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| Main Authors: | , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2512.03531 |
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| _version_ | 1866912745888153600 |
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| author | Meng, Xiang-Cun Podsiadlowski, Philipp |
| author_facet | Meng, Xiang-Cun Podsiadlowski, Philipp |
| contents | SN 2020eyj is the first type Ia supernova (SN Ia) showing the signature of a compact helium-rich circumstellar material (CSM). Such a large CSM is difficult to explain in a single-degenerate scenario where the donor star is a helium star. Here we show that, under certain conditions, it is possible that the transfer of helium leads to a common envelope (CE) engulfing the system, similar to the common-envelope wind model proposed by Meng \& Podsiadlowski (2017). If in such a helium common-envelope wind (HeCEW) model the initial white dwarf (WD) mass is larger than 1.1 $M_{\rm \odot}$ and the helium star more massive than 1.8 $M_{\rm \odot}$, the mass of a helium CE can be larger than 0.3 $M_{\rm \odot}$ prior to supernova explosion. The CE mass heavily depends on the initial parameters of the binary system. A dynamical CE ejection event could occur shortly before the supernova, and then our model may naturally explain the properties of SN 2020eyj, specifically the massive He-rich CSM, its dim peak brightness, low ejecta velocity and low birth rate. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_03531 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The helium common-envelope wind scenario for SN 2020eyj Meng, Xiang-Cun Podsiadlowski, Philipp High Energy Astrophysical Phenomena Solar and Stellar Astrophysics SN 2020eyj is the first type Ia supernova (SN Ia) showing the signature of a compact helium-rich circumstellar material (CSM). Such a large CSM is difficult to explain in a single-degenerate scenario where the donor star is a helium star. Here we show that, under certain conditions, it is possible that the transfer of helium leads to a common envelope (CE) engulfing the system, similar to the common-envelope wind model proposed by Meng \& Podsiadlowski (2017). If in such a helium common-envelope wind (HeCEW) model the initial white dwarf (WD) mass is larger than 1.1 $M_{\rm \odot}$ and the helium star more massive than 1.8 $M_{\rm \odot}$, the mass of a helium CE can be larger than 0.3 $M_{\rm \odot}$ prior to supernova explosion. The CE mass heavily depends on the initial parameters of the binary system. A dynamical CE ejection event could occur shortly before the supernova, and then our model may naturally explain the properties of SN 2020eyj, specifically the massive He-rich CSM, its dim peak brightness, low ejecta velocity and low birth rate. |
| title | The helium common-envelope wind scenario for SN 2020eyj |
| topic | High Energy Astrophysical Phenomena Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2512.03531 |