Comet 155P/Shoemaker 3 was discovered by Carolyn and Gene Shoemaker with the 46cm Schmidt camera on Palomar Mountain on January 10th 1986. The comet was magnitude 10 and had a short tail.
Calculations by Brian Marsden gave a first estimate of the period of 15.3 years, and an overall orbit which was very close to the accepted one despite being based on an arc of only 10 days.
The orbital period is a relatively long 17.11 years and the perihelion distance 1.814AU. The comet was recovered independently on September 9th 2002 by T.Aribe and by A. Nakamura on September 12th. It will reach perihelion on December 14th 2002
The light curve here is made up of CCD photometry in R with a 10" aperture (shown as m2) and aperture photometry with an 18.7 arcsecond aperture. The comet has the very fast rate of brightening with heliocentric distance typical of a highly evolved object with a thick mantle that insulates the surface ices. This is a rather poor apparition and the comet was not expected to get much brighter than magnitude 15 in January 2003.
The light curve data in the 10 arcsecond aperture shows a sharp drop in brightness after perihelion rather than the continued brightening, although the total magnitude did reach aapproximately R=13 in January 2003.
CCD observations in a 10 arcsecond aperture from:
CCD aperture photometry in 12", 18".7 and 2'.5 apertures by:
Image: December 26th 2002
Image of 155P/Shoemaker 3 taken with a 0.30-m f/6.5 Schmidt-Cassegrain + ST9-E CCD from close to Barcelona (Spain).
The comet shows a faint tail to the upper left of the image and a condensed coma.
Ramón Naves & Montse Campàs
MPC 213, OBSERVATORIO MONTCABRER CABRILS (SPAIN)
Coma profile: January 24th 2003
Profile of the coma of 155P/Shoemaker 3.
Obtained by CCD photometry with apertures of 10, 20, 30, 40 and 60 arcseconds.