南方基地知识库

Extensive photometric and spectroscopic observations are presented for SN 2014cx, a type IIP supernova (SN) exploding in the nearby galaxy NGC 337. The observations are performed in optical and ultraviolet bands, covering from -20 to +400 days from the peak light. The stringent detection limit from prediscovery images suggests that this supernova was actually detected within about 1 day after explosion. Evolution of the very early-time light curve of SN 2014cx is similar to that predicted from a shock breakout and post-shock cooling decline before reaching the optical peak. Our photometric observations show that SN 2014cx has a plateau duration of similar to 100 days, an absolute V-band magnitude of similar to -16.5 mag at t approximate to 50 days, and a nickel mass of 0.056 +/- 0.008 M-circle dot. The spectral evolution of SN 2014cx resembles that of normal SNe IIP like SN 1999em and SN 2004et, except that it has a slightly higher expansion velocity (similar to 4200 km/ s(-1) at approximate to 50 days). From the cooling curve of photospheric temperature, we derive that the progenitor has a pre-explosion radius of similar to 640 R-circle dot, consistent with those obtained from SNEC modeling (similar to 620 R-circle dot) and hydrodynamical modeling of the observables (similar to 570 R-circle dot). Moreover, the hydrodynamical simulations yield a total explosion energy of similar to 0.4 x 10(51) erg, and an ejected mass of similar to 8 M-circle dot. These results indicate that the immediate progenitor of SN 2014cx is likely a red supergiant star with a mass of similar to 10 M-circle dot.