Comet C/2012 S1 (Ison)
Central Bureau Electronic Telegrams, 3719, 1 (2013). Edited by Green, D. W. 
C. Opitom, E. Jehin, J. Manfroid, and M. Gillon, Liege University, report on the detection of a new outburst of comet C/2012 S1 that started between Nov. 18.37 and 19.37 UT, in observations made with the robotic TRAPPIST 0.6-m telescope at the European Southern Observatory at La Silla. In the following 48 hours, the gas- and dust-production rates multiplied by a factor of about five. This is the third outburst detected by the TRAPPIST team after those of Nov. 4 (CBET 3693) and Nov. 13 (CBET 3711). The production rates dropped by a factor of about two during the five nights following the previous outburst (Nov. 13). The new maximum was observed on Nov. 21.37 (r = 0.41 AU, Delta = 0.86 AU), and the following gas-production rates were computed for 10000 km from the comet's nucleus using a Haser Model (V_p = V_d = 1 km/s), and Af(rho) was measured in the blue continuum at 10000 km: Q(OH) = 1.08 (+/- 0.58) x 10**29 molecules/s, Q(CN) = 1.60 (+/- 0.18) x 10**27 molecules/s, Q(C_2) = 2.52 (+/- 0.12) x 10**27 molecules/s, Af(rho) = 5820 +/- 644 cm. Two bright jets perpendicular to the tail were visible, and there is no indication yet of splitting or disruption. Additional visual total-magnitude and coma-diameter estimates (cf. CBET 3711; an asterisk indicates a magnitude that has been corrected for atmospheric extinction): Nov. 15.30 UT, 5.3, 5' (W. Souza, Sao Paulo, Brazil, 10x50 binoculars); 16.22, 5.3, 9' (S. Baroni, Milan, Italy, 20x80 binoculars); 17.22, 5.7, 4' (B. H. Granslo, Roverkollen, Oslo, Norway, 10x50 binoculars; altitude 9 degrees; bright sky); 18.17, 5.4, 2' (Kazimieras Cernis, Vilnius, Zirmunai, Lithuania, 7x50 binoculars; altitude 9 degrees); 18.53, 5.4, 3' (Carl Hergenrother, Tucson, AZ, U.S.A., 10x50 binoculars); 19.18, 5.0*, about 4' (M. L. Paradowski, Lublin, Poland, 7x50 binoculars; twilight; altitude 9 degrees); 19.53, 5.2, 3' (Hergenrother); 20.22, 5.0, -- (J. J. Chambo, Valencia, Spain, 20x60 binoculars; moonlight; altitude 7 degrees); 20.24, 4.6, 2' (Granslo, 8.0-cm refractor; altitude 6 degrees); 20.86, 3.8*, -- (K. Yoshimoto, Yamaguchi, Japan, 8x42 binoculars; altitude 9 degrees); 21.25, 3.8, 2' (J. J. Gonzalez, Salamanca, Spain, 10x50 binoculars; 1.5-deg tail; moonlight); 21.45, 4.0, -- (John E. Bortle, Stormville, NY, U.S.A., 15x70 binoculars; low altitude).