Optical Photometry of Type II-P Supernova 2004dj in NGC 2403

Abstract

We present photometric data of the type II-P supernova (SN) 2004dj in NGC 2403. The multicolor light curves cover the SN from $\sim$ 60 to 200 days after explosion, and are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. The light curves show a flat evolution in the middle of the plateau phase, then decline exponentially at the late times, with a rate of 0.10$\pm$0.03 mag (10 days)${}^{-1}$ in most of the filters. In the nebular phase, the spectral energy distribution (SED) of SN 2004dj shows a steady increase in the flux near 6600 Åand 8500 Å, which may correspond to the emission lines of H$\alpha$ and Ca II near-IR triplet, respectively. The photometric behavior suggests that SN 2004dj is a normal SN II-P. Compared with the light curves of another typical SN II-P 1999em, we estimate the explosion date to be June 10$\pm$21 UT, 2004 (JD 2453167$\pm$21) for SN 2004dj. We also estimate the ejected nickel mass during the explosion to be $M{(}^{56}\mathrm{Ni})$ = 0.023 $\pm$ 0.005 $M_{\odot }$ from two different methods, which is typical for a SN II-P. We derive the explosion energy $E\approx 0.75_{-0.38}^{+0.56}\times 10^{51}$ erg, the ejecta mass $M\approx 10.0_{-5.2}^{+7.4}$ $M_{\odot }$, and the initial radius $R\approx 282_{-122}^{+253}$ $R_{\odot }$ for the presupernova star of SN 2004dj, which are consistent with other typical SNe II-P.

15 pages, 9 figures, accepted for publication in AJ