158P/Kowal-LINEAR (0158P)

Type: Periodic Perihelion date: 15 May 2021 Perihelion distance (q): 4.8 Aphelion distance (Q) : 5.1 Period (years): 11.0 Eccentricity (e): 0.03 Inclination (i): 8.0 JPL orbit diagram COBS lightcurve Charles T. Kowal (Palomar Observatory, California, USA) found images of this comet in late August 1979 on photographic plates exposed one month earlier with the 1.20- m Schmidt telescope. The earliest image was obtained on 24 July, while two additional images were obtained on 25 and 27 July. Although three images of the comet were found on plates exposed over a period of four days, because more than a month had passed no further observations were acquired. Two days after the initial announcement, B. G. Marsden calculated a parabolic orbit with a perihelion date of 23 January 1978 and provided an ephemeris covering the period of 15 August to 24 September. He noted, "It is rather probable that the comet is a short-period one." Marsden added that if the comet was periodic, the ephemeris could be uncertain by up to one degree. The comet was observed by the Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) project on 12 September 2001 and was reported as a minor planet of magnitude 19.1. It was subsequently found on additional LINEAR images obtained on 25 August. After the orbit was well established, a prediscovery image was found on a plate exposed with the 1.2-m Schmidt at Siding Spring (Australia) on 23 September 1990. This "minor planet" was observed off and on for the next two years, following its discovery. Then on 26 November 2003, A. E. Gleason (Kitt Peak Observatory, Arizona, USA) imaged the object with the 0.9-m Spacewatch reflector and noted a condensed coma 6 arc seconds across that exhibited a tail extending 18 arc seconds toward PA 265°. The Minor Planet Center made a request for confirmation and J. Young (Table Mountain Observatory, California, USA) obtained a CCD image on 27 November which revealed a coma 4 arc seconds across and a broad, faint tail extending 12 arc seconds toward PA 265°. Knowing that this was now a comet that should be detectable throughout its orbit, a search was made for older images. Soon images were reported at Siding Spring from 23 September 1990 and at Palomar Observatory from 11 November 1993. On 2 December, S. Nakano linked this comet to the lost comet reported by Kowal back in 1979. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 05-Aug-13 19.91 0.23 19.8 0.2 03-Nov-13 18.25 0.18 17.8 0.3 13-Nov-13 18.15 0.27 16.5 0.2 23-Nov-13 18.45 0.19 18.1 0.2 09-Dec-13 18.58 0.08 18.3 0.2 27-Dec-13 18.72 0.13 18.2 0.3 07-Jan-14 18.74 0.40 18.4 0.2 24-Nov-14 19.41 0.18 19.0 0.2 19-Dec-14 18.83 0.15 18.5 0.2 28-Dec-14 18.74 0.11 18.6 0.2 11-Mar-15 19.31 0.09 19.2 0.2 09-Dec-15 19.81 0.15 19.6 0.2 04-Feb-16 18.72 0.07 17.5 0.2 28-Mar-16 19.29 0.07 18.9 0.2 01-Mar-17 19.37 0.08 18.9 0.2 14-Feb-18 20.06 0.16 19.6 0.2 09-Mar-18 19.52 0.20 18.7 0.2 17-Mar-18 19.67 0.12 19.6 0.2 05-Apr-18 19.45 0.09 19.2 0.2 16-Apr-18 19.40 0.20 19.0 0.2 07-Jun-18 19.58 0.20 19.1 0.2 09-May-19 19.40 0.10 18.8 0.2 02-Jun-19 19.12 0.10 18.3 0.2