Electronic Telegram No. 4379
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


COMET C/2017 E5 (LEMMON)
     An apparently asteroidal object found on CCD survey images taken by G. J.
Leonard with the Mount Lemmon 1.5-m reflector near Tucson (discovery
observations tabulated below) has been found to show cometary appearance on
images taken by CCD astrometrists elsewhere

     2017 UT             R.A. (2000) Decl.       Mag.   Observer
     Mar.  4.40551   13 54 55.79   +31 48 08.4   20.1   Leonard
           4.41079   13 54 55.33   +31 48 16.1   19.9     "
           4.41725   13 54 54.92   +31 48 24.6   19.9     "
           4.45927   13 54 51.52   +31 49 24.7   19.7     "
           4.46616   13 54 51.10   +31 49 35.6   20.1     "
           4.47305   13 54 50.45   +31 49 46.1   20.0     "
           4.47990   13 54 49.94   +31 49 55.9   19.8     "

R. Weryk, Institute for Astronomy, University of Hawaii, reports that four
stacked i-band images taken with the 1.8-m Pan-STARRS1 telescope at Haleakala
on Mar. 6.5 UT show a short 3" tail towards p.a. about 210 degrees; the coma
has a FWHM of about 1".5 in a stacked image, compared to 1".0 for neighboring
stars.  Weryk adds that a search of Pan-STARRS1 images yielded two additional
i-band detections on 2017 Feb. 9.6, though the object is too faint to
reliably discern any cometary activity (mag 21.1-21.3).  Eighteen stacked
120-s mages taken by G. Favero and R. Furgoni with a 0.80-m f/4 reflector at
the Osservatorio del Celado (Castello Tesino, Italy) on Mar. 16.9 show a
diffuse appearance and a hint of elongation at p.a. about 180 deg.
     The available astrometry, the following retrograde elliptical orbital
elements by G. V. Williams (from 72 observations spanning Feb. 9-Mar. 31),
and an ephemeris appear on MPEC 2017-G05.

                    Epoch = 2016 June 21.0 TT
     T = 2016 June 10.8909 TT         Peri. = 306.8015
     e = 0.995591                     Node  = 206.1937  2000.0
     q = 1.784191 AU                  Incl. = 122.6332


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2017 CBAT
2017 April 2                     (CBET 4379)              Daniel W. E. Green