------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2846 2012 Aug 13 11.59UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- BRIGHTENING OF R71 (= HDE 269006) IN LMC R. Gamen, Instituto de Astrofisica de La Plata and others report on CBET 3192 that the LBV HDE 269006 (= R71) in the LMC continues to brighten visually since their IAUC 9082 report, when it was at magnitude V = 9. Differential photometry from images obtained in 2012 Apr shows that R71 has brightened by 0.6 mag in V since Apr. 2010 and is currently at V approximately 8.3. This unprecedented rise in its light curve is accompanied by spectacular variations in its optical spectrum. In 2009 Aug, it resembled a (peculiar) early-F supergiant, while currently R71 displays early-G supergiant characteristics, on the basis of ionization ratios of absorption lines such as Fe I/Fe II as well as the strength and width of the Ca II H and K absorption lines. Concurrently, H-alpha has transformed from a P-Cyg profile into a centrally reversed, symmetrical broad emission (alternatively, an absorption line with symmetrical emission wings), while the Ca II infrared triplet (849.8-, 854.2-, and 866.2-nm) emission has declined and strong forbidden [Ca II] 729.1- and 732.4-nm emission lines have appeared -- along with weaker ones of [O I-II], [N II], and [S II]. This is the first report of [Ca II] emission in an apparent S Dor event to their knowledge and suggests comparison with the red transients. R71 is previously known to have an unusually strong dust signature in the infrared (Bonanos et al. 2009, A.J. 138, 1003, and references therein). SUPERNOVA 2012dk IN PGC 926 (STUART PARKER) 2012dk Jun 26.60 00 13 56.30 -70 01 40.7 14.4 14 " 19 " Joseph Brimacombe, Australia, reports magnitude 15.7 on June 29. J. T. Parrent: spectrum July 1 type-Ia using Gemini South. It is similar to SN 1990N at three days post-maximum-light. SUPERNOVA 2012dl IN ESO 459-6 (CHASE PROJECT) 2012dl Jun 6.16 19 12 08.21 -32 07 37.0 16.3 7.9"W 1.8"S G. Pignata: spectrum June 23 type-Ia similar to SN 1994D three weeks after maximum light. SUPERNOVA 2012dm (PAN-STARRS) 2012dm Jun 27 14 13 46.13 +52 13 17.3 20.3V The spectrum of 2012dm is best matched by type-Ia supernovae at five days after maximum light. SUPERNOVA 2012dn IN PGC 64605 (STUART PARKER) 2012dn Jly 8.52 20 23 36.26 -28 16 43.4 16.3R 35 "W 3 "S J. T. Parrent: spectrum July 10 type-Ia about a week before maximum light. In addition, the detection of a strong C II 657.8-nm absorption feature (blueshifted by 12200 km/s) and comparisons to pre-maximum spectra of SN 2006gz, SN 2007if and SN 2009dc suggest that 2012dn is a super-Chandra event. Guy Hurst reports that in response to the unusual nature of this event, he has obtained photometry with the Bradford Robotic Telescope. V magnitudes measured are: 2012 July 29.12UT, 14.0; Aug 12.07UT, 14.6. SUPERNOVA 2012do (CSS) 2012do Jun 20.24 13 56 35.28 +04 46 52.3 17.5 L. Tomasella: spectrum July 16 type-Ia similar to several normal type-Ia supernovae at about two weeks after maximum. Guy M Hurst