WFST Supernovae in the First Year. II. SN 2024aedt: Systematical Study of a Transitional Type Ia Supernova - UTU Research Portal

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WFST Supernovae in the First Year. II. SN 2024aedt: Systematical Study of a Transitional Type Ia Supernova

Authors: Meng, Dezheng; Jiang, Ji-an; Kong, Xu; Xu, Zelin; Maeda, Keiichi; Kuncarayakti, Hanindyo; Galbany, Lluis; Jha, Saurabh W.; Ivezic, Zeljko; Yoachim, Peter; Wu, Weiyu; Liu, Zhengyan; Zhao, Junhan; Connolly, Andrew J.; Jia, Ziqing; Hu, Lei; Ding, Weiyu; Fan, Lulu; Li, Feng; Liang, Ming; Tang, Jinlong; Wan, Zhen; Wang, Hairen; Wang, Jian; Xue, Yongquan; Zhang, Hongfei; Zhao, Wen; Zheng, Xianzhong; Zhu, Qingfeng

Publication year: 2026

Journal: Astrophysical Journal

Article number: 54

Volume: 1002

Issue: 1

ISSN: 0004-637X

eISSN: 1538-4357

DOI: https://doi.org/10.3847/1538-4357/ae4c87

Publication's open availability at the time of reporting: Open Access

Publication channel's open availability : Open Access publication channel

Web address : https://iopscience.iop.org/article/10.3847/1538-4357/ae4c87

Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/523310202

Self-archived copy's licence: CC BY

Self-archived copy's version: Publisher`s PDF

Abstract

We present comprehensive photometric and spectroscopic observations of a transitional Type Ia supernova (SN Ia), SN 2024aedt, discovered by the 2.5 m Wide Field Survey Telescope within 1 day of the explosion. Its light curve is characterized by a peak absolute magnitude of M_B = −18.49 ± 0.03 mag and a decline rate of Δm₁₅(B) = 1.53 ± 0.36 mag, placing the object on the Δm₁₅(B)–M_B diagram in the transition region between normal and subluminous SNe Ia. Furthermore, the early color evolution and host galaxy environment of SN 2024aedt underscore its transitional nature, sharing properties with both normal and SN 1991bg–like SNe Ia. Light-curve modeling with MOSFiT yields a synthesized ⁵⁶Ni mass of 0.414 ± 0.042 M_⊙and a total ejecta mass of 0.548 ± 0.108 M_⊙. A comparison with theoretical models suggests that the evolutionary trend can be broadly explained by both delayed-detonation and double-detonation (DDet) scenarios, while possible early-excess emissions predicted by DDet cannot be identified given the limited detections soon after the SN explosion. Although the overall spectral evolution of SN 2024aedt is similar to that of other transitional SNe Ia, the spectroscopic comparison reveals diversity in the early-phase blue-end features, which becomes more homogeneous at later phases. This result indicates the importance of early-time observations in understanding the origin of SN Ia diversity.

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Funding information in the publication:
This work was supported by the National Key R&D Program of China (grant No. 2023YFA1608100), the National Natural Science Foundation of China (grant No. 12393811, 12233008), and the Strategic Priority Research Program of the Chinese Academy of Science (grant No. XDB0550300). J.J. acknowledges support from the Japan Society for the Promotion of Science (JSPS) KAKENHI grants JP22K14069. K.M. acknowledges support from JSPS KAKENHI grants JP24KK0070 and 24H01810. K.M. and H.K. acknowledge support from the JSPS bilateral JPJSBP120229923. L.G. acknowledges financial support from AGAUR, CSIC, MCIN, and AEI 10.13039/501100011033 under projects PID2023-151307NB-I00, PIE 20215AT016, CEX2020-001058-M, ILINK23001, COOPB2304, and 2021-SGR-01270.