SN 2009ip shows broad supernova spectral features again

ATel #4479; J. Vinko (U Szeged), J. C. Wheeler, J. M. Silverman (U Texas at Austin), G. H. Marion, D. Milisavljevic, R. Margutti, A. M. Soderberg (CfA, Harvard), R. Fesen (Dartmouth), P. Roming, T. Pritchard (PSU)
on 12 Oct 2012; 17:20 UT
Credential Certification: Jozsef Vinko (vinko@astro.as.utexas.edu)

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Following the spectral evolution of the new Type IIn SN 2009ip (Smith & Mauerhan, ATel #4412, ATel #4427; Brimacombe, ATel #4423; Margutti et al., ATel #4425; Leonard et al., ATel #4430; Burgasser et al., ATel #4431; Prieto et al., ATel #4439; Martin et al., ATel #4445; Gall et al. ATel #4454; Bohlsen, ATel #4477), we obtained another medium-resolution optical spectrum with SALT/RSS (Vinko et al., ATel #4435) on 2012 Oct 11.93 UT. The new spectrum clearly shows emerging broad P Cygni components (~ 9,000 km/s) at the position of H-beta, H-gamma, H-delta and H-epsilon. The strength of the broad components is significantly increasing toward the blue. Weak P Cygni component at the H-alpha line is also detectable, although less prominent. No such broad features are visible at the HeI 5876, 6678 and 7065 A lines yet. The spectrum obtained 2 days ago, on Oct 9.47 UT, by Bohlsen (ATel #4477) showed no such broad components for any of the lines listed above. The new spectrum suggests that the fast-moving ejecta of SN 2009ip is currently breaking out from the CSM envelope expelled during the previous LBV outbursts in 2009-2010 (Berger et al. ATel #2184; Drake et al., ATel #2897). Rapid-cadence follow-up observations at all wavelengths are strongly encouraged.