Comet Prospects for 2002


2002 sees a number of returns of periodic comets, however none of them are particularly exciting.  The brightest periodic comet of the year is predicted to be P/Brewington, which is making its first predicted return early in 2003 and this comet may reach 10th magnitude at the end of the year.  Several long period comets discovered in previous years are still visible.  Theories on the structure of comets suggest that any comet could fragment at any time, so it is worth keeping an eye on some of the fainter periodic comets, which are often ignored.  This would make a useful project for CCD observers.  Ephemerides for new and currently observable comets are published in the Circulars, Comet Section Newsletters and on the Section, CBAT and Seiichi Yoshida's web pages.  Complete ephemerides and magnitude parameters for all comets predicted to be brighter than about 18m are given in the International Comet Quarterly Handbook; details of subscription to the ICQ are available from the comet section Director.  The section booklet on comet observing is available from the BAA office or the Director; a new edition is at the printers.


7P/Pons-Winnecke was discovered by Jean Louis Pons with a 0.12-m refractor at Marseilles in 1819, but was then lost until rediscovered by Friedrich August Theodor Winnecke with a 0.11-m refractor in Bonn in 1858.  He demonstrated the identity and recovered the comet in 1869.  The perihelion distance has slowly been increasing since the early 1800s.  It can make close approaches to the Earth and did so in 1927 (0.04 AU), 1939 (0.11), 1892 (0.12), 1819 (0.13) and 1921 (0.14).  An outburst of the meteor shower associated with the comet, the June Bootids, occurred on 1998 June 27.6.


It will be a morning object, becoming visible in February and reaching 11th magnitude in May after which it is unfavourably placed for observation from the UK.  Observers at lower latitudes will be able to follow it until September.  It moves eastwards, being in Serpens in February, Ophiuchus in March, Aquila in April and Aquarius in May.


Comet 19P/Borrelly reached perihelion in September 2001 and begins the year at 11m moving northward in Canes Venatici.  It remains quite well placed as it fades, passing into Ursa Major in late February when it is 12th magnitude.


22P/Kopff was discovered photographically by A Kopff at Konigstuhl Observatory in 1906, when it was around 11m.  The next return was unfavourable, but it has been seen at every return since then.  Following an encounter with Jupiter in 1942/43 its period was reduced and the perihelion distance decreased to 1.5 AU.  The following return was one of its best and it reached 8m.  The next return was unusual, in that it was 3m fainter than predicted until perihelion, when it brightened by 2m.  It suffered another encounter with Jupiter in 1954, but this made significant changes only to the angular elements.  1964 was another good return and the comet reached 9m.


UK observers may pick up the comet in March, when it is at opposition and follow it as it retrogrades in Virgo until May, but the comet is only 13th magnitude.  Although it continues to brighten, the solar elongation decreases and it is poorly placed when at its brightest (11m) at the end of the year.


29P/Schwassmann-Wachmann 1 is an annual comet which has frequent outbursts and seems to be more often active than not at the moment, though it rarely gets brighter than 12m.  It spends the year in Capricornus reaching opposition in early August, fairly close to Neptune.  The comet is an ideal target for those equipped with CCDs and it should be observed at every opportunity.  Unfortunately opportunities for UK observers are limited, as its altitude will not exceed 20° from this country.


Carl A Wirtanen discovered 46P/Wirtanen at Lick in 1948.  It is in a chaotic orbit, and its perihelion distance was much reduced due to approaches to Jupiter in 1972 and 1984.  It has been reported to outburst, but BAA data suggests that it was just rejuvenated after the perihelion distance was reduced.  It is a target for the Rosetta mission.  A December perihelion would give a close approach to the Earth, however the present period is exactly 5.5 years so that perihelia alternate between March and September.


The comet is also a morning object.  More southerly placed observers may pick it up in June, but UK observers will probably not find it until August, when it is fading from its best magnitude of 11.  The solar elongation only increases from around 40º to 60º by the end of the year, so it is never very well placed.  In June it is in Cetus, moving into Taurus in July, Gemini in August and Virgo in November.

67P/Churyumov-Gerasimenko was discovered in 1969 September, by Klim Churyumov and Svetlana Gerasimenko on a plate taken for 32P/Comas Sola at Alma Ata observatory.  It reached its present orbit after a very close encounter (0.05 AU) with Jupiter in 1959, which reduced the perihelion distance from 2.74 to 1.28 AU.  At a good apparition, such as in 1982, when it approached the Earth to 0.4 AU and was well observed by the comet section, it can reach 9m.


The comet is another morning object, and even at best it probably won’t exceed 12th magnitude.  Southern observers may pick it up around the solstice, but from the UK we won’t pick it up before August, when it will be fading.  Again the elongation is not good, increasing from around 50º to 100º at the end of the year.  The comet’s track closely parallels that of 46P/Wirtanen, entering Gemini in August and ending the year on the border of Leo and Virgo.


81P/Wild 2 is a new comet that made a very close (0.006 AU) approach to Jupiter in September 1974.  Prior to this it was in a 40 year orbit that had perihelion at 5 AU and aphelion at 25 AU.  The comet was discovered by Paul Wild with the 40/60-cm Schmidt at Zimmerwald on 1978 January 6.  The Stardust spacecraft is due to visit the comet in 2004 and recover material for return to earth in 2006.


The comet is at opposition in Taurus in December when it will be around magnitude 13.5.  It will brighten into 2003, when it is at perihelion, but is too close to the Sun for observation when at its brightest (11m).


95P/Chiron is an unusual comet in that it is also asteroid 2060.  It reaches 17m when at opposition in June in Sagittarius.  CCD V magnitudes of Chiron would be of particular interest as observations show that its absolute magnitude varies erratically.  It was at perihelion in 1996 when it was 8.5 AU from the Sun and will be nearly 19 AU from the Sun at aphelion in around 50 years time.


The orbit of 96P/Machholz 1. is very unusual, with the smallest perihelion distance of any short period comet (0.13 AU), which is decreasing further with time, a high eccentricity (0.96) and a high inclination (60°).  Studies by Sekanina suggest it has only one active area, which is situated close to the rotation pole and becomes active close to perihelion.  The comet may be the parent of the Quadrantid meteor shower.  It is rarely sufficiently well placed to see visually and this return is no exception.  However, at perihelion on 2002 January 8 it is only a few degrees from the Sun and may be seen in the SOHO LASCO coronagraphs from January 5 to 11.


116P/Wild 4 was discovered on 1990 January 21.98 by Paul Wild with the 0.40-m Schmidt at the Zimmerwald station of the Berne Astronomical Institute at a photographic magnitude of 13.5.  At its brightest the comet only reached 12m, but it was surprisingly well observed.  The comet was perturbed into its present orbit after a close approach to Jupiter in mid 1987.


The comet emerges from the solar glare in November, moving south-eastwards in Virgo, but is poorly placed for viewing from the UK.  It brightens from 13th magnitude near the end of the year to 12th magnitude in April as it nears opposition but is a long way south and will be difficult to observe from the UK.  It is at perihelion in January 2003.


P/Shoemaker 3 (1986 A1) is also making its first return since discovery.  It will be quite faint, around 14-13th magnitude, when it is picked up in November and does not get much brighter by the time it reaches opposition in February 2003.  It moves eastwards from Cancer into Leo at the end of the year.


P/Brewington 2 (1992 Q1) makes its first return since its discovery in 1992.  It was discovered by Howard J Brewington of Cloudcroft, New Mexico, as a small diffuse 10m object on August 28.41 using a 0.40-m reflector x55.  This was his fourth discovery and his second periodic one.  The comet is in a Jupiter crossing orbit, but has not approached the planet for several revolutions.  At a favourable return it could reach 7m.


It will be too far south for viewing from the UK when it gets into visual range in June.  It reaches opposition in August when it may be 12th magnitude and continues to brighten.  We may pick it up in November as it brightens to 10th magnitude and we will be able to follow it into the New Year as it continues to move north.  It is an evening object, but its solar elongation decreases from 80º in November to 50º at the end of the year.  It will not reach perihelion until 2003.  By October it is moving north-eastwards in Capricornus and ends the year in Aquarius.


Several recently discovered parabolic comets will be visible during 2002.  2000 SV74 (LINEAR) will be fading from 13th magnitude and may remain visible until December.  2000 WM1 (LINEAR) begins the year too far south to be visible from the UK, but it is well placed for Southern Hemisphere observers and may be a binocular object.  In March it will have moved far enough north for UK observation and should still be a binocular object as it emerges into the morning sky in Sagittarius.  It continues to move rapidly north and will probably be best for northern viewers in mid month when the moon is out of the sky.  It passes from Aquila into Hercules in April and will probably be too faint for easy observation by June.  2001 N2 (LINEAR) may reach 13th magnitude between May and August.  2001 HT50 (LINEAR) will become visible towards the end of the year as it brightens towards its perihelion in mid 2003.  2001 MD7 (P/LINEAR) may be visible to Southern Hemisphere observers at the beginning of the year fading from around 13th magnitude.


Several other comets return to perihelion during 2002, however they are unlikely to become bright enough to observe visually or are poorly placed. 6P/d’Arrest, 15P/Finlay, 26P/Grigg-Skjellerup and 28P/Neujmin 2 have unfavourable returns. 30P/Reinmuth 1, 31P/Schwassmann-Wachmann 2, 39P/Oterma, 54P/de Vico-Swift, 57P/du Toit-Neujmin-Delporte, 77P/Longmore, 89P/Russell 2, 90P/Gehrels 1, 92P/Sanguin, 115P/Maury, 124P/Mrkos, 125P/Spacewatch, 1999 F1 (Catalina), 2001 C2 (LINEAR), 2001 K5 (LINEAR) and 2001 R1 (P/LONEOS) are intrinsically faint or distant comets.  Ephemerides for these can be found on the CBAT WWW pages.  18D/Perrine-Mrkos has not been seen since 1968.


Looking ahead, 2003 has a good return of 2P/Encke, which might be observable from September until the end of the year, when it could be 6th magnitude.  This may however be optimistic as observations from the SOHO spacecraft in 2000 showed that it suddenly brightened after perihelion, which does not occur until late December 2003.



Comets reaching perihelion in 2002









 96P/Machholz 1

 Jan  8.6






2001 X1 (LINEAR)

 Jan  9.0






 31P/Schwassmann-Wachmann 2

 Jan 18.4






2000 WM1 (LINEAR)

 Jan 22.7







 Jan 28.1






2001 T3 (P/NEAT)

 Feb  1.1







 Feb  3.6







 Feb  7.2






1999 F1 (Catalina)

 Feb 13.7






2001 R1 (P/LONEOS)

 Feb 17.6






2001 OG108 (A/LONEOS)

 Mar 15.2






 89P/Russell 2

 Mar 23.0






2001 C1 (LINEAR)

 Mar 28.3






2000 SV7 (LINEAR)

 Apr 30.5







 May 15.7






2001 T4 (NEAT)

 May 15.8






 90P/Gehrels 1

 Jun 23.0







 Jul 27.0






 57P/du Toit-Neujmin-Delporte

 Jul 31.2






 54P/de Vico-Swift

 Aug  7.5






2001 U6 (LINEAR)

 Aug  8.5






2001 X2 (P/Scotti)

 Aug 10.3







 Aug 18.3






2001 N2 (LINEAR)

 Aug 19.6







 Aug 27.0







 Sep  4.7







 Sep 10







 Sep 23.1






2001 K5 (LINEAR)

 Oct 11.9







 Nov 29.7







 Dec 12.1






   P/Shoemaker 3

 Dec 15.0







 Dec 22.2







 Dec 22.4







 Dec 23.9






 30P/Reinmuth 1

 Dec 24.4






 28P/Neujmin 1

 Dec 27.4








The date of perihelion (T), perihelion distance (q), period (P), the number of previously observed returns (N) and the magnitude parameters H1 and K1 are given for each comet.


Note: m1 = H1 + 5.0 * log(d) + K1 * log(r)



References and sources


Nakano, S. and Green D. W. E., Eds, International Comet Quarterly 2002 Comet Handbook, (2001).

Shanklin, J. D.,  Observing Guide to Comets, 2nd edition (2001)

Marsden, B. G.  Catalogue of Cometary Orbits, 13th edition, IAU CBAT, (1999).

Kronk, G. W., Cometographia, Cambridge University Press, (1999).

Belyaev, N. A., Kresak, L., Pittich, E. M. and Pushkarev, A. N., Catalogue of short Period Comets, Bratislava (1986).


Jonathan Shanklin