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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.12343 |
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| _version_ | 1866911324766732288 |
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| author | Xi, Qiang Sun, Ning-Chen Aguado, David P'erez-Fournon, Ismael Poidevin, Fr'ed'erick Jin, Junjie Mao, Yiming Niu, Zexi Wang, Beichuan Zhang, Yu Misra, Kuntal Janghel, Divyanshu Maund, Justyn R. Kumar, Amit Tinyanont, Samaporn Liu, Liang-Duan Zhang, Yu-Hao Ailawadhi, Bhavya Dubey, Monalisa Guo, Zhen Gupta, Anshika He, Min Jain, Dhruv Kar, Debalina Li, Wenxiong Lyman, Joe D. Mu, Haiyang Pranshu, Kumar Sun, Xinxiang Wang, Lingzhi Yadav, Sarvesh Kumar Zhao, Yi-Han Zheng, Jie Zhu, Yinan Fern'andez-Nespral, David L'opez Oramas, Alicia L'opez Wang, Yanan Wiersema, Klaas Liu, Jifeng |
| author_facet | Xi, Qiang Sun, Ning-Chen Aguado, David P'erez-Fournon, Ismael Poidevin, Fr'ed'erick Jin, Junjie Mao, Yiming Niu, Zexi Wang, Beichuan Zhang, Yu Misra, Kuntal Janghel, Divyanshu Maund, Justyn R. Kumar, Amit Tinyanont, Samaporn Liu, Liang-Duan Zhang, Yu-Hao Ailawadhi, Bhavya Dubey, Monalisa Guo, Zhen Gupta, Anshika He, Min Jain, Dhruv Kar, Debalina Li, Wenxiong Lyman, Joe D. Mu, Haiyang Pranshu, Kumar Sun, Xinxiang Wang, Lingzhi Yadav, Sarvesh Kumar Zhao, Yi-Han Zheng, Jie Zhu, Yinan Fern'andez-Nespral, David L'opez Oramas, Alicia L'opez Wang, Yanan Wiersema, Klaas Liu, Jifeng |
| contents | SN 2024aecx is a nearby ($\sim$11 Mpc) Type IIb SN discovered within $\sim$1 d after explosion. In this paper we report high-cadence photometric (typically 0.5$\sim$1 day) and spectroscopic follow-up observations, conducted from as early as 0.27 d post discovery out to the nebular phase at 158.4 d. We analyze the environment of SN 2024aecx and derive a new distance (11.3$\pm$1.1 Mpc), metallicity and host extinction. The light curve exhibits a hot and luminous shock-cooling peak at the first few days, followed by a main peak with very rapid post-maximum decline. The earliest spectra are blue and featureless, while from 2.3 d after discovery prominent P-Cygni profiles emerge. At nebular phase, the emission lines exhibit asymmetric and double-peaked profiles, indicating asphericity and/or early dust formation in the ejecta. Nebular spectral modelling indicates a blueshifted O-rich clump moving toward observer, and the $[\text{OI}]/[\text{CaII}]$ line ratio suggests an intermediate-mass progenitor. We simulated the progenitor and explosion using a two-component model of shock cooling and radioactive $^{56}$Ni heating; our model favors an extended, low-mass H-rich envelope with $M_{\mathrm{e}} = 0.04\pm{0.01} M_{\odot}$ and a low ejecta mass of$M_{\mathrm{ej}} = 1.55^{+0.18}_{-0.14} M_{\odot}$. And the nebular-phase spectra and light-curve modelling both suggest that it most likely originated from an intermediate-mass binary progenitor system. The comprehensive monitoring of SN 2024aecx, coupled with the detailed characterization of its local environment, establishes it as a benchmark event for probing the progenitors and explosion mechanisms of Type IIb SNe. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_12343 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | SN 2024aecx: a fast-evolving Type IIb supernova with a prominent shock-cooling peak Xi, Qiang Sun, Ning-Chen Aguado, David P'erez-Fournon, Ismael Poidevin, Fr'ed'erick Jin, Junjie Mao, Yiming Niu, Zexi Wang, Beichuan Zhang, Yu Misra, Kuntal Janghel, Divyanshu Maund, Justyn R. Kumar, Amit Tinyanont, Samaporn Liu, Liang-Duan Zhang, Yu-Hao Ailawadhi, Bhavya Dubey, Monalisa Guo, Zhen Gupta, Anshika He, Min Jain, Dhruv Kar, Debalina Li, Wenxiong Lyman, Joe D. Mu, Haiyang Pranshu, Kumar Sun, Xinxiang Wang, Lingzhi Yadav, Sarvesh Kumar Zhao, Yi-Han Zheng, Jie Zhu, Yinan Fern'andez-Nespral, David L'opez Oramas, Alicia L'opez Wang, Yanan Wiersema, Klaas Liu, Jifeng Solar and Stellar Astrophysics High Energy Astrophysical Phenomena SN 2024aecx is a nearby ($\sim$11 Mpc) Type IIb SN discovered within $\sim$1 d after explosion. In this paper we report high-cadence photometric (typically 0.5$\sim$1 day) and spectroscopic follow-up observations, conducted from as early as 0.27 d post discovery out to the nebular phase at 158.4 d. We analyze the environment of SN 2024aecx and derive a new distance (11.3$\pm$1.1 Mpc), metallicity and host extinction. The light curve exhibits a hot and luminous shock-cooling peak at the first few days, followed by a main peak with very rapid post-maximum decline. The earliest spectra are blue and featureless, while from 2.3 d after discovery prominent P-Cygni profiles emerge. At nebular phase, the emission lines exhibit asymmetric and double-peaked profiles, indicating asphericity and/or early dust formation in the ejecta. Nebular spectral modelling indicates a blueshifted O-rich clump moving toward observer, and the $[\text{OI}]/[\text{CaII}]$ line ratio suggests an intermediate-mass progenitor. We simulated the progenitor and explosion using a two-component model of shock cooling and radioactive $^{56}$Ni heating; our model favors an extended, low-mass H-rich envelope with $M_{\mathrm{e}} = 0.04\pm{0.01} M_{\odot}$ and a low ejecta mass of$M_{\mathrm{ej}} = 1.55^{+0.18}_{-0.14} M_{\odot}$. And the nebular-phase spectra and light-curve modelling both suggest that it most likely originated from an intermediate-mass binary progenitor system. The comprehensive monitoring of SN 2024aecx, coupled with the detailed characterization of its local environment, establishes it as a benchmark event for probing the progenitors and explosion mechanisms of Type IIb SNe. |
| title | SN 2024aecx: a fast-evolving Type IIb supernova with a prominent shock-cooling peak |
| topic | Solar and Stellar Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2509.12343 |