The Type Ibn Supernova 2019kbj: Indications for Diversity in Type Ibn Supernova Progenitors

• Published in: The Astrophysical journal Vol. 946; no. 1; pp. 30 - 50
• Main Authors: Ben-Ami, Tom, Arcavi, Iair, Newsome, Megan, Farah, Joseph, Pellegrino, Craig, Terreran, Giacomo, Burke, Jamison, Hosseinzadeh, Griffin, McCully, Curtis, Hiramatsu, Daichi, Gonzalez, Estefania Padilla, Howell, D. Andrew
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.03.2023; IOP Publishing
• Subjects: Astrophysics; Bolometers; Continuum radiation; Core-collapse supernovae; Density; Ejecta; Explosions; Interaction models; Light curve; Massive stars; Mathematical models; Parameters; Physical properties; Power sources; Progenitors (astrophysics); Radioactive decay; Supernova; Supernovae
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/acb432

Type Ibn supernovae (SNe) are a rare class of stellar explosions whose progenitor systems are not yet well determined. We present and analyze observations of the Type Ibn SN 2019kbj, and model its light curve in order to constrain its progenitor and explosion parameters. SN 2019kbj shows roughly constant temperature during the first month after peak, indicating a power source (likely circumstellar material interaction) that keeps the continuum emission hot at ∼15,000 K. Indeed, we find that the radioactive decay of 56 Ni is disfavored as the sole power source of the bolometric light curve. A radioactive decay + circumstellar material (CSM) interaction model, on the other hand, does reproduce the bolometric emission well. The fits prefer a uniform-density CSM shell rather than CSM due to a steady mass-loss wind, similar to what is seen in other Type Ibn SNe. The uniform-density CSM shell model requires ∼0.1 M ⊙ of 56 Ni and ∼1 M ⊙ total ejecta mass to reproduce the light curve. SN 2019kbj differs in this manner from another Type Ibn SN with derived physical parameters, SN 2019uo, for which an order of magnitude lower 56 Ni mass and larger ejecta mass were derived. This points toward a possible diversity in SN Ibn progenitor systems and explosions.