component A. Component B will pass perihelion 0.23 day after component A.
While the initial report inferred that the discovery of comet P/2003 YM_159 at Catalina was a team discovery (thus the name 'LINEAR-Catalina' given on IAUC 8433), it has since been determined that observer Rik Hill was alone in discovering, measuring, and reporting the comet -- thereby allowing his name to be used in place of the survey name (as also approved by the Catalina team). Consultation with the IAU Committee on Small-Body Nomenclature has yielded the decision to introduce for this comet the new principal designation P/2004 V5 and to replace the name 'LINEAR-Catalina' with 'LINEAR-Hill'. The components A and B are defined as before. The following improved orbital elements from MPEC 2004-V79 are for component A, with the preliminary elements for component B being well satisfied with the same elements but with Delta(T) = +0.23 day. [IAUC 8438, 2004 November 15]
Z. Sekanina, Jet Propulsion Laboratory, writes that his comet fragmentation model (cf. IAUC 8434) shows that the two nuclei of P/2004 V5 (MPECs 2004-V79 and 2004-W07) broke apart around 2001.9 +/- 0.3 year, at a heliocentric distance of about 6.3 AU and 2.5 years before perihelion. The separation velocity of the companion (fragment B) relative to the primary (A) pointed below the orbital plane and was at least 2.6 m/s. The motion of B has since been subjected to a differential deceleration of 40 +/- 6 units of 10**-5 the solar attraction. Predicted separations and position angles of B relative to A are as follows (equinox 2000.0): 2004 Nov. 21.0 TT, 131", 287 deg; Dec. 1.0, 137", 288 deg; 11.0, 144", 289 deg; 21.0, 152", 290 deg; 31.0, 159", 290 deg; 2005 Jan. 10.0, 167", 291 deg; 20.0, 175", 291 deg; 30.0, 181", 291 deg. [IAUC 8440, 2004 November 18]