2024ApJ...969...32S

We study the energy sources, the physical properties of the ejecta and the circumstellar medium (CSM), and the mass-loss history of the progenitor of SN 2017dio, which is a broad-lined Ic (Ic-BL) supernova (SN) having unusual light curves (LCs) and signatures of hydrogen-rich CSM in its early spectrum. We find that the temperature of SN 2017dio began to increase linearly about 20 days after the explosion. We use the ⁵⁶Ni plus the ejecta-CSM interaction model to fit the LCs of SN 2017dio, finding that the masses of the ejecta, the ⁵⁶Ni, and the CSM are ∼12.41 M_⊙, ∼0.17 M_⊙, and ∼5.82 M_⊙, respectively. The early-time photosphere velocity and the kinetic energy of the SN are, respectively, ∼1.89 × 10⁴ km s^–1 and ∼2.66 × 10⁵² erg, which are comparable to those of SNe Ic-BL and hypernovae (HNe), respectively. We suggest that the CSM of SN 2017dio might be from a luminous blue variable-like outburst or pulsational pair instability ∼1.2-11.4 yr prior to the SN explosion or binary mass transfer. Moreover, we find that its ejecta mass is larger than those of many SNe Ic-BL and that its ⁵⁶Ni mass (M_Ni) is approximately equal to the mean (or median) value of M_Ni of SNe Ic-BL in the literature but lower than M_Ni of prototype HNe (e.g., SN 1998bw and SN 2003dh).