Constraints on the Progenitor of SN 2023bee from its Nebular-Phase Spectra

Sophie von Coelln; Qinan Wang; Matthew R. Siebert; Ping Chen; Armin Rest; Luc Dessart; Yossef Zenati; Georgios Dimitriadis; Katie Auchettl; Siyuan Chen; Kyle W. Davis; Thomas de Boer; Ryan J. Foley; Avishay Gal-Yam; Willem B. Hoogendam; Mark E. Huber; Luca Izzo; Charles D. Kilpatrick; Chien-Cheng Lin; Chang Liu; Thomas Bernard Lowe; Gautham Narayan; César Rojas-Bravo; Aidan Sedgewick; Koji Shukawa; Richard J. Wainscoat

arXiv · 2610.25674

Constraints on the Progenitor of SN 2023bee from its Nebular-Phase Spectra

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Abstract

We present late-time photometry (~100-400 days after peak) and nebular-phase optical/NIR spectroscopy (100-360 days) of the Type Ia supernova (SN Ia) SN 2023bee. This SN Ia was observed TESS immediately before and after explosion and showed a relatively weak early excess light-curve feature detected in multiple UV and optical bands. Possible explanations for this early excess feature include interaction between the SN ejecta and a non-degenerate companion, or the decay of radioactive isotopes synthesized near the ejecta surface in a sub-$\text{M}_\text{Ch}$ double-detonation scenario. However, the degeneracies and incompleteness of existing models have so far prevented a definitive conclusion about its progenitor system. Nebular-phase spectra provide a complementary probe of SN Ia progenitors by constraining stripped H/He-rich material and iron-group abundances sensitive to the progenitor white dwarf density. We report the non-detection of narrow H/He features in nebular phase optical/NIR spectra of SN 2023bee, placing upper limits of $m^{\text{stripped}}_\text{H}\lesssim5.0\times10^{-3}\text{ M}_\odot$ and $m_\text{He}^{\text{stripped}}\lesssim1.2\times10^{-4}\text{ M}_\odot$. These limits strongly disfavor a non-degenerate companion and suggest that companion interaction is unlikely to explain the early excess of SN 2023bee. We also performed line-diagnostic measurements on the 7200 Åcomplex using multi-Gaussian fitting and continuum estimation, with the inferred velocities validated against NIR spectrum at the similar phase. The resulting low Ni-to-Fe mass ratio, $m_\text{Ni}/m_\text{Fe}\lesssim 0.06$, is broadly consistent with a sub-$M_{\text{Ch}}$ double-detonation progenitor system.

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Sophie von Coelln, Qinan Wang, Matthew R. Siebert, Ping Chen, Armin Rest, Luc Dessart, Yossef Zenati, Georgios Dimitriadis, Katie Auchettl, Siyuan Chen, Kyle W. Davis, Thomas de Boer, Ryan J. Foley, Avishay Gal-Yam, Willem B. Hoogendam, Mark E. Huber, Luca Izzo, Charles D. Kilpatrick, Chien-Cheng Lin, Chang Liu, Thomas Bernard Lowe, Gautham Narayan, César Rojas-Bravo, Aidan Sedgewick, Koji Shukawa, Richard J. Wainscoat. 2026-10-19. Constraints on the Progenitor of SN 2023bee from its Nebular-Phase Spectra. https://arxiv.org/abs/2610.25674

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