[Iaude] CBET 4595: 20190108 : COMET P/2019 A2 (ATLAS)

quai at eps.harvard.edu quai at eps.harvard.edu
Tue Jan 8 12:22:58 EST 2019

                                                  Electronic Telegram No. 4595
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

     A. Fitzsimmons has reported the discovery of a comet on exposures made on
Jan. 4 UT with a 0.5-m reflector at Haleakala in the course of the "Asteroid
Terrestrial-Impact Last Alert System" (ATLAS) search program (discovery
observations tabulated below); four 30-s exposures show a 15" tail in p.a.
275 degrees.

     2019 UT             R.A. (2000) Decl.       Mag.
     Jan.  4.48478    7 42 25.19   +11 40 41.2   18.7
           4.49908    7 42 24.66   +11 40 45.6   18.9
           4.50565    7 42 24.43   +11 40 47.2   18.7
           4.51883    7 42 23.95   +11 40 50.2   18.9

After the object was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists also commented on the cometary appearance.  H. Sato, Tokyo,
Japan, writes that seven stacked 60-s exposures taken with an iTelescope
0.43-m f/6.8 astrograph near Mayhill, NM, USA, on Jan. 5.20 UT show a strongly
condensed coma of size 8" x 10" with a tail 20" long toward p.a. 275 degrees;
the magnitude was 18.7 as measured within a circular aperture of radius 7".6.
Y. Ramanjooloo and S. Thompson obtained three exposures on Jan. 5.43 with the
University of Hawaii 2.2-m telescope at Mauna Kea that show an obvious dust
tail extending for at least 30" towards p.a. 280 deg; the comet's had shows a
full-width-at-half-maximum of 1".8 (vs. 1".3 for nearby stars).  Co-added
20-s exposures taken by P. Bacci and M. Maestripieri with a 0.6-m reflector
at San Marcello Pistoiese, Italy, on Jan. 5.9 (measured by Bacci, L. Tesi, and
G. Fagioli) show a diffuse object.  Stacked images taken by A. Maury, J.-B. de
Vanssay, and J.-G. Bosch with a 0.4-m f/5 Ritchey-Chretien reflector on Jan.
6.3 at San Pedro de Atacama, Chile, show a coma around 15" in size (red mag
17.2-17.8) with a possible tail 9" long in p.a. 20 deg.  Twelve stacked 120-s
unfiltered images taken by G. Favero and R. Furgoni with a 0.80-m f/4
reflector at Castello Tesino, Italy, on Jan. 7.9 show an apparent elongation
and a clear tail about 30" long in p.a. 300 deg; the red mag was reported as
17.7-17.8.  J.-F. Soulier, Dauban, France, writes that sixty 60-s unfiltered
images taken with a 0.20-m f/4 Newtonian reflector on Jan. 8.0 show a 12" coma
and a tail about 25" long in p.a. 275 deg; the red magnitude was 18.6 in a
photometric aperture of radius 6".6.
     The available astrometry (including pre-discovery observations made with
the Purple Mountain Observatory 1.04-m Schmidt telescope on 2018 Dec. 13.8 UT,
when the red magnitude was given as 18.4-18.6; with the ATLAS discovery
telescope on Dec. 27.5, when the V magnitude was gien as 17.8-18.8; and by
M. Ory with a 0.5-m reflector at the Oukaimeden Observatory, Marrakech,
when the magnitude was given as 18.2-18.7), the following elliptical orbital
elements by G. V. Williams (from 83 observations spanning 2018 Dec. 13-2019
Jan. 8), and an ephemeris appear on MPEC 2019-A126.

                    Epoch = 2018 Nov. 18.0 TT
     T = 2018 Dec.  1.2114 TT         Peri. = 326.0825
     e = 0.377928                     Node  = 139.3344  2000.0
     q = 3.554250 AU                  Incl. =  14.9324
       a =  5.713568 AU    n = 0.0721677    P =  13.66 years

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

                         (C) Copyright 2019 CBAT
2019 January 8                   (CBET 4595)              Daniel W. E. Green

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