53P/Van Biesbroeck

53P/Van Biesbroeck was discovered with the 61-cm reflector at Yerkes Observatory by George van Biesbroeck on September 1st 1954 as a 15th magnitude object. The comet was observed for over a year, but there was some difficulty in calculating an exact orbit for it. It was not until 1958 that definitive elements became available. The comet is unusual in the sense that its orbit is very close to a 1:1 resonance with Jupiter, in other words, it has almost exactly the same orbital period as Jupiter and is currently “locked” in position. The current period is 12.5 years, with perihelion at 2.42AU.

This is its fifth observed perihelion pass in 2002 (Perihelion being reached on October 9th) after the 1954, 1966, 1978, and 1991 passes. The comet is notable because it appears to have shared an orbit with 42P/Neujmin 3 in the 19th Century before a very close approach (0.04AU) to Jupiter. Calculations by Lubos Kresak suggest that the two comets appear to have split some time around 1850 and to have evolved into independent objects, before a close approach to Jupiter in 1850 the two objects had orbits that were identical to the limit of accuracy of the calculations.

The light curve brightens as a 10th power law, much slower than many short period comets. This shows that it does not have the thick surface dust mantle that suffocates the activity of more evolved comets.

Maximum will be reached around magnitude 14 in June 2003, well before perihelion, when the comet is at opposition and hence closest to the Earth. As it moves away from opposition the comet will fade considerably as the geocentric distance increases. At perihelion it will be 1AU further from Earth and approaching conjunction.

 

CCD observations in a 10 arcsecond aperture from: