Electronic Telegram No. 3659
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@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMETS C/2012 V2 (LINEAR) AND C/2013 R1 (LOVEJOY)
     C. Opitom, E. Jehin, J. Manfroid, and M. Gillon, Liege University,
report that they obtained narrowband photometry on Sept. 11 and 12 with the
robotic TRAPPIST 0.6-m telescope at the European Southern Observatory of
comets C/2012 V2 and C/2013 R1.  Both comets display gaseous comae and are now
visible in the morning sky from the southern hemisphere.  The following
production rates (Haser model with Vp = Vd = 1 km/s) were obtained for C/2012
V2 (when r = 1.50 AU, post-perihelion):  log Q(OH) = 28.4; log Q(NH) = 26.4;
log Q(CN) = 25.9; log Q(C_3) = 25.6; log Q(C_2) = 26.2; and Af(rho) at 526.0
nm = 2600 cm at 10000 km.  A set of narrowband photometry was also collected
on the new comet C/2013 R1 (when r = 1.94 AU, pre-perihelion), resulting in
the following production rates:  log Q(OH) = 27.9; log Q(CN) = 25.5; log
Q(C_3) = 24.9; log Q(C_2) = 25.5; and Af(rho) at 526.0 nm = 160 cm.  These
values indicate that both comets have "typical" composition and that C/2013
R1 has a low dust-to-gas ratio.

     Visual total-magnitude and coma-diameter estimates for comet C/2012 V2:
Aug. 9.82 UT, 8.9, 3' (M. Mattiazzo, Swan Hill, Vic., Australia, 25x100
binoculars); 12.80, 8.6, 4' (D. A. J. Seargent, The Entrance, NSW, Australia,
25x100 binoculars); 23.35, 8.7, 3' (W. Souza, Sao Paulo, Brazil, 0.10-m
refractor); 29.35, 9.2, 4' (A. Amorim, Florianopolis, Brazil, 0.18-m
reflector); Sept. 4.77, 8.9, 3' (Seargent); 27.32, 9.1, 2' (Amorim).

     K. Yoshimoto, Yamaguchi, Japan, reports total CCD mag 13.3 and coma
diameter 1'.2 for comet C/2013 R1 on Sept. 19.79 UT.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 September 29                (CBET 3659)              Daniel W. E. Green