91P/Russell (0091P)

Type: Periodic Perihelion date: 9 November 2020 Perihelion distance (q): 2.6 Aphelion distance (Q) : 5.2 Period (years): 7.7 Eccentricity (e): 0.33 Inclination (i): 14.1 JPL orbit diagram COBS lightcurve Kenneth S. Russell (U. K. Schmidt Telescope Unit, Siding Spring, Australia) discovered this comet on plates exposed with the 1.24-m Schmidt on 14 and 15 June 1983. He estimated the magnitude as 16 and said it exhibited a tail 3-4 arc minutes long. The comet was confirmed by J. Gibson (Palomar Observatory, California, USA) on 17 June when a photograph with the 1.22-m Schmidt indicated a nuclear magnitude of about 17 and a weak tail extending about 2 arc minutes toward the west. The comet was next expected to return to perihelion during May of 1990. It was recovered on 1 and 2 January 1989, by Gibson. He said the CCD images obtained with the 1.5-m reflector indicated a nuclear magnitude near 20. He added that a faint coma about 5 arc minutes across was visible and contained a sharp central condensation. James V. Scotti (University of Arizona) observed the comet with the Spacewatch 0.91-m telescope on 18 and 19 November 1989. He determined the magnitude as 21.0 to 21.4 and said the comet was stellar in appearance. The comet was followed until 28 May 1990, at which time Seki estimated the total magnitude as 16. The comet was expected at perihelion during November 1997 during its next apparition and Scotti recovered it with the 0.91-m Spacewatch telescope on 18 November 1996. He determined the total magnitude as 21.3. The comet was observed by several observatories on a number of occasions during 1997 and 1998. On 1998 May 29 it was estimated as magnitude 18.0 by observers at the Astronomical and Geophysical Observatory at Modra. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 18-Feb-20 20.32 0.18 20.0 0.2 03-Mar-20 19.93 0.14 19.4 0.3 19-Mar-20 19.91 0.29 19.3 0.3 29-Mar-20 19.76 0.09 19.5 0.2 24-May-20 19.71 0.29 19.2 0.2