paper

Late-time evolution of the interacting stripped-envelope supernova 2017dio

arXiv:2606.28918 · doi:10.1051/0004-6361/202659538

Abstract

The discovery of stripped-envelope supernovae (SNe) interacting with dense circumstellar medium (CSM) challenges our current understanding of massive star evolution. We present late-time observations of the interacting Type Ic SN 2017dio and investigate its mass-loss mechanism and progenitor channel. We analysed late-time spectra and light curves (LCs) that are dominated by ejecta-CSM interaction. We examined the CSM and the source of the infrared (IR) excess by modelling the radiation produced by the ejecta-CSM interaction and the IR echo from circumstellar dust. In addition, we studied the evolution of spectral features, with a particular emphasis on the Halpha emission line. From the combined analysis of the LCs and spectral properties, we infer that the peak mass-loss rate for the CSM reaches ~0.2 and that the typical value over most epochs is ~0.06 . The nearby CSM was formed over a period of 4 to 65 years before the explosion. The CSM radius begins at ~ cm. The IR excess identified in the LCs is consistent with the radiation from dust with a mass increasing from ~0.001 to ~0.005 in the case of carbon dust or ~0.005 to ~0.02 in the case of silicate dust. From IR echo modelling, we estimate an upper limit on the dust mass of , which implies an SN progenitor mass-loss rate of at the dust evaporation radius determined by the SN peak luminosity (0.017 pc for carbon dust, corresponding to mass loss ~170 years before the explosion). This implies a very rapid increase in the mass-loss rate ahead of the explosion. Although the progenitor of SN 2017dio has lost its helium envelope, it interacted with a hydrogen-rich CSM formed shortly before the explosion, suggesting that this material originated from a companion star rather than the progenitor itself. [Abridged]

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