http://arxiv.org/abs/2003.05795

We propose a wind-driven model for peculiar transients, and apply the model to AT2018cow and iPTF14hls. In the wind-driven model, we assume that a continuous outflow like a stellar wind is injected from a central system. While these transients have different observational properties, this unified model can explain their photometric properties which are not reproduced by a supernova-like instantaneous explosion. Furthermore, the model predicts characteristic spectral features and evolution, which are well in line with those of AT2018cow and iPTF14hls. Despite the different observational properties, the wind model shows that they have some common features; the large mass-loss rates (up to $\sim 20M_{\odot}{\rm ~yr^{-1}}$ for AT2018cow and $\sim 30M_{\odot}{\rm ~yr^{-1}}$ for iPTF14hls), the characteristic radii of $\sim 10^{13}{\rm ~cm}$ for the launch of the wind, and the kinetic energies of $\sim 10^{51}{\rm ~erg}$. It would indicate that both may be related to events involving a red super giant (RSG), in which the RSG envelope is rapidly ejected by an event at a stellar core scale. On the other hand, the main differences are time scales and the total ejected mass. We then suggests that iPTF14hls may represent a dynamical common-envelope evolution induced by massive binary systems ($\sim 50M_{\odot}$ each). AT2018cow may be either a tidal disruption event of a low-mass RSG by a black hole (BH), or a BH-forming failed supernova.

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K. Uno and K. Maeda
Fri, 13 Mar 20
31/53

Comments: 10 pages, 8 figures, submitted to ApJ