Combined special issue of the 6th Workshop on Stochasticity in Fusion Plasmas and the 531st Wilhelm and Else Hereaus Seminar on '3D versus 2D in Hot Plasmas'

[摘要] We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during itsremarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip light curve,corresponding to its initial brightening in August (2012-A) and its dramatic rebrightening in early October(2012-B). Based on line fluxes and velocities measured in our spectra, we find a surprisingly low I (Hα)/I (Hβ)ratio (∼1.3–1.4) in the 2012-B spectra. Such a ratio implies either a rare Case B recombination scenario whereHα, but not Hβ, is optically thick, or an extremely high density for the circumstellar material of ne > 1013 cm−3.The Hα line intensity yields a minimum radiating surface area of 20,000 AU2 in Hα at the peak of SN 2009ip’sphotometric evolution. Combined with the nature of this object’s spectral evolution in 2012, a high circumstellardensity and large radiating surface area imply the presence of a thin disk geometry around the central star (and,consequently, a possible binary companion), suggesting that the observed 2012-B rebrightening of SN 2009ip canbe attributed to the illumination of the disk’s inner rim by fast-moving ejecta produced by the underlying events of2012-A.

[关键词] circumstellar matter;stars: massive;stars: variables: general;supernovae: general