Letter to the Editor

SN 2022jli modeled with a ⁵⁶Ni double layer and a magnetar

¹ Laboratorio de Investigación Científica en Astronomía, UNRN, Sede Andina, Mitre 630 (8400), Bariloche, Argentina
² Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, Buenos Aires, Argentina
³ Instituto de Astrofísica de La Plata (IALP), CCT-CONICET-UNLP, Paseo del Bosque s/n, B1900FWA La Plata, Argentina
⁴ Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque s/n, 1900 La Plata, Buenos Aires, Argentina
⁵ Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
⁶ Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860 Castelldefels, (Barcelona), Spain
⁷ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain

^⋆ Corresponding author: morellana@unrn.edu.ar

Received: 27 April 2025
Accepted: 25 July 2025

Abstract

Context. We study the bolometric evolution of the exceptional Type Ic supernova SN 2022jli, aiming to understand the underlying mechanisms responsible for its distinctive double-peaked light curve morphology, extended timescales, and the rapid, steep decline in luminosity observed at around 270 days after the SN discovery.

Aims. We present a quantitative assessment of two leading models through the use of hydrodynamic radiative simulations: two shells enriched with nickel and a combination of nickel and magnetar power.

Methods. We explored the parameter space of a model in which the supernova (SN) is powered by radioactive decay while assuming a bimodal nickel distribution. Though this setup can reproduce the early light curve properties, it faces problems explaining the prominent second peak. We therefore considered a hybrid scenario with a rapidly rotating magnetar as an additional energy source.

Results. We find that the observed light curve morphology can be well reproduced by a model combining a magnetar engine and a double-layer ⁵⁶Ni distribution. The best-fitting case consists of a magnetar with a spin period of P ≃ 22 ms and a bipolar magnetic field strength of B ≃ 5 × 10¹⁴ G and a radioactive content with a total M(⁵⁶Ni) of 0.15 M_⊙ distributed across two distinct shells within a pre-SN structure of 11 M_⊙. To reproduce the abrupt drop in luminosity at ∼270 d, the energy deposition from the magnetar must be rapidly and effectively switched off.