[IAUC] CBET 3476: 20130416 : COMET C/2013 G7 (McNAUGHT)
quai en eps.harvard.edu
quai en eps.harvard.edu
Mar Abr 16 13:28:25 ART 2013
Electronic Telegram No. 3476
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET C/2013 G7 (McNAUGHT)
R. H. McNaught reports his discovery of a comet on CCD images taken with
the 0.5-m Uppsala Schmidt telescope at Siding Spring (discovery observations
tabulated below), the object described as slightly diffuse (the appearance
he also noted on follow-up images taken the following night through cirrus
clouds). After it was posted on the Minor Planet Center's NEOCP webpage,
other CCD astrometrists also commented on the object's cometary appearance.
Thirty co-added 30-s images taken by R. Holmes and T. Linder with a 0.41-m
f/11 Ritchey-Chretien reflector at Cerro Tololo on Apr. 14.3 UT show a broad
tail 25".1 long in p.a. 14.2 degrees. J. G. Ries (McDonald Observatory,
2.1-m reflector + i-band filter) writes that the object shows an extended,
diffuse, symmetrical halo about 7" across on images from Apr. 14.4, while
images from Apr. 15.4 show a diffuse coma of diameter approximately 7" with
a hint of a very slight extension to the northeast; additional images from
Apr. 16.4 seem to indicate more development of a short tail toward the
northeast. H. Sato (Tokyo, Japan) notes that two stacked 60-s exposures
taken remotely with a 0.51-m f/6.8 astrograph of the iTelescope Observatory
at Siding Spring on Apr. 14.66 show a strongly condensed coma 10" in diameter
with V-band magnitude 18.4 as measured within a circular aperture of radius
6".5; his stacked follow-up exposures on Apr. 15.4 (taken remotely with a
0.43-m f/6.8 astrograph at the iTelescope Observatory near Mayhill, NM, USA)
show a strongly condensed coma 12" in diameter, slightly elongated toward
the north, with a V-band magnitude of 17.9 as measured within a circular
aperture of radius 7".6. E. Guido (Castellammare di Stabia, Italy) reports
that seventeen stacked 40-s R-band images taken remotely by E. Simpson, N.
Howes, and himself on Apr. 15.44-15.45 with the 2.0-m f/10 "Faulkes Telescope
North" at Haleakala show a compact coma about 6" in diameter. R. Ligustri
(Udine, Italy) finds a coma of diameter about 20" on six 120-s exposures
taken on Apr. 16.6 with a 0.50-m f/4.5 reflector of the iTelescope Observatory
at Siding Spring.
2013 UT R.A. (2000) Decl. Mag. Observer
Apr. 13.64649 15 35 39.41 -14 22 45.2 18.1 McNaught
13.65731 15 35 38.77 -14 22 47.1 17.9 "
13.68967 15 35 36.87 -14 22 53.6 17.9 "
13.79403 15 35 30.80 -14 23 14.5 "
13.79659 15 35 30.63 -14 23 14.8 "
The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2013-H10.
T = 2014 Apr. 20.3498 TT Peri. = 225.3215
Node = 48.4064 2000.0
q = 4.381937 AU Incl. = 104.1123
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2013 CBAT
2013 April 16 (CBET 3476) Daniel W. E. Green
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