Electronic Telegram No. 3979 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 COMET C/2011 J2 (LINEAR) F. Manzini, V. Oldani, and A. Dan, Stazione Astronomica di Sozzago, Italy; R. Crippa, Osservatorio di Tradate, Italy; and R. Behrend, Geneva Observatory, report that comet C/2011 J2 (cf. IAUC 9208) was observed with the 0.4-m telescope at Sozzago during about 40 min per night around Aug. 27.95, 28.85, and 30.91 UT. Carefully stacked images show, for both nights, a second, fainter, nuclear condensation located 0".8 east and 7".5 north of the main, brighter nuclear condensation on an image scale of 0".7/pixel. The newly detected condensation was then about 1.5 mag fainter than the brighter one. No relative motion was detected between the two nights. The coma was roughly circular and 50" in diameter, with a 1'-long, faint, diffuse tail visible in p.a. 50 deg. Manzini and Behrend obtained additional exposures with the Sozzago 0.4-m f/6.6 reflector on Sept. 14.0 that show secondary component B to be 2.5 mag fainter than primary component A, with component B located 1".6 east and 9".6 north of component A. Behrend estimates that the date of separation was July 14 +/- 10 days. Numerous other reports of descriptive information from other CCD observers have been received from other observers, with a summary given below. Astrometry of both components have been poublished on MPECs 2014-R69 and 2014-R70, and on MPCs 89407 and 89408. E. Bryssinck, Kruibeke, Belgium, reports that C/2011 J2 was observed with a 0.2-m f/7 refractor (+ Luminance filter) by A. Diepvens (Balen, Belgium) on Aug. 28.88 UT; the stacked images show component B to be 7".5 from component A in p.a. 4 deg. Bryssinck observed the comet on Sept. 2.39 with an iTelescope 0.62-m f/6.5 reflector (+ Luminance filter) at Auberry, CA, USA, showing component B to be 8".9 from component A in p.a. 10 deg (and 1.6-3.0 mag fainter). Bryssinck's images from Sept. 17.02 show component B to be 2.3 mag fainter than component A and 11".3 distant in p.a. 9.6 degrees (0.4-m f/3.8 reflector). L. Buzzi, Varese, Italy, writes that stacked exposures taken with a 0.38-m f/6.8 reflector on Sept. 3.0 UT show component B to be 2.9 mag fainter than component A and offset 0".8 east and 8".5 north; he infers that component B then showed a diffuse coma around 5" wide without a clear central condensation, making astrometry quite difficult. G. Tancredi, D. Lazzaro, T. Rodrigues, and R. Souza report that they observed the comet with the 1-m telescope of the Observatorio Astronomico do Sertao de Itaparica in Brazil during Sept. 3.12-3.14 UT; their stacked images show component B to be 3 mag fainter than component A and located 8".7 away in p.a. 11 deg. Images obtained at the Mirasteilas Observatory at Falera, Switzerland, by J. De Queiroz and R. Behrend with a 0.90-m f/6.7 reflector on Sept. 3.9 and 4.0 show component B to be 2.5 mag fainter than component A and located 0s.16 east and 8".4 north. Observations obtained by E. Frappa (Planetarium de St-Etienne, France), M. Lavayssiere (Observatoire de Dax, France), and R. Behrend (Geneva Observatory) with the 1.05-m f/12.7 reflector at Pic-du-Midi Observatory on Sept. 4.01-4.05 UT show component B to be 2.5 mag fainter than component A. The total coma diameter is more than 90' in thirty stacked 60-s images, and there is no additional fragment visible down to mag 23. Additional images were taken with the same telescope by Frappa et al. on Sept. 5.1, showing component B to be 3.0 mag fainter than component A and located about 1".5 east and 8".6 north of the brighter component. L. Buzzi and S. Foglia stacked eleven 45-s images taken in good seeing (FWHM = 1".0) with the 2.0-m "Faulkes Telescope North" at Haleakala on Sept. 4.4, showing component B to have an R-band magnitude around 20.5 in an aperture of size 1".5; it was about 3.5 mag fainter than component A, was offset 1".5 east and 8".7 north, and showed a diffuse central condensation 2" wide that was surrounded by a coma at least 5" wide. Images obtained by G. Masi and P. L. Catalano (measured by G. Masi and U. Masi) with a 0.43-m f/6.8 reflector at Ceccano, Italy on Sept. 7.8 UT in bright moonlight show component B to be about 2.4 mag fainter than component A with a size of a few arcseconds in stacked images. Additional images taken by G. Masi on Sept. 13.0 and 13.8-13.9 show component B as before, easily visible despite moonlight. Images obtained by P. Bacci (measured by Bacci, L. Tesi, and G. Fagioli) with a 0.60-m f/4 reflector at San Marcello Pistoiese, Italy, on Sept. 14.0 UT show component B at magnitude about 16.5, about 2 mag fainter than component A and offset 9".7 in p.a. 14 deg. J. Carrillo obtained images on Sept. 15.9 UT with a 0.36-m f/5 reflector at Fuensanta de Martos, Spain, that show component B to be 4 mag fainter than component A. Total-magnitude and coma-diameter estimates for component A: Feb. 22.45 UT, 14.0, -- (K. Kadota, Ageo, Japan, 0.25-m reflector + CCD); 28.78, 13.2, 0'.3 (U. Pilz, Leipzig, Germany, 32-cm reflector; visual); May 2.77, 14.1, -- (Kadota); 30.72, 14.4, -- (Kadota); July 28.65, 14.1, -- (Kadota); Aug. 1.03, 13.2, 1'.2 (Pilz); 3.01, 13.5, 0'.93 (M. L. Paradowski, Dabrowa, Poland, 0.30-m reflector; visual); 18.63, 14.0, -- (Kadota). The total brightness has remained fairly close to the prediction in the ICQ's 2014 Comet Handbook, with no obvious large outburst associated with an outburst seen in these data reported to the ICQ and the Central Bureau. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2014 CBAT 2014 September 19 (CBET 3979) Daniel W. E. Green