38P/Stephan-Oterma (0038P)

TRY AGAIN 2055

Type: Periodic Perihelion date: 10 November 2018 Perihelion distance (q): 1.6 Aphelion distance (Q) : 20.9 Period (years): 37.7 Eccentricity (e): 0.86 Inclination (i): 18.4 JPL orbit diagram COBS lightcurve J. E. Coggia (Marseilles, France) found what he thought was an uncataloged nebula on 22 January 1867. The sky clouded up almost immediately and remained completely cloudy until the night of 24 January, when E. J. M. Stephan (Marseille, France) checked on the nebula through a brief break in the clouds and saw that it had moved. Stephan was able to confirm this was a comet on 25 January. Stephan said the comet was rather brillant, round, with a very marked nucleus. Liisi Oterma (Turku, Finland) discovered this comet on 6 November 1942. It was described as magnitude 13. Oterma confirmed the discovery on 6 November. A short time after the announcement, Fred L. Whipple (Harvard College Observatory, Massachusetts, USA) found a pre-discovery image on a patrol plate exposed on 5 November. Close approaches to planets: • 0.92 AU from Earth on 25 November 1866 • 1.66 AU from Jupiter on 17 January 17 1903 (increased perihelion distance from 1.575 AU to 1.588 AU, increased orbital period from 37.12 to 38.44 years) • 0.63 AU from Earth on 7 December 1942 • 0.59 AU from Earth on 9 December 1980 • 1.95 AU from Jupiter on 26 March 1982 and 1.42 AU from Saturn on 1 June 1 1984 (increased perihelion distance from 1.574 AU to 1.588 AU, increased orbital period from 37.71 to 37.96 years) • 0.77 AU from Earth on 17 December 2018 • 0.70 AU from Earth on 3 November 2056 Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 09-Aug-18 14.95 0.04 11.9 1.3 12-Sep-18 13.94 0.04 11.0 1.1 20-Sep-18 14.07 0.01 12.0 1.6 08-Nov-18 13.28 0.01 10.3 2.2 18-Nov-18 13.14 0.04 10.0 2.9 02-Dec-18 13.22 0.01 9.8 3.1 09-Dec-18 13.28 0.02 10.0 2.8 16-Dec-18 13.26 0.03 9.9 4.2 30-Dec-18 13.40 0.01 10.2 3.7 05-Jan-19 13.38 0.02 10.0 3.2 12-Jan-19 13.54 0.01 10.6 2.5 28-May-19 18.08 0.04 14.9 0.4 04-Jun-19 18.48 0.11 16.1 0.4