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Supernova 1954J (Variable 12) in NGC 2403 Unmasked

S. D. Van Dyk·A. V. Filippenko·R. Chornock·W. Li·P. Challis
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Abstract

We have confirmed that the precursor star of the unusual Supernova 1954J (also known as Variable 12) in NGC 2403 survived what appears to have been a super-outburst, similar to the 1843 Great Eruption of eta Carinae in the Galaxy. The apparent survivor has changed little in brightness and color over the last eight years, and a Keck spectrum reveals characteristics broadly similar to those of eta Car. This is further suggested by our identification of the actual outburst-surviving star in high-resolution images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. We reveal this ``supernova impostor'' as a highly luminous (M_V^0 ~ -8.0 mag), very massive (M_initial >~ 25 Msun) eruptive star, now surrounded by a dusty (A_V ~ 4 mag) nebula, similar to eta Car's famous Homunculus.

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S. D. Van Dyk, A. V. Filippenko, R. Chornock, W. Li, P. Challis. 2005-03-15. Supernova 1954J (Variable 12) in NGC 2403 Unmasked. https://doi.org/10.1086/430238

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