SN 2026dix: a nearby, transitional Type IIb/Ib supernova consistent with a warm supergiant progenitor
Abstract
Understanding the final evolution stages of (very) massive stars and their explosive outcomes, stripped-envelope supernovae (SESNe), represent a long-term challenge for astrophysics. The latest results support a continuous distribution within the traditional SESN subclasses (IIb, Ib, Ic). The nearby (D ≈ 17.5 Mpc) SN 2026dix seems to be another member of the recently identified group of transitional Type IIb/Ib explosions. A point source is located at the SN position within the uncertainties on multiple pre-explosion {\it HST} images. Together with post-explosion photometry and spectroscopy, it provides a good opportunity to study a rare type of SN in detail. We carried out a thorough comparative light-curve (LC) and spectral analysis of SN 2026dix. We also constructed its bolometric LC and modeled it semi-analytically. In addition, we constructed the spectral energy distribution of the presumed progenitor and compared this to model stellar atmospheres and binary stellar evolution tracks. We infer that SN 2026dix arose from an explosion in an interacting binary system, consistent with the properties of a warm (Teff ≈ 6750−7750 K; spectral type F2 to A7), luminous (log(Lbol/L⊙)≈ 4.9−5.3) supergiant primary and a less luminous, less massive hot dwarf companion. The nature of the identified progenitor closely resembles that of some other known cases of SNe IIb and also well aligns with both the results of our semi-analytical LC modeling and the comparison of the LCs and spectra of SN 2026dix with the output of radiative-transfer models of an exploding star with Mini = 18 M⊙.
Related
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BibTeX
@misc{szalai20262026dix,
title = {{SN 2026dix: a nearby, transitional Type IIb/Ib supernova consistent with a warm supergiant progenitor}},
author = {Tamás Szalai and Schuyler D. Van Dyk and Dominik Bánhidi and Andrea P. Nagy and Réka Könyves-Tóth and Alexei V. Filippenko and Thomas G. Brink and WeiKang Zheng and Imre Barna Bíró and István Csányi and Zsófia Bora and Zsóka Horváth and Ágoston Horti-Dávid and András. P. Joó and Dávid Koller and Levente Kriskovics and Klára Lelkes and Katalin Nagy and Krisztián Sárneczky and Ádám Sódor and Róbert Szakáts and András Pál and József Vinkó},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.21836},
eprint = {2609.21836},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.21836},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - SN 2026dix: a nearby, transitional Type IIb/Ib supernova consistent with a warm supergiant progenitor
AU - Tamás Szalai
AU - Schuyler D. Van Dyk
AU - Dominik Bánhidi
AU - Andrea P. Nagy
AU - Réka Könyves-Tóth
AU - Alexei V. Filippenko
AU - Thomas G. Brink
AU - WeiKang Zheng
AU - Imre Barna Bíró
AU - István Csányi
AU - Zsófia Bora
AU - Zsóka Horváth
AU - Ágoston Horti-Dávid
AU - András. P. Joó
AU - Dávid Koller
AU - Levente Kriskovics
AU - Klára Lelkes
AU - Katalin Nagy
AU - Krisztián Sárneczky
AU - Ádám Sódor
AU - Róbert Szakáts
AU - András Pál
AU - József Vinkó
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.21836
UR - https://arxiv.org/abs/2609.21836
AB - Understanding the final evolution stages of (very) massive stars and their explosive outcomes, stripped-envelope supernovae (SESNe), represent a long-term challenge for astrophysics. The latest results support a continuous distribution within the traditional SESN subclasses (IIb, Ib, Ic). The nearby (D ≈ 17.5 Mpc) SN 2026dix seems to be another member of the recently identified group of transitional Type IIb/Ib explosions. A point source is located at the SN position within the uncertainties on multiple pre-explosion {\it HST} images. Together with post-explosion photometry and spectroscopy, it provides a good opportunity to study a rare type of SN in detail. We carried out a thorough comparative light-curve (LC) and spectral analysis of SN 2026dix. We also constructed its bolometric LC and modeled it semi-analytically. In addition, we constructed the spectral energy distribution of the presumed progenitor and compared this to model stellar atmospheres and binary stellar evolution tracks. We infer that SN 2026dix arose from an explosion in an interacting binary system, consistent with the properties of a warm (T_eff ≈ 6750−7750 K; spectral type F2 to A7), luminous (log(L_bol/L_⊙)≈ 4.9−5.3) supergiant primary and a less luminous, less massive hot dwarf companion. The nature of the identified progenitor closely resembles that of some other known cases of SNe IIb and also well aligns with both the results of our semi-analytical LC modeling and the comparison of the LCs and spectra of SN 2026dix with the output of radiative-transfer models of an exploding star with M_ini = 18 M_⊙.
ER -