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 ∼1043 erg 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.

中文翻译：

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SN2023fyq：由于双星相互作用而具有长期前驱体活性的 Ibn 型超新星


我们展示了对 SN 2023fyq 的光度和光谱观测，SN 2023fyq 是附近星系 NGC 4388 （D ≃ 18 Mpc） 中的一颗 Ibn 型超新星 （SN）。此外，我们使用来自 DLT40、ATLAS、Zwicky Transient Facility、ASAS-SN、Swift 和业余天文学家 Koichi Itagaki 的数据追踪了 SN 2023fyq 位置长达 3 年的前体发射。双峰爆炸后光曲线达到 ∼1043 erg s-1 的光度。在星云光谱中观察到的强中宽 He 线意味着相互作用在后期仍然活跃。我们发现，SN 2023fyq 中的前驱体活动最好地用涉及低质量 He 星和致密伴星的双星系统中的质量传递来解释。在此过程中可能形成赤道盘 （∼0.6M⊙），SN 喷射物与该盘的相互作用为 SN 的第二个峰提供动力。早期的 SN 光曲线显示，在 SN 爆炸前几周，在 ∼3000R⊙ 处存在致密的延伸物质 （∼0.3M⊙），这可能是由于最后阶段的核硅燃烧或双星轨道收缩导致失控的传质，导致前驱体发射在爆炸前 ∼30 天内迅速上升。最终的爆炸可能是由 He 星的核心坍缩或 He 星与致密物体的合并引发的。SN 2023fyq 与 SN 2018gjx 和 SN 2015G 一起构成了一类独特的 Ibn SNe 型，它起源于双星系统，并可能表现出可探测的持久爆炸前爆发，震级范围为 -10 到 -13。