Rapidly-Declining Hostless Type Ia Supernova KSP-OT-201509b from the KMTNet Supernova Program: Transitional Nature and Constraint on ${}^{56}$Ni Distribution and Progenitor Type

Dae-Sik Moon, Yuan Qi Ni, Maria R. Drout +8

We report the early discovery and multi-color ($BVI$) high-cadence light curve analyses of a rapidly-declining sub-Chandrasekhar Type Ia supernova KSP-OT-201509b (= AT2015cx) from…