Electronic Telegram No. 4395 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network COMET P/2016 WM_48 (LEMMON) An apparently asteroidal object found on CCD images obtained at Mount Lemmon in southern Arizona on 2016 Nov. 30 UT and given the minor-planet designation 2016 WM_48 (cf. MPEC 2016-X29) has been found to show cometary appearance by CCD astrometrists elsewhere. The discovery observations tabulated below include those obtained by R. A. Kowalski with the Mount Lemmon Survey 1.5-m reflector, together with observations made by J. A. Johnson with the Steward Observatory 1.0-m reflector at Mt. Lemmon Station and LINEAR survey observations obtained with the 3.5-m f/1 Space Surveillance Telescope on Atom Peak in the White Sands Missile Range, NM, USA. 2016 UT R.A. (2000) Decl. Mag. Observer Nov. 30.14694 4 09 09.00 + 3 42 56.5 19.2 LINEAR 30.15180 4 09 07.31 + 3 43 04.5 19.4 " 30.15666 4 09 05.61 + 3 43 12.0 19.0 " 30.16159 4 09 03.87 + 3 43 20.1 19.3 " 30.16638 4 09 02.21 + 3 43 27.9 18.7 " 30.17150 4 09 00.43 + 3 43 35.9 19.3 " 30.24294 4 08 35.46 + 3 45 30.7 19.0 Kowalski 30.24723 4 08 33.98 + 3 45 37.3 19.0 " 30.25543 4 08 31.09 + 3 45 51.1 18.8 " 30.25971 4 08 29.58 + 3 45 58.1 18.9 " 30.27999 4 08 22.46 + 3 46 30.6 19.1 Johnson 30.28108 4 08 22.11 + 3 46 32.8 18.9 Kowalski 30.28124 4 08 22.04 + 3 46 33.0 18.7 Johnson 30.28249 4 08 21.58 + 3 46 34.2 19.2 " 30.28254 4 08 21.58 + 3 46 34.0 19.1 Kowalski 30.28374 4 08 21.19 + 3 46 36.6 19.0 " 30.28393 4 08 21.07 + 3 46 36.5 18.9 Kowalski 30.28523 4 08 20.64 + 3 46 38.8 19.0 " 30.40555 4 07 38.46 + 3 49 52.2 18.8 Johnson 30.40907 4 07 37.21 + 3 49 58.1 19.1 " 30.41274 4 07 35.96 + 3 50 03.8 19.0 " H. Sato, Tokyo, Japan, writes that ten stacked 60-s exposures taken on 2017 May 23.46 UT with an 0.61-m f/6.5 astrograph (+ luminance filter) at the Sierra Remote Observatory, Auberry, CA, USA, shows 2016 WM_48 to be strongly condensed with an outer coma 12" in diameter and no tail; the w-band magnitude was 18.2 as measured within a circular aperture of radius 6".3; Sato adds that follow-up images taken with an iTelescope 0.51-m f/6.8 astrograph (+ luminance filter) near Mayhill, NM, USA, on May 24.4 show a strongly condensed coma 12" in diameter with w-band magnitude 18.4 as measured within a circular aperture of radius 6".5. After being alerted by Sato, L. Buzzi reports that ten stacked 60-s exposures were taken by a large group of observers (P. Miller, E. Gomez, R. Holmes, Buzzi, S. Foglia, R. Miles, and T. Linder) with the 2-m f/10 "Faulkes Telescope North" at Haleakala during May 27.6 in 1".0 seeing, which show the comet to be very diffuse with a coma at least 6"-8" wide and only a weak central condensation; Buzzi adds that astrometry was quite difficult due to the object's diffuseness. The available astrometry, the following orbital elements by G. V. Williams (from 156 observations spanning 2016 Nov. 30-2017 May 27), and an ephemeris appear on MPEC 2017-K72. Epoch = 2017 Feb. 16.0 TT T = 2017 Feb. 26.78606 TT Peri. = 35.85715 e = 0.7866961 Node = 59.87472 2000.0 q = 1.7480649 AU Incl. = 117.54823 a = 8.1951836 AU n = 0.04201129 P = 23.46 years NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2017 CBAT 2017 May 28 (CBET 4395) Daniel W. E. Green