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Abstract We present photometric and spectroscopic observations of SN 2023fyq, a Type Ibn supernova (SN) in the nearby galaxy NGC 4388 (D≃ 18 Mpc). In addition, we trace the 3 yr long precursor emission at the position of SN 2023fyq using data from DLT40, ATLAS, Zwicky Transient Facility, ASAS-SN, Swift, and amateur astronomer Koichi Itagaki. The double-peaked postexplosion light curve reaches a luminosity of ∼1043erg s−1. The strong intermediate-width He lines observed in the nebular spectrum imply the interaction is still active at late phases. We found that the precursor activity in SN 2023fyq is best explained by the mass transfer in a binary system involving a low-mass He star and a compact companion. An equatorial disk is likely formed in this process (∼0.6M⊙), and the interaction of SN ejecta with this disk powers the second peak of the SN. The early SN light curve reveals the presence of dense extended material (∼0.3M⊙) at ∼3000R⊙ejected weeks before the SN explosion, likely due to final-stage core silicon burning or runaway mass transfer resulting from binary orbital shrinking, leading to rapid-rising precursor emission within ∼30 days prior to explosion. The final explosion could be triggered either by the core collapse of the He star or by the merger of the He star with a compact object. SN 2023fyq, along with SN 2018gjx and SN 2015G, forms a unique class of Type Ibn SNe, which originate in binary systems and are likely to exhibit detectable long-lasting pre-explosion outbursts with magnitudes ranging from −10 to −13.
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The X-Ray Luminous Type Ibn SN 2022ablq: Estimates of Preexplosion Mass Loss and Constraints on Precursor Emission
Abstract Type Ibn supernovae (SNe Ibn) are rare stellar explosions powered primarily by interaction between the SN ejecta and H-poor, He-rich material lost by their progenitor stars. Multiwavelength observations, particularly in the X-rays, of SNe Ibn constrain their poorly understood progenitor channels and mass-loss mechanisms. Here we present Swift X-ray, ultraviolet, and ground-based optical observations of the Type Ibn SN 2022ablq, only the second SN Ibn with X-ray detections to date. While similar to the prototypical Type Ibn SN 2006jc in the optical, SN 2022ablq is roughly an order of magnitude more luminous in the X-rays, reaching unabsorbed luminositiesLX∼ 4 × 1040erg s−1between 0.2–10 keV. From these X-ray observations we infer time-varying mass-loss rates between 0.05 and 0.5M⊙yr−1peaking 0.5–2 yr before explosion. This complex mass-loss history and circumstellar environment disfavor steady-state winds as the primary progenitor mass-loss mechanism. We also search for precursor emission from alternative mass-loss mechanisms, such as eruptive outbursts, in forced photometry during the 2 yr before explosion. We find no statistically significant detections brighter thanM≈ −14—too shallow to rule out precursor events similar to those observed for other SNe Ibn. Finally, numerical models of the explosion of an ∼15M⊙helium star that undergoes an eruptive outburst ≈1.8 yr before explosion are consistent with the observed bolometric light curve. We conclude that our observations disfavor a Wolf–Rayet star progenitor losing He-rich material via stellar winds and instead favor lower-mass progenitor models, including Roche-lobe overflow in helium stars with compact binary companions or stars that undergo eruptive outbursts during late-stage nucleosynthesis stages.
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- PAR ID:
- 10557252
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 977
- Issue:
- 1
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 2
- Size(s):
- Article No. 2
- Sponsoring Org:
- National Science Foundation
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