Luminous Type II Short-Plateau Supernova 2023ufx: Evidence for Asymmetric Explosion and a Partially-Stripped Massive Progenitor

Core Concepts

SN 2023ufx is a unique Type IIP supernova characterized by an exceptionally short plateau duration, suggesting an asymmetric explosion of a partially-stripped massive progenitor star.

Abstract

• Bibliographic Information: Ravi, A. P., Valenti, S., Dong, Y., Hiramatsu, D., Barmentloo, S., Jerkstrand, A., ... & Guti´errez, C. P. (2024). Luminous Type II Short-Plateau SN 2023ufx: Asymmetric Explosion of a Partially-Stripped Massive Progenitor. arXiv preprint arXiv:2411.02493v1.
• Research Objective: To analyze the observational characteristics of supernova SN 2023ufx, a Type IIP supernova with an unusually short plateau duration, to understand its progenitor properties and explosion mechanism.
• Methodology: The researchers analyzed optical and near-infrared photometric and spectroscopic data of SN 2023ufx obtained from various telescopes. They compared the observed data with hydrodynamic and spectral models to constrain the progenitor's mass, explosion energy, and other physical parameters.
• Key Findings:
  • SN 2023ufx exhibited the shortest known plateau duration (tPT ∼ 47 days) for a Type IIP supernova.
  • The supernova had a luminous V-band peak (MV = −18.42 ± 0.08 mag) and a rapid early decline rate (s1 = 3.47 ± 0.09 mag (50 days)−1).
  • Comparisons with hydrodynamic models suggested a massive progenitor star with a zero-age main sequence mass (MZAMS) of approximately 19–25 solar masses (M⊙).
  • The short plateau duration indicated a small hydrogen envelope (MHenv ≃ 1.2 M⊙), suggesting partial stripping of the progenitor star's outer layers before the explosion.
  • Nebular spectral analysis revealed broad and multi-peak profiles of certain emission lines, suggesting an asymmetric explosion.
• Main Conclusions: SN 2023ufx provides evidence for the existence of Type IIP supernovae arising from the explosion of partially-stripped massive stars. The short plateau duration and asymmetric explosion geometry suggest a complex and energetic explosion mechanism.
• Significance: This study contributes to our understanding of the diversity of Type IIP supernovae and the late stages of massive star evolution. The findings have implications for models of stellar mass loss, explosion mechanisms, and the production of heavy elements in supernovae.
• Limitations and Future Research: The study acknowledges the limitations of relying on a single well-observed event. Further observations and modeling of similar short-plateau supernovae are needed to confirm the findings and refine our understanding of this subclass of Type IIP supernovae.

Stats

SN 2023ufx has a plateau duration of approximately 47 days.
The peak V-band magnitude of SN 2023ufx is -18.42 ± 0.08 mag.
The estimated mass of nickel (56Ni) produced during the explosion is ∼0.14 ± 0.02 M⊙.
The progenitor star is estimated to have had a zero-age main sequence mass of approximately 19–25 M⊙.
The hydrogen envelope mass at the time of explosion is estimated to be ∼1.2 M⊙.

Quotes

"SN 2023ufx [is] a unique Type IIP SN with the shortest known plateau duration (tPT ∼ 47 days)"
"For a Type IIP, SN 2023ufx produced an unusually high amount of nickel (56Ni) ∼ 0.14 ± 0.02 M⊙, during the explosion."
"Nebular line diagnostics [...] suggest that the explosion of SN 2023ufx could be inherently asymmetric, preferentially ejecting material along our line-of-sight."

Key Insights Distilled From

Luminous Type II Short-Plateau SN 2023ufx: Asymmetric Explosion of a Partially-Stripped Massive Progenitor

by Aravind P. R... at arxiv.org 11-06-2024

https://arxiv.org/pdf/2411.02493.pdf

Deeper Inquiries

How do the properties and evolution of SN 2023ufx compare to other known Type IIP supernovae with short plateau durations?

SN 2023ufx stands out even among the rare class of short-plateau Type IIP supernovae (SPSNe). Here's a comparative breakdown:

Plateau Duration (tPT): With a tPT of ~47 days, SN 2023ufx has the shortest plateau observed to date. Other SPSNe typically exhibit plateaus of ~50-70 days. This extreme brevity strongly suggests a significantly reduced hydrogen envelope.

Peak Luminosity: SN 2023ufx is exceptionally luminous, reaching an absolute V-band magnitude (MV) of -18.42. This places it among the most luminous SPSNe, such as SN 2006Y and SN 2016egz.

Early Decline Rate (s1): The light curve exhibits an unusually rapid early decline, with s1 = 3.47 mag/(50 days). This rapid decline, coupled with high luminosity, is atypical for SNe IIP and further supports the scenario of a progenitor star with a small hydrogen envelope.

Nickel-56 Mass (MNi): SN 2023ufx exhibits a high MNi of ~0.14 solar masses, consistent with other luminous SPSNe. This suggests a massive progenitor star, as more massive stars produce more nickel during their explosive deaths.

Spectroscopic Evolution: The early spectra of SN 2023ufx are relatively featureless, similar to other luminous SPSNe. The later emergence of Balmer lines and the low absorption-to-emission ratio in Hα are also consistent with this subclass.
In summary: SN 2023ufx pushes the boundaries of known SPSNe properties with its record-breaking short plateau and high luminosity. These characteristics, combined with its rapid early decline and high nickel mass, strongly favor a partially-stripped massive progenitor star as the origin.

Could alternative mechanisms, such as interaction with a binary companion, explain the observed properties of SN 2023ufx instead of a partially-stripped massive progenitor?

While a partially-stripped massive progenitor is the leading explanation for SN 2023ufx's unique properties, it's essential to consider alternative scenarios, such as binary interaction:
Binary Interaction Scenario:

Common Envelope Evolution: A massive star in a close binary system could have its hydrogen envelope stripped through interaction with a companion, leading to a short plateau.
Mass Transfer: Material could be transferred from the progenitor to the companion, potentially altering the progenitor's evolution and leading to a smaller hydrogen envelope at the time of explosion.
Challenges for the Binary Scenario:

Lack of Direct Evidence: No direct observational evidence for a binary companion has been found yet.
High Luminosity: Explaining the high luminosity solely through binary interaction might be challenging.
High Nickel Mass: The high MNi is more naturally explained by a massive progenitor, as binary interaction might not significantly enhance nickel production.
Partially-Stripped Progenitor vs. Binary Interaction:

Current Evidence Favors Partially-Stripped Progenitor: The combination of high luminosity, short plateau, rapid decline, and high MNi aligns well with theoretical models of partially-stripped massive stars.
Binary Interaction Cannot Be Ruled Out: Further observations, such as late-time imaging to search for a surviving companion, are needed to definitively confirm or rule out binary interaction.
In conclusion: While a partially-stripped massive progenitor is the more likely explanation based on current data, the possibility of binary interaction cannot be entirely dismissed without further investigation.

What are the implications of discovering a supernova with such a short plateau duration for our understanding of the diversity of stellar death and the evolution of galaxies?

The discovery of SN 2023ufx, with its exceptionally short plateau, has significant implications for our understanding of stellar evolution and its broader impact:
Diversity of Stellar Death:

Expanding the Parameter Space: SN 2023ufx demonstrates that the diversity of Type IIP supernovae is even greater than previously thought, pushing the boundaries of observed plateau durations.
Constraints on Stellar Evolution Models: Such an extreme case provides crucial observational constraints for refining stellar evolution models, particularly those dealing with mass loss in massive stars and the late stages of their lives.
Probing the RSG Problem: The high mass inferred for the progenitor of SN 2023ufx could provide insights into the "red supergiant problem," which questions why we observe fewer high-mass supernova progenitors than models predict.
Evolution of Galaxies:

Chemical Enrichment: The high MNi in SN 2023ufx implies a significant contribution of heavy elements to the interstellar medium, influencing the chemical evolution of its host galaxy.
Understanding Star Formation History: The presence of such a massive progenitor in a low-metallicity galaxy like the host of SN 2023ufx provides clues about the star formation history and chemical enrichment processes in such environments.
Future Directions:

Finding More SPSNe: Discovering and studying more SPSNe is crucial to understanding their origins and refining our knowledge of massive star evolution.
Late-Time Observations: Continued monitoring of SN 2023ufx, particularly at late times, could reveal the presence of a binary companion or provide further insights into the explosion mechanism.
In conclusion: SN 2023ufx highlights the remarkable diversity of stellar deaths and provides valuable data for refining our understanding of massive star evolution, nucleosynthesis, and the impact of supernovae on the evolution of galaxies.