117P/Helin-Roman-Alu (0117P)

Type: Periodic Perihelion date: 7 July 2022 Perihelion distance (q): 3.0 Aphelion distance (Q) : 5.1 Period (years): 8.3 Eccentricity (e): 0.26 Inclination (i): 8.7 JPL orbit diagram COBS lightcurve The comet was discovered by Eleanor F. Helin, Brian P. Roman, and Jeff Alu (Palomar Observatory, California, USA) on images obtained with the 0.46-m Schmidt telescope on 2 October 1989. They described it as diffuse with some condensation, and estimated the magnitude as 17.5 and confirmed the comet on October 5 and 6. James V. Scotti (Steward Observatory, Kitt Peak, USA) detected the comet with a 0.91-m telescope on 24 January 1993, when it was near aphelion. The magnitude was given as 21.2 and the comet was then 5.25 AU from the sun. This showed the comet was visible throughout its orbit. It is a Quasi-Hilda comet. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 19-Jan-13 17.03 0.03 16.8 0.2 29-Jan-13 16.68 0.03 16.1 0.3 04-Mar-13 16.52 0.02 16.2 0.2 17-Mar-13 16.23 0.00 15.8 0.3 03-Apr-13 15.90 0.02 15.1 0.4 17-Apr-13 15.22 0.02 14.4 0.5 02-May-13 14.88 0.01 14.1 0.5 27-May-13 15.20 0.05 14.5 0.3 09-Jun-13 15.40 0.01 14.5 0.4 24-Jun-13 15.46 0.08 13.3 0.3 05-Jul-13 15.64 0.04 14.5 0.3 24-Jul-13 15.58 0.04 14.5 0.3 10-Aug-13 15.55 0.02 14.5 0.4 16-Apr-14 15.50 0.04 13.9 0.2 21-May-14 15.37 0.01 14.4 0.3 08-Jun-14 15.20 0.02 14.2 0.3 02-Jul-14 14.88 0.02 13.5 0.3 16-Jul-14 14.71 0.02 13.3 0.3 26-Jul-14 14.59 0.02 13.3 0.3 05-Aug-14 14.56 0.03 13.1 0.4 20-Aug-14 14.65 0.04 13.1 0.4 14-Sep-14 15.10 0.02 13.3 0.4 27-Sep-14 15.17 0.01 13.4 0.7 07-Oct-14 15.28 0.03 13.6 0.5 20-Oct-14 15.42 0.02 13.4 0.4 27-Oct-14 15.47 0.03 13.8 0.6 17-Nov-14 15.65 0.03 14.1 0.5 20-Jun-15 16.86 0.05 15.8 0.2 04-Jul-15 16.77 0.16 16.2 0.2 19-Jul-15 16.73 0.05 16.0 0.2 09-Aug-15 16.60 0.03 14.7 0.2 15-Aug-15 16.66 0.04 15.6 0.3 22-Aug-15 16.57 0.01 15.6 0.3 07-Sep-15 16.51 0.02 15.4 0.2 16-Sep-15 16.36 0.01 15.4 0.3 23-Sep-15 16.30 0.01 15.2 0.3 07-Oct-15 16.18 0.01 15.0 0.4 18-Oct-15 16.13 0.02 15.0 0.3 31-Oct-15 16.31 0.03 15.2 0.4 09-Nov-15 16.33 0.01 15.2 0.3 16-Nov-15 16.41 0.02 14.7 0.2 03-Dec-15 16.62 0.02 15.3 0.3 13-Dec-15 16.76 0.01 15.3 0.4 30-Aug-16 18.22 0.27 15.4 0.2 15-Sep-16 18.04 0.06 15.7 0.2 28-Sep-16 18.06 0.06 17.0 0.2 29-Oct-16 17.84 0.04 17.3 0.2 10-Nov-16 17.67 0.18 16.1 0.3 23-Nov-16 17.39 0.03 16.4 0.3 19-Dec-16 17.81 0.02 16.7 0.3 26-Dec-16 17.93 0.14 15.6 0.2 22-Jan-20 18.74 0.07 18.4 0.3 31-Jan-20 18.41 0.07 18.2 0.3 16-Feb-20 18.14 0.04 17.9 0.3 19-Mar-20 18.57 0.17 18.2 0.3 10-Jan-21 16.8 0.4 13-Jan-21 16.8 0.4 23-Jan-21 17.64 0.09 16.8 0.4 07-Feb-21 16.8 0.4 14-Feb-21 17.24 0.04 16.4 0.4 22-Feb-21 16.3 0.4 13-Mar-21 16.66 0.03 16.1 0.4 18-Mar-21 15.2 0.4 02-Apr-21 16.20 0.01 15.5 0.4 10-Apr-21 15.5 0.4 16-Apr-21 15.2 0.4 02-May-21 16.04 0.03 15.1 0.4 14-May-21 16.10 0.15 15.5 0.4