Comet P/2019 A6 (Lemmon-Panstarrs)

An apparently asteroidal object reported from observations obtained by A. R. Gibbs and R. A. Kowalski with the Mt. Lemmon 1.5-m reflector on 2018 Dec. 14 and 19, respectively, and with the Pan-STARRS1 1.8-m Ritchey-Chretien telescope at Haleakala on 2018 Dec. 16 and 2019 Jan. 7, has been found to show cometary appearance; the first four nights of available astrometry are tabulated below. R. Weryk and R. Wainscoat, Institute for Astronomy, University of Hawaii, reported that four w-band Pan-STARRS1 images taken on Jan. 7.5 UT showed marginally that this might be a comet, with the image having full-width-at-half-maximum of about 1".7 in the best seeing (1".4), with a slight asymmetry suggesting a tail extending to the northwest. 2018 UT R.A. (2000) Decl. Mag. Observer Dec. 14.43864 9 17 54.34 - 2 09 12.9 20.4 Gibbs 14.44460 9 17 54.25 - 2 09 21.0 " 14.51767 9 17 52.72 - 2 10 55.3 20.6 " 14.51877 9 17 52.72 - 2 10 56.7 20.5 " 14.51987 9 17 52.68 - 2 10 58.0 20.4 " 14.52097 9 17 52.67 - 2 10 59.6 20.5 " 16.53584 9 17 11.14 - 2 54 09.3 20.4 Pan-STARRS1 16.54823 9 17 10.81 - 2 54 25.0 20.2 " 16.56060 9 17 10.51 - 2 54 40.8 20.7 " 19.36815 9 15 58.65 - 3 53 57.7 20.5 Kowalski 19.37335 9 15 58.46 - 3 54 04.1 20.5 " 19.37854 9 15 58.32 - 3 54 10.9 20.2 " 19.38376 9 15 58.18 - 3 54 16.6 20.9 " Jan. 7.51449 9 01 17.92 - 9 54 29.2 20.7 Pan-STARRS1 7.52615 9 01 17.19 - 9 54 40.4 20.6 " 7.53780 9 01 16.45 - 9 54 51.7 20.6 " 7.54948 9 01 15.71 - 9 55 02.9 20.6 " Weryk and Wainscoat obtained three 60-s confirming gri-band images with the 3.6-m Canada-France-Hawaii Telescope on 2019 Jan. 8.65 UT (queue observer D. Woodworth, queue coordinator A. Petric), which show a very-low-surface- brightness tail extending for at least 20" towards p.a. 320 degrees (not in the direction of the comet's apparent motion); tracking was imperfect, but they measured FHWM = 1".0 in 0".8 seeing. Gibbs reported that sixteen co-added 30-s CCD images obtained with the Steward Observatory's 1.0-m reflector at Mt. Lemmon in poor transparency on Jan. 9.4 show a 5" tail in p.a. 315 deg. After the object was posted on the Minor Planet Center's PCCP webpage, CCD astrometrists elsewhere also reported on the cometary appearance. H. Sato, Tokyo, Japan, writes that twelve stacked 60-s exposures taken on Jan. 8.6 with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring show a strongly condensed coma 10" in diameter with a hint of tail 10" long toward p.a. 50 degrees; the magnitude was 19.5 as measured within a circular aperture of radius 6".5. R. S. McMillan found a 3" tail pointed northward on R-band images obtained in 2".5 seeing with the Spacewatch II 1.8-m f/2.7 reflector at Kitt Peak on Jan. 17.3.